IEC 60238:2016

Edison screw lampholders

IEC 60238:2016 applies to lampholders with Edison thread E14, E27 and E40, designed for connection to the supply of lamps and semi-luminaires only. It also applies to switched-lampholders for use in AC circuits only, where the working voltage does not exceed 250 V r.m.s. This ninth edition cancels and replaces the eighth edition published in 2004, Amendment 1: 2008 and Amendment 2:2011. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) Addition of a pull test for certain E5 and E10 lampholders.
b) Annex D listing amended requirements/clauses which require products to be retested.

Douilles à vis Edison pour lampes

L'IEC 60238:2016 s'applique aux douilles à vis Edison E14, E27 et E40 destinées uniquement au raccordement des lampes et des semi-luminaires à l'alimentation. Elle s'applique aussi aux douilles à interrupteur destinées exclusivement aux circuits de courant alternatif dont la tension de travail ne dépasse pas 250 V (valeur efficace). Cette neuvième édition annule et remplace la huitième édition parue en 2004, l'Amendement 1: 2008 et l'Amendement 2:2011. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) Addition d'un essai de traction pour certaines douilles E5 et E10.
b) Une Annexe D répertoriant les exigences/articles amendés nécessitant la réalisation de nouveaux essais sur les produits.

General Information

• Status: Published
• Publication Date: 19-Jan-2020
• ICS: 29.140.10 - Lamp caps and holders
• Technical Committee: SC 34B - Lamp caps and holders
• Current Stage: PPUB - Publication issued
• Start Date: 14-Jul-2016
• Completion Date: 15-Jul-2016

Relations

• Amended By: IEC 60238:2016/AMD2:2020 - Amendment 2 - Edison screw lampholders
• Effective Date: 05-Sep-2023
• Amended By: IEC 60238:2016/AMD1:2017 - Amendment 1 - Edison screw lampholders
• Effective Date: 05-Sep-2023
• Revises: IEC 60238:2004/AMD2:2011 - Amendment 2 - Edison screw lampholders
• Effective Date: 05-Sep-2023
• Revises: IEC 60238:2004/AMD1:2008 - Amendment 1 - Edison screw lampholders
• Effective Date: 05-Sep-2023
• Revises: IEC 60238:2004 - Edison screw lampholders
• Effective Date: 05-Sep-2023

Overview

IEC 60238:2016 - Edition 9.0 is the International Electrotechnical Commission standard for Edison screw lampholders. It applies to lampholders with Edison threads E14, E27 and E40, and to certain E5 and E10 lampholders used with series-connected lamps. The standard covers lampholders intended for connection to lamps and semi-luminaires, including switched-lampholders for AC circuits with a working voltage up to 250 V r.m.s. This edition (2016) is a technical revision of the previous edition and introduces notable changes such as a pull test for some E5/E10 lampholders and an Annex D identifying clauses that require retesting.

Key topics and requirements

The standard specifies design, safety and test requirements including:

• Scope & classifications - applicability to indoor/outdoor, built-in and luminaire-integral lampholders, adapters and candle lampholders where relevant.
• Electrical safety - protection against electric shock, insulation resistance and electric strength tests, and switching requirements for switched-lampholders.
• Mechanical requirements - mechanical strength, pull and torque tests, impact and tumbling tests, and dimensional requirements for thread and contacts.
• Thermal and fire resistance - general heat resistance, resistance to heat, fire and tracking, and requirements to resist season cracking and corrosion.
• Terminals & earthing - terminal dimensions, connection requirements and provision for earthing where applicable.
• Creepage & clearance - minimum distances for impulse and operating voltages.
• Marking & documentation - labelling, standard ratings and product identification.
• Test methods & figures - extensive test apparatus, test caps and tables are included (mechanical, electrical and thermal test procedures, and normative/ informative annexes).
• Annexes - guidance for switches (Annex B referencing IEC 61058-1), special appliance requirements, season cracking test, and an Annex D listing amended clauses requiring retest.

Practical applications - who uses this standard

IEC 60238 is used by:

• Lampholder and lighting manufacturers for product design, compliance and type testing.
• Luminaire and appliance OEMs when integrating lampholders - lampholder clauses are applied alongside relevant appliance standards.
• Test laboratories and certification bodies for conformity assessment and safety testing.
• Specifiers and procurement teams looking to verify safety, interchangeability and mechanical robustness.
• Retailers and OEMs for guidance on which lampholders are intended for retail sale (some E10/E5 types and snap-on shells are restricted for manufacturer use).

Related standards

• IEC 61058-1 (switches) - guidance for switches used in lampholders (see Annex B).
• IEC 60529 - referenced for standard test finger (accessibility) used in mechanical tests.

Keywords: IEC 60238, Edison screw lampholders, E14 E27 E40, lampholder standards, switched lampholders, product testing, safety requirements, lighting components.

Standards Content (Sample)

IEC 60238 ®
Edition 9.0 2016-07
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Edison screw lampholders
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IEC 60238 ®
Edition 9.0 2016-07
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Edison screw lampholders
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.140.10 ISBN 978-2-8322-3538-6

– 2 – IEC 60238:2016 RLV © IEC 2016
CONTENTS
FOREWORD .4
1 General .
1 Scope .6
2 Normative references .7
3 Terms and definitions .8
4 General requirement . 12
5 General conditions for tests . 12
6 Standard ratings . 14
7 Classification . 15
8 Marking . 16
9 Dimensions . 18
14 Switched lampholders . 33
12 Provision for earthing . 27
13 Construction . 28
10 Protection against electric shock. 21
11 Terminals . 23
15 Moisture resistance, insulation resistance and electric strength . 34
16 Mechanical strength . 36
17 Screws, current-carrying parts and connections . 41
18 Creepage distances and clearances . 42
19 Normal operation . 46
20 General resistance to heat . 47
21 Resistance to heat, fire and tracking . 49
22 Resistance to excessive residual stresses (season cracking) and to rusting . 52
Annex A (normative) Season cracking/corrosion test . 73
Annex B (informative) Guidance for requirements in IEC 61058-1 applicable to
switches in lampholders (see 14.2) . 75
Annex C (informative) Guidance for special requirements in appliance standards –
Household and similar electrical appliances . 77
Annex D (informative) Schedule of amended subclauses containing more
serious/critical requirements which require products to be retested . 79
Bibliography . 80

Figure 1a –Nipple thread for lampholders: metric thread. Basic profile and design
profile for the nut and for the screw . 53
Figure 1b –Nipple thread for lampholders: ISO standard pipe thread. Basic profile and
design profile for the nut and for the screw . 54
Figure 2a – Gauges for metric ISO thread for nipples . 55
Figure 2b – Gauges for ISO standard pipe thread for nipples . 56
Figure 3 – Gauge for holes for backplate lampholder screws . 57
Figure 4 – Normal operation test apparatus . 58
Figure 5 – Test caps for the test of Clause 18 . 59

Figure 6 – Torque apparatus . 60
Figure 7 – Tumbling barrel . 61
Figure 8 – Impact-test apparatus . 62
Figure 9 – Pressure apparatus . 63
Figure 10 – Ball-pressure test apparatus . 63
Figure 11 – Test cap for the tests of 15.4 and 20.3 . 64
Figure 12 – Bending apparatus . 65
Figure 13 – Test cap A and test cap B for lampholders E14 (2 of 2) . 67
Figure 14 – Test cap for lampholders E27 . 68
Figure 15 – Test cap for lampholders E40 . 69
Figure 16 – Standard test finger (according to IEC 60529) . 70
Figure 17 – Clarification of some definitions . 71
Figure 18 – Preparation of specimens for the needle-flame test of 21.4 . 72

Table 1 – Thickness of screw shells and contacts . 19
Table 2 – Minimum effective screw lengths . 20
Table 3 – Dimensions of threaded entries and set screws . 21
Table 4 – Minimum dimensions of pillar-type terminals . 25
Table 5 – Minimum dimensions of screw-type terminals . 25
Table 6 – Pull and torque values . 31
Table 7 – Insertion torque . 33
Table 8 – Minimum and maximum removal torques . 33
Table 9 – Test cap dimensions . 37
Table 10 – Heights of fall . 38
Table 11 – Maximum deformation values . 40
Table 12 – Torque values . 41
Table 13a – Minimum distances for AC (50/60 Hz) sinusoidal voltages: Impulse
withstand category II . 44
Table 13b – Minimum distances for AC (50/60 Hz) sinusoidal voltages: Impulse
withstand category III . 45
Table 14 – Minimum distances for non-sinusoidal pulse voltages. 45
Table 15 – Heating cabinet temperatures . 48
Table A.1 – pH adjustment . 73

– 4 – IEC 60238:2016 RLV © IEC 2016
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EDISON SCREW LAMPHOLDERS
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
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International Standard IEC 60238 has been prepared by subcommittee 34B: Lamp caps and
holders, of IEC technical committee 34: Lamps and related equipment.
This ninth edition cancels and replaces the eighth edition published in 2004, Amendment 1:
2008 and Amendment 2:2011. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Addition of a pull test for certain E5 and E10 lampholders.
b) Annex D listing amended requirements/clauses which require products to be retested.
The text of this standard is based on the following documents:
FDIS Report on voting
34B/1852/FDIS 34B/1860/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
In this standard, the following print types are used:
– compliance statements: in italic type.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The “colour inside” logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this publication using a
colour printer.
– 6 – IEC 60238:2016 RLV © IEC 2016
EDISON SCREW LAMPHOLDERS
1 General
1 Scope
This International Standard applies to lampholders with Edison thread E14, E27 and E40,
designed for connection to the supply of lamps and semi-luminaires only.
It also applies to switched-lampholders for use in AC circuits only, where the working voltage
does not exceed 250 V r.m.s.
This standard also applies to lampholders with Edison thread E5 designed for connection to
the supply mains of series connected lamps, with a working voltage not exceeding 25 V, to be
used indoors, and to lampholders with Edison thread E10 designed for connection to the
supply mains of series connected lamps, with a working voltage not exceeding 60 V, to be
used indoors or outdoors. It also applies to lampholders E10 for building-in, for the
connection of single lamps to the supply. These lampholders are not intended for retail sale.
As far as it reasonably applies, this standard also covers lampholders other than lampholders
with Edison thread designed for connection of series-connected lamps to the supply.
NOTE This type of lampholder is for example used in Christmas tree lighting chains.
As far as it reasonably applies, this standard also covers adapters.
This standard also covers lampholders which are, wholly or partly, integral with a luminaire or
intended to be built into appliances. It covers the requirements for the lampholder only. For
all other requirements, such as protection against electric shock in the area of the terminals
or of the lamp cap, the requirements of the relevant appliance standard shall be are observed
and tested after building into the appropriate equipment, when that equipment is tested
according to its own standard. Such lampholders as well as lampholders provided with a
snap-on outer shell, for use by luminaire manufacturers only, are not for retail sale.
This standard applies to lampholders to be used indoors or outdoors in residential as well as
in industrial lighting installations. It also applies to candle lampholders. In locations where
special conditions prevail, as for street lighting, on board ships, in vehicles and in hazardous
locations, for example where explosions are liable to occur, special constructions may be
required.
NOTE 1 This standard does not apply to three-light lampholders E26d.
NOTE 2 This standard is based on the following data relative to lamps for general lighting
service:
– caps E14 are used for lamps with a current not exceeding 2 A;
– caps E27 are used for lamps with a current not exceeding 4 A;
– caps E40 are used for lamps with a current not exceeding 16 A, or 32 A if the nominal
voltage of the supply does not exceed 130 V (see 5.5 and 6.3).
___________
Requirements for lampholders suitable for semi-luminaires are under consideration.

NOTE 3 If the nominal voltage of the supply does not exceed 130 V, the maximum current for caps E40 is 32 A
(see 4.5 and 5.3).
NOTE 4 Where lampholders are used in luminaires, their maximum operating temperatures are
specified in IEC 60598.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document
and are indispensable for its application. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
NOTE With regard to IEC 60598-1, the references cited in this document are liable to change.
IEC 60061 (all parts), Lamp caps and holders together with gauges for the control of
interchangeability and safety
IEC 60061-1, Lamp caps and holders together with gauges for the control of
interchangeability and safety – Part 1: Lamp caps
IEC 60061-2, Lamp caps and holders together with gauges for the control of
interchangeability and safety – Part 2: Lampholders
IEC 60061-3, Lamp caps and holders together with gauges for the control of
interchangeability and safety – Part 3: Gauges
IEC 60068-2-20:1979, environmental testing – Part 2: Tests – Test T: Soldering
IEC 60068-2-32:1975, Basic environmental testing procedures – Part 2-32: Tests – Test Ed:
Free fall
IEC 60068-2-75:1997 2014, Environmental testing – Part 2-75: Tests – Test Eh: Hammer
tests
IEC 60112:1979 2003, Method for the determination of the proof and the comparative
tracking indices of solid insulating materials under moist conditions
Amendment 1:2009
IEC 60227 (all parts), Polyvinyl chloride insulated cables of rated voltages up to and
including 450/750 V
IEC 60245 (all parts), Rubber insulated cables – Rated voltages up to and including
450/750 V
IEC 60335-1:2001, Household and similar electrical appliances – Safety – Part 1: General
requirements
IEC 60352-1:1997, Solderless connections – Part 1: Wrapped connections – General
requirements, test methods and practical guidance
IEC 60399, Barrel thread for lampholders with shade holder ring

– 8 – IEC 60238:2016 RLV © IEC 2016
**)
IEC 60417-DB:2002 , Graphical symbols for use on equipment (available at:
http://www.graphical-symbols.info/equipment)
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
Amendment 1:1999
Amendment 2:2013
IEC 60598 (all parts and sections), Luminaires
IEC 60598-1, Luminaires – Part 1: General requirements and tests
IEC 60664-1:1992, Insulation coordination for equipment within low-voltage systems – Part 1:
***)
Principles, requirements and tests
Amendment 1 (2000)
Amendment 2 (2002)
IEC 60695-2-2:1991, Fire hazard testing – Part 2: Test methods – Section 2: Needle-flame
test
IEC 60695-2-10:2000, Fire hazard testing – Part 2–10: Glowing/hot-wire based test methods
– Glow-wire apparatus and common test procedure
IEC 60630, Maximum lamp outlines for incandescent lamps
IEC 60695-2-11:2000 2014, Fire hazard testing – Part 2-11: Glowing/hot-wire based test
methods – Glow-wire flammability test method for end-products (GWEPT)
IEC 60695-11-5, Fire hazard testing – Part 11-5: Test flames – Needle-flame test method –
Apparatus, confirmatory test arrangement and guidance
IEC 61058-1:2000, Switches for appliances – Part 1: General requirements
ISO 4046-4:2002, Paper, board, pulps and related terms – Vocabulary – Part 4: Paper and
board grades and converted products
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
cord-grip lampholder
lampholder incorporating a method of retaining a flexible cord by which it may then be
suspended
___________
**) “DB” refers to the IEC on-line database.
***) A consolidated edition 1.2 (2002) exists including edition 1.0 (1992) and its amendment 1 (2000) and
amendment 2 (2002).
A consolidated edition 2.2 (2013) exists including edition 2.0 (1989) and its Amendment 1 (1999) and
Amendment 2 (2013).
3.2
threaded entry lampholder
lampholder incorporating a threaded component at the point of entry of the supply wires
permitting the lampholder to be mounted on a mating threaded support
Note 1 to entry: A threaded entry lampholder was formerly called a “nipple lampholder”.
3.3
backplate lampholder
lampholder so designed as to be suitable for mounting by means of an associated or integral
backplate, directly onto a supporting surface or appropriate box
3.4
lampholder for building-in
lampholder designed to be built into a luminaire, an additional enclosure or the like
3.4.1
unenclosed lampholder
lampholder for building-in so designed that it requires additional means, for example an
enclosure, to meet the requirements of this standard with regard to protection against electric
shock
3.4.2
enclosed lampholder
lampholder for building-in so designed that on its own it fulfils the requirements of this
standard with regard to protection against electric shock and IP classification, if appropriate
3.5
independent lampholder
lampholder so designed that it can be mounted separately from a luminaire and at the same
time providing all the necessary protection according to its classification and marking
3.6
terminal/contact assembly
part or assembly of parts which provides a means of connection between the termination of a
supply conductor and the contact making surfaces of the corresponding lamp cap
Note 1 to entry: For clarification of some definitions, see also Figure 17.
3.7
outer shell
cylindrical component protecting the user from contact with the lamp cap.
Note 1 to entry: It may or may not be provided with an external screw thread for fixing a shade ring.
Note 2 to entry: For clarification of some definitions, see also Figure 17.
3.7.1
snap-on outer shell
outer shell for screwless assembly which does not contain the screw shell
Note 1 to entry: The lampholder should not be used when the snap-on outer shell is removed. It is therefore
recommended to place an approval mark, if provided, in such a way that it is not visible when this type of outer
shell is removed.
3.8
screw shell
cylindrical component having an internal screw thread of Edison form for the retention of the
corresponding lamp (cap)
– 10 – IEC 60238:2016 RLV © IEC 2016
Note 1 to entry: In some constructions, the screw shell is permanently fixed to or integral with the outer shell.
Note 2 to entry: For clarification of some definitions, see also Figure 17.
3.9
insulating ring
cylindrical intermediate piece of insulating material separating a metal screw shell and a
metal outer shell
Note 1 to entry: For clarification of some definitions, see also Figure 17.
3.10
shade ring
cylindrical component having an internal thread or other means to engage a corresponding
support on the outer shell and intended to carry or retain a shade
Note 1 to entry: For clarification of some definitions, see also Figure 17.
3.11
dome
part of a cord-grip lampholder or threaded entry lampholder which shields the connecting
terminals
Note 1 to entry: For clarification of some definitions, see also Figure 17.
3.12
basic insulation
insulation applied to live parts to provide basic protection against electric shock
Note 1 to entry: Basic insulation does not necessarily include insulation used exclusively for functional purposes.
3.13
supplementary insulation
independent insulation applied in addition to basic insulation in order to provide protection
against electric shock in the event of a failure of basic insulation
3.14
double insulation
insulation comprising both basic insulation and supplementary insulation
3.15
reinforced insulation
single insulation system applied to live parts, which provides a degree of protection against
electric shock equivalent to double insulation under the conditions specified
Note 1 to entry: The term "insulation system" does not imply that the insulation must be is one homogeneous
piece. It may comprise several layers which cannot be tested singly as supplementary or basic insulation.
3.16
live part
conductive part which may cause an electric shock
3.17
type test
test or series of tests made on a type test sample, for the purpose of checking compliance of
the design of a given product with the requirements of the relevant standard

3.18
type test sample
sample consisting of one or more similar specimens submitted by the manufacturer or
responsible vendor for the purpose of a type test
3.19
semi-luminaire
unit similar to a self-ballasted lamp but designed to utilize a replaceable light source and/or
starting device
3.20
rated operating temperature
highest temperature for which the holder is designed
3.21
rated minimum temperature
lowest temperature for which the holder is designed (applicable only to lampholders intended
for use in refrigerators and food freezers)
3.22
angled lampholder
lampholder, the rear side of which (threaded entry and/or dome) is at an angled position to
the screw shell axis
3.23
lampholder with retention device
lampholder with a device intended to prevent the lamp from becoming loose in the holder
Note 1 to entry: Lamps may can, for example, become loose due to changes in temperature or to vibrations.
3.24
impulse withstand category
numeral defining a transient overvoltage condition
Note 1 to entry: Impulse withstand categories I, II, III and IV are used.
a) Purpose of classification of impulse withstand categories
Impulse withstand categories are to distinguish different degrees of availability of equipment with regard to
required expectations on continuity of service and on an acceptable risk of failure.
By selection of impulse withstand levels of equipment insulation, co-ordination can be achieved in the whole
installation, reducing the risk of failure to an acceptable level providing a basis for overvoltage control.
A higher characteristic numeral of an impulse withstand category indicates a higher specific impulse withstand
of the equipment and offers a wider choice of methods for overvoltage control.
The concept of impulse withstand category is used for equipment energized directly from the mains.
b) Description of impulse withstand categories
Equipment of impulse withstand category I is equipment which is intended to be connected to the fixed
electrical installations of buildings. Protective means are taken outside the equipment – either in the fixed
installation or between the fixed installation and the equipment – to limit transient overvoltages to the specific
level.
Equipment of impulse withstand category II is equipment to be connected to the fixed electrical installations of
buildings.
Equipment of impulse withstand category III is equipment which is part of the fixed electrical installations and
other equipment where a higher degree of availability is expected.
Equipment of impulse withstand category IV is for use at or in the proximity of the origin of the electrical
installations of buildings upstream of the main distribution board.
3.25
primary circuit
circuit which is directly connected to the AC mains supply

– 12 – IEC 60238:2016 RLV © IEC 2016
Note 1 to entry: It includes, for example, the means for connection to the AC mains supply, the primary windings
of transformers, motors and other loading devices.
3.26
secondary circuit
circuit which has no direct connection to a primary circuit and derives its power from a
transformer, converter or equivalent isolation device, or from a battery
Note 1 to entry: Exception: autotransformers. Although having direct connection to a primary circuit, the tapped
part of them is also deemed to be a secondary circuit in the sense of this definition.
Note 2 to entry: Mains transients in such a circuit are attenuated by the corresponding primary windings. Also
inductive ballasts reduce the mains transient voltage height. Therefore, components located after a primary circuit
or after an inductive ballast can be suited for an impulse withstand category of one step lower, i.e. for impulse
withstand category II.
3.27
adapter
component used for the electrical and mechanical connection of a lamp to a lampholder
Note 1 to entry: This definition is specific for this standard. The definition of an adapter in principle could vary
very much depending on its use. In most cases such a component is used to bridge differences in the screw thread
diameter between the lampholder and the lamp.
3.28
enclosed reinforced insulated lampholder
lampholder for building-in so designed that on its own it fulfils the requirements for double or
reinforced insulated parts in class II applications
3.29
partly reinforced insulated lampholder
lampholder for building-in so designed that some parts of the lampholder require additional
means to fulfil the requirements with regard to double or reinforced insulation
Note 1 to entry: In some cases, the dimensions might be achieved only after mounting into the luminaire.
4 General requirement
Lampholders shall be so designed and constructed that in normal use they function reliably
and cause no danger to persons or surroundings.
In general, compliance is checked by carrying out all the tests specified.
In addition, the enclosure of independent lampholders shall comply with the requirements of
IEC 60598-1, including the classification and marking requirements of that standard.
5 General conditions for tests
5.1 Tests according to this standard are type tests.
NOTE The requirements and tolerances permitted by this standard are related to testing of a type test sample
submitted for that purpose.
Compliance of the type test sample does not ensure compliance of the whole production of a manufacturer with
this safety standard.
In addition to type testing, conformity of production is the responsibility of the manufacturer and may can include
routine tests and quality assurance.

For further information (inclusion of guidance on conformity testing during manufacture is in preparation) see
*****)
IEC 60061-4 .
5.2 Unless otherwise specified, the tests are made at an ambient temperature of 20 °C ±
5 °C and with the holder tested as delivered and installed as in normal use.
5.3 The tests and inspections are carried out on a total of
– nine specimens for non-switched lampholders, or
– 12 specimens for switched lampholders
in the following order of clauses:
– three specimens: Clauses 2 to 13 (except for 10.1 and 11.2) and Clauses 15 to 18;
– three specimens: Clause 14 (switched-lampholder tests only);
– three specimens: 10.1 and Clauses 19 and 20;
– two specimens: Clause 21 (of which one specimen for the test of 21.1 and the other for
the tests of 21.3 or 21.4);
– one specimen: 21.5 and Clause 22.
For testing lampholders with a retention device, the retention device shall be removed.
For testing lampholders with a retention device according to 13.14, three additional
specimens are required with the retention device kept in place.
NOTE For testing of screwless terminals according to 11.2, separate specimens are required
in addition.
5.4 In case of doubt, gauges, test caps and mandrels are introduced into the specimens,
unless otherwise specified, by applying the following torques:
– 0,2 Nm for lampholders E5;
– 0,2 Nm for lampholders E10;
– 0,2 Nm for lampholders E14;
– 0,4 Nm for lampholders E27;
– 0,8 Nm for lampholders E40.
5.5 For lampholders E40 with a rated current of 32 A, the tests shall be based on this rated
current.
5.6 Lampholders are deemed to comply with this standard if no specimen fails in the
complete series of tests specified in 5.3.
If one specimen fails in one test, that test and the preceding ones which may have influenced
the result of that test are repeated on another set of specimens to the number required by
5.3, all of which shall then comply with the repeated tests and with the subsequent tests.
Lampholders are deemed not to comply with this standard if there are more failures than one.
NOTE In general, it will only be necessary to repeat the relevant test unless the specimen fails in the tests
according to clauses 18 and 19, or if failure occurs with regard to resilient side or central contact(s); in these
cases, both tests are repeated with a second set of three specimens.
___________
)
****
IEC 60061-4: Lamp caps and holders together with gauges for the control of interchangeability and safety –
Part 4: Guidelines and general information

– 14 – IEC 60238:2016 RLV © IEC 2016
The applicant may submit, together with the first set of specimens, the additional set which may be wanted in case
of failure of one specimen. The testing station shall then, without further request, test the additional specimens
and will reject only if a further failure occurs.
If the additional set of specimens is not submitted at the same time, a failure of one specimen entails a rejection.
6 Standard ratings
6.1 Standard rated voltages are 250 V and 500 V and 750 V.
For lampholders E14, and for switched lampholders E27, a rated voltage of 250 V only is
allowed.
For lampholders E5 and E10 intended for the connection of series-connected lamps to the
supply, the rated voltage shall not exceed 25 V for lampholders E5 and not exceed 60 V for
lampholders E10.
NOTE 1 These values refer to the voltage between parts of different polarity.
For lampholders E10 intended for the connection of single lamps to the supply, a rated
voltage of 250 V only is allowed.
NOTE 2 These lampholders should be are also used for such special cases as series-connected lamps, whereby,
because of the low number of lamps, 60 V per lampholder is exceeded.
With the exception given for lampholders E5 and E10, the rated voltage shall be not less than
250 V. Additionally a rated voltage of 125 V is allowed for lampholders E40.
Compliance is checked by inspection of the marking.
6.2 Standard rated currents are
– 0,2 A for lampholders E5;
– 0,5 A for lampholders E10;
– 2 A for lampholders E14;
– 2 A for switched-lampholders E27;
– 4 A for other lampholders E27;
– 16 A for lampholders E40.
The rated current shall be not less than the standard value.
Compliance is checked by inspection of the marking.
6.3 Lampholders E40 to be used on 125 V (see note) installations may have an additional
nominal rating of 32 A.
NOTE This nominal rating covers the voltages up to and including 130 V.
Compliance is checked by inspection of the marking.
6.4 The rated operating temperature for lampholders intended for use in high temperature
conditions (T marked holders) shall be not lower than 140 °C for lampholders E14, not lower
than 170 °C for lampholders E27 and not lower than 230 °C for lampholders E40.
NOTE The values of the temperature marking should be increased by steps of 10 °C.
Compliance is checked by inspection of the marking.

NOTE The rated operating temperatures for Edison screw lampholders without T marking are given in IEC 60598-1,
Table 12.1. They are
– 135 °C for lampholders E14;
– 165 °C for lampholders E27;
– 225 °C for lampholders E40.
7 Classification
Lampholders are classified as defined in 7.1 to 7.6.
7.1 According to the material of the external parts:
– lampholders of insulating material;
– metal lampholders.
NOTE Lampholders with external parts consisting partly of metal and lampholders comprising external parts of
insulating material with a conductive outer surface, for example a metallized outer shell, are considered as metal
lampholders (see 13.3). This does not apply to threaded entries and external parts, for example a metal shade ring
mounted onto the outside of a lampholder of insulating material, which cannot become live even in the case of an
insulation fault. Metal holders with insulating coverings are considered as metal lampholders (see 10.5).
In order to check whether or not a surface is conductive, two stripe-electrodes 1,5 mm wide,
25 mm long and with a distance of 2 mm from each other are applied to the surface (e.g. with
silver conductive paint). In accordance with 15.4, the insulating resistance is measured
between the stripes. The surface is considered to be conductive if the resistance is less than
5 MΩ.
7.2 According to degree of protection against ingress of water:
– ordinary lampholders;
– drip-proof lampholders.
7.3 According to method of fixing:
– threaded entry lampholders;
– cord-grip lampholders;
– backplate lampholders;
– other lampholders.
NOTE Examples of other lampholders are lampholders provided with a mechanical suspension device, e.g. a
hook.
7.4 According to type:
– switched-lampholders, provided with an integral switch to control the supply to the lamp;
– non-switched lampholders.
7.5 According to protection against electric shock:
– unenclosed lampholders;
– enclosed lampholders;
– independent lampholders;
– partly reinforced insulated lampholders;
– enclosed reinforced insulated lampholders.
NOTE Where a lampholder is used with a working voltage of 50 % or less of its maximum rating, it can be
regarded as equivalent to a reinforced insulated lampholder.

– 16 – IEC 60238:2016 RLV © IEC 2016
7.6 According to resistance to heat:
– lampholders for rated operating temperatures up to the limits given in 6.4;
– lampholders for operating in high temperature conditions (T marked holders).
8 Marking
8.1 Lampholders, other than lampholders E5 and E10, shall be marked with the following:
– rated current, in amperes;
– rated voltage, in volts, and rated pulse voltage, in kV, if higher than
• 2,5 kV for lampholders rated 250 V,
• 4 kV for lampholders rated 500 V;
NOTE The rated pulse voltage of the lampholder (in kV) should either be marked on the
lampholder or made available in the manufacturer’s catalogue or the like.
NOTE 1 Some lampholders still show rated voltages higher than 500 V. This is an earlier way of expressing
the permissible pulse voltage via a rated voltage. For such lampholders, the creepage distances and
clearances can be found in IEC 60598-1.
– symbol for nature of current, if required (for switched lampholders only);
– mark of origin (this may take the form of a trade mark, manufacturer's identification mark
or the name of the responsible vendor);
– type reference;
Available technical documentation of the manufacturer like printed catalogues or online
catalogues should allow a clear identification of a lampholder either by a unique catalogue
number or by an identifying reference on the holder, specifying the essential
characteristic features and the basic design of the product supplemented by a clear
description. Variations of the basic design like for example different cable length, fixing
means, colours etc., which do not affect safety or performance of the lampholder, can be
disregarded in the type reference marked on the product. Variations included in the type
testing procedure are listed in the corresponding test reports.
– the degree of protection against ingress of water for drip-proof lampholders (see 8.2);
– rated operating temperature "T", indicating the highest operating temperature, if
applicable.
The marking of the rated operating temperature is not required for lampholders whose
exterior is made wholly of ceramic material. For these lampholders, this information, if
applicable, shall either be marked on the lampholder or be made available in the ma
...

IEC 60238 ®
Edition 9.0 2016-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Edison screw lampholders
Douilles à vis edison pour lampes

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IEC 60238 ®
Edition 9.0 2016-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Edison screw lampholders
Douilles à vis edison pour lampes

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.140.10 ISBN 978-2-8322-3465-5

– 2 – IEC 60238:2016 © IEC 2016
CONTENTS
FOREWORD .4
1 Scope .6
2 Normative references .7
3 Terms and definitions .8
4 General requirement . 11
5 General conditions for tests . 11
6 Standard ratings . 12
7 Classification . 13
8 Marking . 14
9 Dimensions . 17
10 Protection against electric shock. 19
11 Terminals . 22
12 Provision for earthing . 25
13 Construction . 26
14 Switched lampholders . 31
15 Moisture resistance, insulation resistance and electric strength . 32
16 Mechanical strength . 35
17 Screws, current-carrying parts and connections . 39
18 Creepage distances and clearances . 41
19 Normal operation . 44
20 General resistance to heat . 45
21 Resistance to heat, fire and tracking . 47
22 Resistance to excessive residual stresses (season cracking) and to rusting . 50
Annex A (normative) Season cracking/corrosion test . 71
Annex B (informative) Guidance for requirements in IEC 61058-1 applicable to
switches in lampholders (see 14.2) . 73
Annex C (informative) Guidance for special requirements in appliance standards –
Household and similar electrical appliances . 75
Annex D (informative) Schedule of amended subclauses containing more
serious/critical requirements which require products to be retested . 77
Bibliography . 78

Figure 1a –Nipple thread for lampholders: metric thread. Basic profile and design
profile for the nut and for the screw . 51
Figure 1b –Nipple thread for lampholders: ISO standard pipe thread. Basic profile and
design profile for the nut and for the screw . 52
Figure 2a – Gauges for metric thread for nipples . 53
Figure 2b – Gauges for ISO standard pipe thread for nipples . 54
Figure 3 – Gauge for holes for backplate lampholder screws . 55
Figure 4 – Normal operation test apparatus . 56
Figure 5 – Test caps for the test of Clause 18 . 57
Figure 6 – Torque apparatus . 58
Figure 7 – Tumbling barrel . 59

Figure 8 – Impact-test apparatus . 60
Figure 9 – Pressure apparatus . 61
Figure 10 – Ball-pressure test apparatus . 61
Figure 11 – Test cap for the tests of 15.4 and 20.3 . 62
Figure 12 – Bending apparatus . 63
Figure 13 – Test cap A and test cap B for lampholders E14 . 65
Figure 14 – Test cap for lampholders E27 . 66
Figure 15 – Test cap for lampholders E40 . 67
Figure 16 – Standard test finger (according to IEC 60529) . 68
Figure 17 – Clarification of some definitions . 69
Figure 18 – Preparation of specimens for the needle-flame test of 21.4 . 70

Table 1 – Thickness of screw shells and contacts . 18
Table 2 – Minimum effective screw lengths . 18
Table 3 – Dimensions of threaded entries and set screws . 19
Table 4 – Minimum dimensions of pillar-type terminals . 23
Table 5 – Minimum dimensions of screw-type terminals . 24
Table 6 – Pull and torque values . 29
Table 7 – Insertion torque . 31
Table 8 – Minimum and maximum removal torques . 31
Table 9 – Test cap dimensions . 35
Table 10 – Heights of fall . 37
Table 11 – Maximum deformation values . 38
Table 12 – Torque values . 40
Table 13a – Minimum distances for AC (50/60 Hz) sinusoidal voltages: Impulse
withstand category II . 42
Table 13b – Minimum distances for AC (50/60 Hz) sinusoidal voltages: Impulse
withstand category III . 43
Table 14 – Minimum distances for non-sinusoidal pulse voltages. 43
Table 15 – Heating cabinet temperatures . 46
Table A.1 – pH adjustment . 71

– 4 – IEC 60238:2016 © IEC 2016
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EDISON SCREW LAMPHOLDERS
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60238 has been prepared by subcommittee 34B: Lamp caps and
holders, of IEC technical committee 34: Lamps and related equipment.
This ninth edition cancels and replaces the eighth edition published in 2004, Amendment 1:
2008 and Amendment 2:2011. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Addition of a pull test for certain E5 and E10 lampholders.
b) Annex D listing amended requirements/clauses which require products to be retested.

The text of this standard is based on the following documents:
FDIS Report on voting
34B/1852/FDIS 34B/1860/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
In this standard, the following print types are used:
– compliance statements: in italic type.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 6 – IEC 60238:2016 © IEC 2016
EDISON SCREW LAMPHOLDERS
1 Scope
This International Standard applies to lampholders with Edison thread E14, E27 and E40,
designed for connection to the supply of lamps and semi-luminaires only.
It also applies to switched-lampholders for use in AC circuits only, where the working voltage
does not exceed 250 V r.m.s.
This standard also applies to lampholders with Edison thread E5 designed for connection to
the supply mains of series connected lamps, with a working voltage not exceeding 25 V, to be
used indoors, and to lampholders with Edison thread E10 designed for connection to the
supply mains of series connected lamps, with a working voltage not exceeding 60 V, to be
used indoors or outdoors. It also applies to lampholders E10 for building-in, for the
connection of single lamps to the supply. These lampholders are not intended for retail sale.
As far as it reasonably applies, this standard also covers lampholders other than lampholders
with Edison thread designed for connection of series-connected lamps to the supply.
NOTE This type of lampholder is for example used in Christmas tree lighting chains.
As far as it reasonably applies, this standard also covers adapters.
This standard also covers lampholders which are, wholly or partly, integral with a luminaire or
intended to be built into appliances. It covers the requirements for the lampholder only. For
all other requirements, such as protection against electric shock in the area of the terminals
or of the lamp cap, the requirements of the relevant appliance standard are observed and
tested after building into the appropriate equipment, when that equipment is tested according
to its own standard. Such lampholders as well as lampholders provided with a snap-on outer
shell, for use by luminaire manufacturers only, are not for retail sale.
This standard applies to lampholders to be used indoors or outdoors in residential as well as
in industrial lighting installations. It also applies to candle lampholders. In locations where
special conditions prevail, as for street lighting, on board ships, in vehicles and in hazardous
locations, for example where explosions are liable to occur, special constructions may be
required.
This standard does not apply to three-light lampholders E26d.
This standard is based on the following data relative to lamps for general lighting service:
– caps E14 are used for lamps with a current not exceeding 2 A;
– caps E27 are used for lamps with a current not exceeding 4 A;
– caps E40 are used for lamps with a current not exceeding 16 A, or 32 A if the nominal
voltage of the supply does not exceed 130 V (see 5.5 and 6.3).
Where lampholders are used in luminaires, their maximum operating temperatures are
specified in IEC 60598.
___________
Requirements for lampholders suitable for semi-luminaires are under consideration.

2 Normative references
The following documents, in whole or in part, are normatively referenced in this document
and are indispensable for its application. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60061-1, Lamp caps and holders together with gauges for the control of
interchangeability and safety – Part 1: Lamp caps
IEC 60061-2, Lamp caps and holders together with gauges for the control of
interchangeability and safety – Part 2: Lampholders
IEC 60061-3, Lamp caps and holders together with gauges for the control of
interchangeability and safety – Part 3: Gauges
IEC 60068-2-32:1975, Basic environmental testing procedures – Part 2-32: Tests – Test Ed:
Free fall
IEC 60068-2-75:2014, Environmental testing – Part 2-75: Tests – Test Eh: Hammer tests
IEC 60112:2003, Method for the determination of the proof and the comparative tracking
indices of solid insulating materials
Amendment 1:2009
IEC 60227 (all parts), Polyvinyl chloride insulated cables of rated voltages up to and
including 450/750 V
IEC 60245 (all parts), Rubber insulated cables – Rated voltages up to and including
450/750 V
IEC 60352-1:1997, Solderless connections – Part 1: Wrapped connections – General
requirements, test methods and practical guidance
IEC 60399, Barrel thread for lampholders with shade holder ring
IEC 60417, Graphical symbols for use on equipment (available at: http://www.graphical-
symbols.info/equipment)
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
Amendment 1:1999
Amendment 2:2013
IEC 60598-1, Luminaires – Part 1: General requirements and tests
IEC 60630, Maximum lamp outlines for incandescent lamps
IEC 60695-2-11:2014, Fire hazard testing – Part 2-11: Glowing/hot-wire based test methods
– Glow-wire flammability test method for end-products (GWEPT)
IEC 60695-11-5, Fire hazard testing – Part 11-5: Test flames – Needle-flame test method –
Apparatus, confirmatory test arrangement and guidance
___________
A consolidated edition 2.2 (2013) exists including edition 2.0 (1989) and its Amendment 1 (1999) and
Amendment 2 (2013).
– 8 – IEC 60238:2016 © IEC 2016
IEC 61058-1:2000, Switches for appliances – Part 1: General requirements
ISO 4046-4:2002, Paper, board, pulps and related terms – Vocabulary – Part 4: Paper and
board grades and converted products
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
cord-grip lampholder
lampholder incorporating a method of retaining a flexible cord by which it may then be
suspended
3.2
threaded entry lampholder
lampholder incorporating a threaded component at the point of entry of the supply wires
permitting the lampholder to be mounted on a mating threaded support
Note 1 to entry: A threaded entry lampholder was formerly called a “nipple lampholder”.
3.3
backplate lampholder
lampholder so designed as to be suitable for mounting by means of an associated or integral
backplate, directly onto a supporting surface or appropriate box
3.4
lampholder for building-in
lampholder designed to be built into a luminaire, an additional enclosure or the like
3.4.1
unenclosed lampholder
lampholder for building-in so designed that it requires additional means, for example an
enclosure, to meet the requirements of this standard with regard to protection against electric
shock
3.4.2
enclosed lampholder
lampholder for building-in so designed that on its own it fulfils the requirements of this
standard with regard to protection against electric shock and IP classification, if appropriate
3.5
independent lampholder
lampholder so designed that it can be mounted separately from a luminaire and at the same
time providing all the necessary protection according to its classification and marking
3.6
terminal/contact assembly
part or assembly of parts which provides a means of connection between the termination of a
supply conductor and the contact making surfaces of the corresponding lamp cap
Note 1 to entry: For clarification of some definitions, see also Figure 17.
3.7
outer shell
cylindrical component protecting the user from contact with the lamp cap.
Note 1 to entry: It may or may not be provided with an external screw thread for fixing a shade ring.

Note 2 to entry: For clarification of some definitions, see also Figure 17.
3.7.1
snap-on outer shell
outer shell for screwless assembly which does not contain the screw shell
Note 1 to entry: The lampholder should not be used when the snap-on outer shell is removed. It is therefore
recommended to place an approval mark, if provided, in such a way that it is not visible when this type of outer
shell is removed.
3.8
screw shell
cylindrical component having an internal screw thread of Edison form for the retention of the
corresponding lamp (cap)
Note 1 to entry: In some constructions, the screw shell is permanently fixed to or integral with the outer shell.
Note 2 to entry: For clarification of some definitions, see also Figure 17.
3.9
insulating ring
cylindrical intermediate piece of insulating material separating a metal screw shell and a
metal outer shell
Note 1 to entry: For clarification of some definitions, see also Figure 17.
3.10
shade ring
cylindrical component having an internal thread or other means to engage a corresponding
support on the outer shell and intended to carry or retain a shade
Note 1 to entry: For clarification of some definitions, see also Figure 17.
3.11
dome
part of a cord-grip lampholder or threaded entry lampholder which shields the connecting
terminals
Note 1 to entry: For clarification of some definitions, see also Figure 17.
3.12
basic insulation
insulation applied to live parts to provide basic protection against electric shock
Note 1 to entry: Basic insulation does not necessarily include insulation used exclusively for functional purposes.
3.13
supplementary insulation
independent insulation applied in addition to basic insulation in order to provide protection
against electric shock in the event of a failure of basic insulation
3.14
double insulation
insulation comprising both basic insulation and supplementary insulation
3.15
reinforced insulation
single insulation system applied to live parts, which provides a degree of protection against
electric shock equivalent to double insulation under the conditions specified
Note 1 to entry: The term "insulation system" does not imply that the insulation is one homogeneous piece. It may
comprise several layers which cannot be tested singly as supplementary or basic insulation.

– 10 – IEC 60238:2016 © IEC 2016
3.16
live part
conductive part which may cause an electric shock
3.17
type test
test or series of tests made on a type test sample, for the purpose of checking compliance of
the design of a given product with the requirements of the relevant standard
3.18
type test sample
sample consisting of one or more similar specimens submitted by the manufacturer or
responsible vendor for the purpose of a type test
3.19
semi-luminaire
unit similar to a self-ballasted lamp but designed to utilize a replaceable light source and/or
starting device
3.20
rated operating temperature
highest temperature for which the holder is designed
3.21
rated minimum temperature
lowest temperature for which the holder is designed (applicable only to lampholders intended
for use in refrigerators and food freezers)
3.22
angled lampholder
lampholder, the rear side of which (threaded entry and/or dome) is at an angled position to
the screw shell axis
3.23
lampholder with retention device
lampholder with a device intended to prevent the lamp from becoming loose in the holder
Note 1 to entry: Lamps can, for example, become loose due to changes in temperature or to vibrations.
3.24
impulse withstand category
numeral defining a transient overvoltage condition
Note 1 to entry: Impulse withstand categories I, II, III and IV are used.
a) Purpose of classification of impulse withstand categories
Impulse withstand categories are to distinguish different degrees of availability of equipment with regard to
required expectations on continuity of service and on an acceptable risk of failure.
By selection of impulse withstand levels of equipment insulation, co-ordination can be achieved in the whole
installation, reducing the risk of failure to an acceptable level providing a basis for overvoltage control.
A higher characteristic numeral of an impulse withstand category indicates a higher specific impulse withstand
of the equipment and offers a wider choice of methods for overvoltage control.
The concept of impulse withstand category is used for equipment energized directly from the mains.
b) Description of impulse withstand categories
Equipment of impulse withstand category I is equipment which is intended to be connected to the fixed
electrical installations of buildings. Protective means are taken outside the equipment – either in the fixed
installation or between the fixed installation and the equipment – to limit transient overvoltages to the specific
level.
Equipment of impulse withstand category II is equipment to be connected to the fixed electrical installations of
buildings.
Equipment of impulse withstand category III is equipment which is part of the fixed electrical installations and
other equipment where a higher degree of availability is expected.
Equipment of impulse withstand category IV is for use at or in the proximity of the origin of the electrical
installations of buildings upstream of the main distribution board.
3.25
primary circuit
circuit which is directly connected to the AC mains supply
Note 1 to entry: It includes, for example, the means for connection to the AC mains supply, the primary windings
of transformers, motors and other loading devices.
3.26
secondary circuit
circuit which has no direct connection to a primary circuit and derives its power from a
transformer, converter or equivalent isolation device, or from a battery
Note 1 to entry: Exception: autotransformers. Although having direct connection to a primary circuit, the tapped
part of them is also deemed to be a secondary circuit in the sense of this definition.
Note 2 to entry: Mains transients in such a circuit are attenuated by the corresponding primary windings. Also
inductive ballasts reduce the mains transient voltage height. Therefore, components located after a primary circuit
or after an inductive ballast can be suited for an impulse withstand category of one step lower, i.e. for impulse
withstand category II.
3.27
adapter
component used for the electrical and mechanical connection of a lamp to a lampholder
Note 1 to entry: This definition is specific for this standard. The definition of an adapter in principle could vary
very much depending on its use. In most cases such a component is used to bridge differences in the screw thread
diameter between the lampholder and the lamp.
3.28
enclosed reinforced insulated lampholder
lampholder for building-in so designed that on its own it fulfils the requirements for double or
reinforced insulated parts in class II applications
3.29
partly reinforced insulated lampholder
lampholder for building-in so designed that some parts of the lampholder require additional
means to fulfil the requirements with regard to double or reinforced insulation
Note 1 to entry: In some cases, the dimensions might be achieved only after mounting into the luminaire.
4 General requirement
Lampholders shall be so designed and constructed that in normal use they function reliably
and cause no danger to persons or surroundings.
In general, compliance is checked by carrying out all the tests specified.
In addition, the enclosure of independent lampholders shall comply with the requirements of
IEC 60598-1, including the classification and marking requirements of that standard.
5 General conditions for tests
5.1 Tests according to this standard are type tests.
NOTE The requirements and tolerances permitted by this standard are related to testing of a type test sample
submitted for that purpose.
– 12 – IEC 60238:2016 © IEC 2016
Compliance of the type test sample does not ensure compliance of the whole production of a manufacturer with
this safety standard.
In addition to type testing, conformity of production is the responsibility of the manufacturer and can include
routine tests and quality assurance.
For further information on conformity testing during manufacture see IEC 60061-4.
5.2 Unless otherwise specified, the tests are made at an ambient temperature of 20 °C ±
5 °C and with the holder tested as delivered and installed as in normal use.
5.3 The tests and inspections are carried out on a total of
– nine specimens for non-switched lampholders, or
– 12 specimens for switched lampholders
in the following order of clauses:
– three specimens: Clauses 2 to 13 (except for 10.1 and 11.2) and Clauses 15 to 18;
– three specimens: Clause 14 (switched-lampholder tests only);
– three specimens: 10.1 and Clauses 19 and 20;
– two specimens: Clause 21 (of which one specimen for the test of 21.1 and the other for
the tests of 21.3 or 21.4);
– one specimen: 21.5 and Clause 22.
For testing lampholders with a retention device, the retention device shall be removed.
For testing lampholders with a retention device according to 13.14, three additional
specimens are required with the retention device kept in place.
For testing of screwless terminals according to 11.2, separate specimens are required in
addition.
5.4 In case of doubt, gauges, test caps and mandrels are introduced into the specimens,
unless otherwise specified, by applying the following torques:
– 0,2 Nm for lampholders E5;
– 0,2 Nm for lampholders E10;
– 0,2 Nm for lampholders E14;
– 0,4 Nm for lampholders E27;
– 0,8 Nm for lampholders E40.
5.5 For lampholders E40 with a rated current of 32 A, the tests shall be based on this rated
current.
5.6 Lampholders are deemed to comply with this standard if no specimen fails in the
complete series of tests specified in 5.3.
If one specimen fails in one test, that test and the preceding ones which may have influenced
the result of that test are repeated on another set of specimens to the number required by
5.3, all of which shall then comply with the repeated tests and with the subsequent tests.
Lampholders are deemed not to comply with this standard if there are more failures than one.
6 Standard ratings
6.1 Standard rated voltages are 250 V and 500 V.

For lampholders E14, and for switched lampholders E27, a rated voltage of 250 V only is
allowed.
For lampholders E5 and E10 intended for the connection of series-connected lamps to the
supply, the rated voltage shall not exceed 25 V for lampholders E5 and not exceed 60 V for
lampholders E10.
NOTE 1 These values refer to the voltage between parts of different polarity.
For lampholders E10 intended for the connection of single lamps to the supply, a rated
voltage of 250 V only is allowed.
NOTE 2 These lampholders are also used for such special cases as series-connected lamps, where, because of
the low number of lamps, 60 V per lampholder is exceeded.
With the exception given for lampholders E5 and E10, the rated voltage shall be not less than
250 V. Additionally a rated voltage of 125 V is allowed for lampholders E40.
Compliance is checked by inspection of the marking.
6.2 Standard rated currents are
– 0,2 A for lampholders E5;
– 0,5 A for lampholders E10;
– 2 A for lampholders E14;
– 2 A for switched-lampholders E27;
– 4 A for other lampholders E27;
– 16 A for lampholders E40.
The rated current shall be not less than the standard value.
Compliance is checked by inspection of the marking.
6.3 Lampholders E40 to be used on 125 V installations may have an additional nominal
rating of 32 A.
NOTE This nominal rating covers the voltages up to and including 130 V.
Compliance is checked by inspection of the marking.
6.4 The rated operating temperature for lampholders intended for use in high temperature
conditions (T marked holders) shall be not lower than 140 °C for lampholders E14, not lower
than 170 °C for lampholders E27 and not lower than 230 °C for lampholders E40.
Compliance is checked by inspection of the marking.
NOTE The rated operating temperatures for Edison screw lampholders without T marking are given in IEC 60598-1,
Table 12.1. They are
– 135 °C for lampholders E14;
– 165 °C for lampholders E27;
– 225 °C for lampholders E40.
7 Classification
Lampholders are classified as defined in 7.1 to 7.6.

– 14 – IEC 60238:2016 © IEC 2016
7.1 According to the material of the external parts:
– lampholders of insulating material;
– metal lampholders.
NOTE Lampholders with external parts consisting partly of metal and lampholders comprising external parts of
insulating material with a conductive outer surface, for example a metallized outer shell, are considered as metal
lampholders (see 13.3). This does not apply to threaded entries and external parts, for example a metal shade ring
mounted onto the outside of a lampholder of insulating material, which cannot become live even in the case of an
insulation fault. Metal holders with insulating coverings are considered as metal lampholders (see 10.5).
In order to check whether or not a surface is conductive, two stripe-electrodes 1,5 mm wide,
25 mm long and with a distance of 2 mm from each other are applied to the surface (e.g. with
silver conductive paint). In accordance with 15.4, the insulating resistance is measured
between the stripes. The surface is considered to be conductive if the resistance is less than
5 MΩ.
7.2 According to degree of protection against ingress of water:
– ordinary lampholders;
– drip-proof lampholders.
7.3 According to method of fixing:
– threaded entry lampholders;
– cord-grip lampholders;
– backplate lampholders;
– other lampholders.
NOTE Examples of other lampholders are lampholders provided with a mechanical suspension device, e.g. a
hook.
7.4 According to type:
– switched-lampholders, provided with an integral switch to control the supply to the lamp;
– non-switched lampholders.
7.5 According to protection against electric shock:
– unenclosed lampholders;
– enclosed lampholders;
– independent lampholders;
– partly reinforced insulated lampholders;
– enclosed reinforced insulated lampholders.
NOTE Where a lampholder is used with a working voltage of 50 % or less of its maximum rating, it can be
regarded as equivalent to a reinforced insulated lampholder.
7.6 According to resistance to heat:
– lampholders for rated operating temperatures up to the limits given in 6.4;
– lampholders for operating in high temperature conditions (T marked holders).
8 Marking
8.1 Lampholders, other than lampholders E5 and E10, shall be marked with the following:
– rated current, in amperes;
– rated voltage, in volts, and rated pulse voltage, in kV, if higher than

• 2,5 kV for lampholders rated 250 V,
• 4 kV for lampholders rated 500 V;
The rated pulse voltage of the lampholder (in kV) should either be marked on the
lampholder or made available in the manufacturer’s catalogue or the like.
NOTE 1 Some lampholders still show rated voltages higher than 500 V. This is an earlier way of expressing
the permissible pulse voltage via a rated voltage. For such lampholders, the creepage distances and
clearances can be found in IEC 60598-1.
– symbol for nature of current, if required (for switched lampholders only);
– mark of origin (this may take the form of a trade mark, manufacturer's identification mark
or the name of the responsible vendor);
– type reference;
Available technical documentation of the manufacturer like printed catalogues or online
catalogues should allow a clear identification of a lampholder either by a unique catalogue
number or by an identifying reference on the holder, specifying the essential
characteristic features and the basic design of the product supplemented by a clear
description. Variations of the basic design like for example different cable length, fixing
means, colours etc., which do not affect safety or performance of the lampholder, can be
disregarded in the type reference marked on the product. Variations included in the type
testing procedure are listed in the corresponding test reports.
– the degree of protection against ingress of water for drip-proof lampholders (see 8.2);
– rated operating temperature "T", indicating the highest operating temperature, if
applicable.
The marking of the rated operating temperature is not required for lampholders whose
exterior is made wholly of ceramic material. For these lampholders, this information, if
applicable, shall either be marked on the lampholder or be made available in the manu-
facturer's catalogue.
For lampholders according to this standard, the distances for impulse withstand category II
are usually applicable. For holders in equipment where a higher degree of availability is
expected,
...

IEC 60238 ®
Edition 9.2 2020-01
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
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Edison screw lampholders
Douilles à vis edison pour lampes

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IEC 60238 ®
Edition 9.2 2020-01
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Edison screw lampholders
Douilles à vis edison pour lampes

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.140.10 ISBN 978-2-8322-7771-3

IEC 60238 ®
Edition 9.2 2020-01
CONSOLIDATED VERSION
REDLINE VERSION
VERSION REDLINE
colour
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Edison screw lampholders
Douilles à vis edison pour lampes

– 2 – IEC 60238:2016+AMD1:2017
+AMD2:2020 CSV © IEC 2020
CONTENTS
FOREWORD . 4
INTRODUCTION to Amendment 2 . 6
1 Scope . 7
2 Normative references . 8
3 Terms and definitions . 9
4 General requirement . 14
5 General conditions for tests . 14
6 Standard ratings . 15
7 Classification . 16
8 Marking . 17
9 Dimensions. 19
10 Protection against electric shock . 22
11 Terminals . 24
12 Provision for earthing . 28
13 Construction . 29
14 Switched lampholders . 34
15 Moisture resistance, insulation resistance and electric strength . 35
16 Mechanical strength . 37
17 Screws, current-carrying parts and connections . 41
18 Creepage distances and clearances . 43
19 Normal operation . 50
20 General resistance to heat . 51
21 Resistance to heat, fire and tracking . 54
22 Resistance to excessive residual stresses (season cracking) and to rusting . 56
Annex A (normative) Season cracking/corrosion test . 77
Annex B (informative) Guidance for requirements in IEC 61058-1 applicable to
switches in lampholders (see 14.2) . 79
Annex C (informative) Guidance for special requirements in appliance standards –
Household and similar electrical appliances . 81
Annex D (informative) Schedule of amended subclauses containing more
serious/critical requirements which require products to be retested Clauses containing
new or more stringent requirements with respect to the previous edition . 83
Bibliography . 84

Figure 1a –Nipple thread for lampholders: metric thread. Basic profile and design
profile for the nut and for the screw . 57
Figure 1b –Nipple thread for lampholders: ISO standard pipe thread. Basic profile and
design profile for the nut and for the screw . 58
Figure 2a – Gauges for metric thread for nipples . 59
Figure 2b – Gauges for ISO standard pipe thread for nipples . 60
Figure 3 – Gauge for holes for backplate lampholder screws . 61
Figure 4 – Normal operation test apparatus . 62
Figure 5 – Test caps for the test of Clause 18 . 63

+AMD2:2020 CSV © IEC 2020
Figure 6 – Torque apparatus . 64
Figure 7 – Tumbling barrel . 65
Figure 8 – Impact-test apparatus . 66
Figure 9 – Pressure apparatus . 67
Figure 10 – Ball-pressure test apparatus. 67
Figure 11 – Test cap for the tests of 15.4 and 20.3 . 68
Figure 12 – Bending apparatus . 69
Figure 13 – Test cap A and test cap B for lampholders E14 (2 of 2) . 71
Figure 14 – Test cap for lampholders E27 . 72
Figure 15 – Test cap for lampholders E40 . 73
Figure 16 – Standard test finger (according to IEC 60529) . 74
Figure 17 – Clarification of some definitions . 75
Figure 18 – Preparation of specimens for the needle-flame test of 21.4 . 76

Table 1 – Thickness of screw shells and contacts . 20
Table 2 – Minimum effective screw lengths . 21
Table 3 – Dimensions of threaded entries and set screws . 22
Table 4 – Minimum dimensions of pillar-type terminals . 26
Table 5 – Minimum dimensions of screw-type terminals . 26
Table 6 – Pull and torque values . 32
Table 7 – Insertion torque . 34
Table 8 – Minimum and maximum removal torques . 34
Table 9 – Test cap dimensions . 38
Table 10 – Heights of fall . 39
Table 11 – Maximum deformation values . 41
Table 12 – Torque values . 42
Table 13a – Minimum distances for AC (50/60 Hz) sinusoidal voltages up to 30 kHz −
Impulse withstand category II . 45
Table 13b – Minimum distances for AC (50/60 Hz) sinusoidal voltages up to 30 kHz −
Impulse withstand category III . 47
Table 14 – Minimum distances for non-sinusoidal ignition pulse voltages or equivalent
peak voltages Up . 50
Table 15 – Heating cabinet temperatures . 53
Table A.1 – pH adjustment . 77

– 4 – IEC 60238:2016+AMD1:2017
+AMD2:2020 CSV © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EDISON SCREW LAMPHOLDERS
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
This consolidated version of the official IEC Standard and its amendments has been
prepared for user convenience.
IEC 60238 edition 9.2 contains the ninth edition (2016-07) [documents 34B/1852/FDIS
and 34B/1860/RVD], and its amendment 1 (2017-01) [documents 34B/1887/FDIS and
34B/1892/RVD] and its corrigendum (2018-01), and its amendment 2 (2020-01)
[documents 34B/2029/CDV and 34B/2040A/RVC].
In this Redline version, a vertical line in the margin shows where the technical content
is modified by amendments 1 and 2. Additions are in green text, deletions are in
strikethrough red text. A separate Final version with all changes accepted is available
in this publication.
+AMD2:2020 CSV © IEC 2020
International Standard IEC 60238 has been prepared by subcommittee 34B: Lamp caps and
holders, of IEC technical committee 34: Lamps and related equipment.
This ninth edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Addition of a pull test for certain E5 and E10 lampholders.
b) Annex D listing amended requirements/clauses which require products to be retested.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
In this standard, the following print types are used:
– compliance statements: in italic type.
The committee has decided that the contents of the base publication and its amendments will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 6 – IEC 60238:2016+AMD1:2017
+AMD2:2020 CSV © IEC 2020
INTRODUCTION to Amendment 2
Some changes and corrections needed for IEC 60238 became obvious during the work
relating to the consolidated Edition 9.1 of IEC 60238.
Change 1:
Actual lamp holder safety standards require a ball pressure test in line with IEC 60695-10-2 in
sections “Resistance to heat, fire and tracking”. Within this test there is an alternative depth
indentation method described for the calculation of the indentation diameter.
This alternative calculation option was removed from the latest edition of IEC 60695-10-2
dated 2014 and during its meeting held in Sydney in 2018, SC 34B/WG1 agreed to delete the
alternative method as well from IEC 60238.
Change 2:
Based on IEC 60664-1:2007, 4.8.1.5 "Non tracking materials":
"For glass, ceramics or other inorganic insulating materials which do not track, creepage
distances need not be greater than their associated clearance for the purpose of insulation
coordination. The dimensions of Table F.2 for inhomogeneous field conditions are
appropriate."
This is not completely reflected in TC 34 standards as revised recently. For applications with
ELV it is of high importance whether the creepage distance shall be 0,6 mm or may be
0,2 mm in the case where inorganic insulating material is used.
Correction
In Amendment 1 to IEC 60238 Edition 9, a complete paragraph was deleted by accident. This
was corrected with the publication of a corrigendum to Amendment 1, however an editorial
correction needs to be made to the references to previous items, changed to table footnotes
"a" and "d", as the referenced text was included in Tables 13a and 13b.

+AMD2:2020 CSV © IEC 2020
EDISON SCREW LAMPHOLDERS
1 Scope
This International Standard applies to lampholders with Edison thread E14, E27 and E40,
designed for connection to the supply of lamps and semi-luminaires only.
It also applies to switched-lampholders for use in AC circuits only, where the working voltage
does not exceed 250 V r.m.s.
This standard also applies to lampholders with Edison thread E5 designed for connection to
the supply mains of series connected lamps, with a working voltage not exceeding 25 V, to be
used indoors, and to lampholders with Edison thread E10 designed for connection to the
supply mains of series connected lamps, with a working voltage not exceeding 60 V, to be
used indoors or outdoors. It also applies to lampholders E10 for building-in, for the connection
of single lamps to the supply. These lampholders are not intended for retail sale.
As far as it reasonably applies, this standard also covers lampholders other than lampholders
with Edison thread designed for connection of series-connected lamps to the supply.
NOTE This type of lampholder is for example used in Christmas tree lighting chains.
As far as it reasonably applies, this standard also covers adapters.
This standard also covers lampholders which are, wholly or partly, integral with a luminaire or
intended to be built into appliances. It covers the requirements for the lampholder only. For all
other requirements, such as protection against electric shock in the area of the terminals or of
the lamp cap, the requirements of the relevant appliance standard are observed and tested
after building into the appropriate equipment, when that equipment is tested according to its
own standard. Such lampholders as well as lampholders provided with a snap-on outer shell,
for use by luminaire manufacturers only, are not for retail sale.
This standard applies to lampholders to be used indoors or outdoors in residential as well as
in industrial lighting installations. It also applies to candle lampholders. In locations where
special conditions prevail, as for street lighting, on board ships, in vehicles and in hazardous
locations, for example where explosions are liable to occur, special constructions may be
required.
This standard does not apply to three-light lampholders E26d.
This standard is based on the following data relative to lamps for general lighting service:
– caps E14 are used for lamps with a current not exceeding 2 A;
– caps E27 are used for lamps with a current not exceeding 4 A;
– caps E40 are used for lamps with a current not exceeding 16 A, or 32 A if the nominal
voltage of the supply does not exceed 130 V (see 5.5 and 6.3).
Where lampholders are used in luminaires, their maximum operating temperatures are
specified in IEC 60598.
___________
Requirements for lampholders suitable for semi-luminaires are under consideration.

– 8 – IEC 60238:2016+AMD1:2017
+AMD2:2020 CSV © IEC 2020
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60061-1, Lamp caps and holders together with gauges for the control of
interchangeability and safety – Part 1: Lamp caps
IEC 60061-2, Lamp caps and holders together with gauges for the control of
interchangeability and safety – Part 2: Lampholders
IEC 60061-3, Lamp caps and holders together with gauges for the control of
interchangeability and safety – Part 3: Gauges
IEC 60068-2-32:1975, Basic environmental testing procedures – Part 2-32: Tests – Test Ed:
Free fall
IEC 60068-2-75:2014, Environmental testing – Part 2-75: Tests – Test Eh: Hammer tests
IEC 60112:2003, Method for the determination of the proof and the comparative tracking
indices of solid insulating materials
Amendment 1:2009
IEC 60227 (all parts), Polyvinyl chloride insulated cables of rated voltages up to and including
450/750 V
IEC 60245 (all parts), Rubber insulated cables – Rated voltages up to and including
450/750 V
IEC 60352-1:1997, Solderless connections – Part 1: Wrapped connections – General
requirements, test methods and practical guidance
IEC 60399, Barrel thread for lampholders with shade holder ring
IEC 60417, Graphical symbols for use on equipment (available at: http://www.graphical-
symbols.info/equipment)
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
Amendment 1:1999
Amendment 2:2013
IEC 60598-1, Luminaires – Part 1: General requirements and tests
IEC 60630, Maximum lamp outlines for incandescent lamps
IEC 60695-2-11:2014, Fire hazard testing – Part 2-11: Glowing/hot-wire based test methods –
Glow-wire flammability test method for end-products (GWEPT)
IEC 60695-11-5, Fire hazard testing – Part 11-5: Test flames – Needle-flame test method –
Apparatus, confirmatory test arrangement and guidance
___________
A consolidated edition 2.2 (2013) exists including edition 2.0 (1989) and its Amendment 1 (1999) and
Amendment 2 (2013).
+AMD2:2020 CSV © IEC 2020
IEC 61058-1:2000, Switches for appliances – Part 1: General requirements
ISO 4046-4:2002, Paper, board, pulps and related terms – Vocabulary – Part 4: Paper and
board grades and converted products
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
cord-grip lampholder
lampholder incorporating a method of retaining a flexible cord by which it may then be
suspended
3.2
threaded entry lampholder
lampholder incorporating a threaded component at the point of entry of the supply wires
permitting the lampholder to be mounted on a mating threaded support
Note 1 to entry: A threaded entry lampholder was formerly called a “nipple lampholder”.
3.3
backplate lampholder
lampholder so designed as to be suitable for mounting by means of an associated or integral
backplate, directly onto a supporting surface or appropriate box
3.4
lampholder for building-in
lampholder designed to be built into a luminaire, an additional enclosure or the like
3.4.1
unenclosed lampholder
lampholder for building-in so designed that it requires additional means, for example an
enclosure, to meet the requirements of this standard with regard to protection against electric
shock
3.4.2
enclosed lampholder
lampholder for building-in so designed that on its own it fulfils the requirements of this
standard with regard to protection against electric shock and IP classification, if appropriate
3.5
independent lampholder
lampholder so designed that it can be mounted separately from a luminaire and at the same
time providing all the necessary protection according to its classification and marking
3.6
terminal/contact assembly
part or assembly of parts which provides a means of connection between the termination of a
supply conductor and the contact making surfaces of the corresponding lamp cap
Note 1 to entry: For clarification of some definitions, see also Figure 17.
3.7
outer shell
cylindrical component protecting the user from contact with the lamp cap.
Note 1 to entry: It may or may not be provided with an external screw thread for fixing a shade ring.

– 10 – IEC 60238:2016+AMD1:2017
+AMD2:2020 CSV © IEC 2020
Note 2 to entry: For clarification of some definitions, see also Figure 17.
3.7.1
snap-on outer shell
outer shell for screwless assembly which does not contain the screw shell
Note 1 to entry: The lampholder should not be used when the snap-on outer shell is removed. It is therefore
recommended to place an approval mark, if provided, in such a way that it is not visible when this type of outer
shell is removed.
3.8
screw shell
cylindrical component having an internal screw thread of Edison form for the retention of the
corresponding lamp (cap)
Note 1 to entry: In some constructions, the screw shell is permanently fixed to or integral with the outer shell.
Note 2 to entry: For clarification of some definitions, see also Figure 17.
3.9
insulating ring
cylindrical intermediate piece of insulating material separating a metal screw shell and a metal
outer shell
Note 1 to entry: For clarification of some definitions, see also Figure 17.
3.10
shade ring
cylindrical component having an internal thread or other means to engage a corresponding
support on the outer shell and intended to carry or retain a shade
Note 1 to entry: For clarification of some definitions, see also Figure 17.
3.11
dome
part of a cord-grip lampholder or threaded entry lampholder which shields the connecting
terminals
Note 1 to entry: For clarification of some definitions, see also Figure 17.
3.12
basic insulation
insulation applied to live parts to provide basic protection against electric shock
Note 1 to entry: Basic insulation does not necessarily include insulation used exclusively for functional purposes.
3.13
supplementary insulation
independent insulation applied in addition to basic insulation in order to provide protection
against electric shock in the event of a failure of basic insulation
3.14
double insulation
insulation comprising both basic insulation and supplementary insulation
3.15
reinforced insulation
single insulation system applied to live parts, which provides a degree of protection against
electric shock equivalent to double insulation under the conditions specified
Note 1 to entry: The term "insulation system" does not imply that the insulation is one homogeneous piece. It may
comprise several layers which cannot be tested singly as supplementary or basic insulation.

+AMD2:2020 CSV © IEC 2020
3.16
live part
conductive part which may cause an electric shock
3.17
type test
test or series of tests made on a type test sample, for the purpose of checking compliance of
the design of a given product with the requirements of the relevant standard
3.18
type test sample
sample consisting of one or more similar specimens submitted by the manufacturer or
responsible vendor for the purpose of a type test
3.19
semi-luminaire
unit similar to a self-ballasted lamp but designed to utilize a replaceable light source and/or
starting device
3.20
rated operating temperature
highest temperature for which the holder is designed
3.21
rated minimum temperature
lowest temperature for which the holder is designed (applicable only to lampholders intended
for use in refrigerators and food freezers)
3.22
angled lampholder
lampholder, the rear side of which (threaded entry and/or dome) is at an angled position to
the screw shell axis
3.23
lampholder with retention device
lampholder with a device intended to prevent the lamp from becoming loose in the holder
Note 1 to entry: Lamps can, for example, become loose due to changes in temperature or to vibrations.
3.24
impulse withstand category
numeral defining a transient overvoltage condition
Note 1 to entry: Impulse withstand categories I, II, III and IV are used.
a) Purpose of classification of impulse withstand categories
Impulse withstand categories are to distinguish different degrees of availability of equipment with regard to
required expectations on continuity of service and on an acceptable risk of failure.
By selection of impulse withstand levels of equipment insulation, co-ordination can be achieved in the whole
installation, reducing the risk of failure to an acceptable level providing a basis for overvoltage control.
A higher characteristic numeral of an impulse withstand category indicates a higher specific impulse withstand
of the equipment and offers a wider choice of methods for overvoltage control.
The concept of impulse withstand category is used for equipment energized directly from the mains.
b) Description of impulse withstand categories
Equipment of impulse withstand category I is equipment which is intended to be connected to the fixed
electrical installations of buildings. Protective means are taken outside the equipment – either in the fixed
installation or between the fixed installation and the equipment – to limit transient overvoltages to the specific
level.
Equipment of impulse withstand category II is equipment to be connected to the fixed electrical installations of
buildings.
– 12 – IEC 60238:2016+AMD1:2017
+AMD2:2020 CSV © IEC 2020
Equipment of impulse withstand category III is equipment which is part of the fixed electrical installations and
other equipment where a higher degree of availability is expected.
Equipment of impulse withstand category IV is for use at or in the proximity of the origin of the electrical
installations of buildings upstream of the main distribution board.
3.25
primary circuit
circuit which is directly connected to the AC mains supply
Note 1 to entry: It includes, for example, the means for connection to the AC mains supply, the primary windings
of transformers, motors and other loading devices.
3.26
secondary circuit
circuit which has no direct connection to a primary circuit and derives its power from a
transformer, converter or equivalent isolation device, or from a battery
Note 1 to entry: Exception: autotransformers. Although having direct connection to a primary circuit, the tapped
part of them is also deemed to be a secondary circuit in the sense of this definition.
Note 2 to entry: Mains transients in such a circuit are attenuated by the corresponding primary windings. Also
inductive ballasts reduce the mains transient voltage height. Therefore, components located after a primary circuit
or after an inductive ballast can be suited for an impulse withstand category of one step lower, i.e. for impulse
withstand category II.
3.27
adapter
component used for the electrical and mechanical connection of a lamp to a lampholder
Note 1 to entry: This definition is specific for this standard. The definition of an adapter in principle could vary
very much depending on its use. In most cases such a component is used to bridge differences in the screw thread
diameter between the lampholder and the lamp.
3.28
enclosed reinforced insulated lampholder
lampholder for building-in so designed that on its own it fulfils the requirements for double or
reinforced insulated parts in class II applications
3.29
partly reinforced insulated lampholder
lampholder for building-in so designed that some parts of the lampholder require additional
means to fulfil the requirements with regard to double or reinforced insulation
Note 1 to entry: In some cases, the dimensions might be achieved only after mounting into the luminaire.
3.30
rated voltage
voltage declared by the manufacturer to indicate the highest working voltage for which the
lampholder is intended
[SOURCE: IEC 60838-1:2016, 3.1]
3.31
working voltage
highest r.m.s. voltage that may occur across any insulation, transients being disregarded,
both when the lamp is operating under normal conditions and when the lamp is removed
[SOURCE: IEC 60838-1:2016, 3.2]

+AMD2:2020 CSV © IEC 2020
3.32
rated current
current declared by the manufacturer to indicate the highest current for which the lampholder
is intended
[SOURCE: IEC 60838-1:2016, 3.3]
3.33
critical frequency
ƒ
crit
frequency at which the reduction of the breakdown voltage of a clearance begins (occurs)
Note 1 to entry: ƒ ≈ 0,2/d [MHz] where d (in mm) is the clearance according to Table 3 (basic or supplementary
crit
insulation and reinforced insulation respectively) disregarding the frequency.
[SOURCE: IEC 61347-1:2015, 3.40, modified – the note has been added]
3.34
ignition voltage
peak voltage applied to ignite a discharge lamp
[SOURCE: IEC 61347-1:2015, 3.46]
3.34.1
ignition pulse voltage
peak ignition voltage with a total duration of ≤ 750 µs (summation of all pulses durations)
within 10 ms, with the duration time (width) of each pulse being measured at the level of 50 %
of the maximum absolute peak value
Note 1 to entry: Ignition pulse waveforms, which are considered as ignition pulse voltage, should not contain any
dominant frequency above 30 kHz or should be usually highly damped (after 20 μs the peak voltage level should be
less than one half of the maximum peak voltage). For the assessment of the dominant frequency IEC 60664-
4:2005, Annex E should be consulted.
[SOURCE: IEC 61347-1:2015, 3.46.1]
3.35
rated ignition voltage
highest peak value of an ignition pulse voltage the holder is able to withstand
3.36
maximum working voltage
U
out
maximum occurring working voltage (r.m.s.) between the output terminals of a controlgear or
between the output terminals and earth, during normal or abnormal operating condition
Note 1 to entry: Transients and ignition voltages have to be neglected.
[SOURCE: IEC 61347-1:2015, 3.33, modified – "of a controlgear" has been added]
3.37
maximum working peak output voltage
Û
out
maximum repetitive occurring peak working voltage between the output terminals of a
controlgear or between its output terminals and earth, during normal or abnormal operating
condition and with transients neglected
[SOURCE: IEC 61347-1:2015, 3.45, modified – "of a controlgear" has been added]

– 14 – IEC 60238:2016+AMD1:2017
+AMD2:2020 CSV © IEC 2020
3.38
equivalent transformed peak voltage
U
p
transformed output peak voltage, which is converted for the worst case peak voltage with its
related frequency into an ignition pulse voltage
Note 1 to entry: The value of the declared equivalent transformed output peak voltage is the essential parameter
for selecting the associated components.
Note 2 to entry: See 3.34.1.
Note 3 to entry: To determine the declared equivalent transformed output peak voltage for basic insulation U
p
[basic] the worst case combination of the maximum occurring peak voltage and frequency has to be taken into
account, which means the maximum clearance according to IEC 61347-1:2015, Table 10 for basic insulation.
Note 4 to entry: To determine the declared equivalent transformed output peak voltage for the reinforced
insulation U [reinforced] the worst case combination of the maximum occurring peak voltage and frequency has to
p
be taken into account, which means the maximum clearance according to IEC 61347-1:2015, Table 11 for
reinforced insulation.
[SOURCE: IEC 61347-1:2015, 3.47]
4 General requirement
Lampholders shall be so designed and constructed that in normal use they function reliably
and cause no danger to persons or surroundings.
In general, compliance is checked by carrying out all the tests specified.
In addition, the enclosure of independent lampholders shall comply with the requirements of
IEC 60598-1, including the classification and marking requirements of that standard.
5 General conditions for tests
5.1 Tests according to this standard are type tests.
NOTE The requirements and tolerances permitted by this standard are related to testing of a type test sample
submitted for that purpose.
Compliance of the type test sample does not ensure compliance of the whole production of a manufacturer with this
safety standard.
In addition to type testing, conformity of production is the responsibility of the manufacturer and can include routine
tests and quality assurance.
For further information on conformity testing during manufacture see IEC 60061-4.
5.2 Unless otherwise specified, the tests are made at an ambient temperature of 20 °C ±
5 °C and with the holder tested as delivered and installed as in normal use.
5.3 The tests and inspections are carried out on a total of
– nine specimens for non-switched lampholders, or
– 12 specimens for switched lampholders
in the following order of clauses:
– three specimens: Clauses 2 to 13 (except for 10.1 and 11.2) and Clauses 15 to 18;
– three specimens: Clause 14 (switched-lampholder tests only);
– three specimens: 10.1 and Clauses 19 and 20;

+AMD2:2020 CSV © IEC 2020
– two specimens: Clause 21 (of which one specimen for the test of 21.1 and the other for
the tests of 21.3 or 21.4);
– one specimen: 21.5 and Clause 22.
For testing lampholders with a retention device, the retention device shall be removed.
For testing lampholders with a retention device according to 13.14, three additional
specimens are required with the retention device kept in place.
For testing of screwless terminals according to 11.2, separate specimens are required in
addition.
5.4 In case of doubt, gauges, test caps and mandrels are introduced into the specimens,
unless otherwise specified, by applying the following torques:
– 0,2 Nm for lampholders E5;
– 0,2 Nm for lampholders E10;
– 0,2 Nm for lampholders E14;
– 0,4 Nm for lampholders E27;
– 0,8 Nm for lampholders E40.
5.5 For lampholders E40 with a rated current of 32 A, the tests shall be based on this rated
current.
5.6 Lampholders are deemed to comply with this standard if no specimen fails in the
complete series of tests specified in 5.3.
If one specimen fails in one test, that test and the preceding ones which may have influenced
the result of that test are repeated on another set of specimens to the number required by 5.3,
all of which shall then comply with the repeated tests and with the subsequent tests.
Lampholders are deemed not to comply with this standard if there are more failures than one.
6 Standard ratings
6.1 Standard rated voltages are 2
...

IEC 60238 ®
Edition 9.1 2017-01
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Edison screw lampholders
Douilles à vis edison pour lampes

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IEC 60238 ®
Edition 9.1 2017-01
CONSOLIDATED VERSION
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Edison screw lampholders
Douilles à vis edison pour lampes

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.140.10 ISBN 978-2-8322-3918-6

IEC 60238 ®
Edition 9.1 2017-01
CONSOLIDATED VERSION
REDLINE VERSION
VERSION REDLINE
colour
inside
Edison screw lampholders
Douilles à vis edison pour lampes

– 2 – IEC 60238:2016+AMD1:2017 CSV
© IEC 2017
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 7
3 Terms and definitions. 8
4 General requirement . 13
5 General conditions for tests . 13
6 Standard ratings . 14
7 Classification . 15
8 Marking . 16
9 Dimensions . 18
10 Protection against electric shock . 21
11 Terminals . 23
12 Provision for earthing . 27
13 Construction . 28
14 Switched lampholders . 33
15 Moisture resistance, insulation resistance and electric strength . 34
16 Mechanical strength . 36
17 Screws, current-carrying parts and connections . 41
18 Creepage distances and clearances . 42
19 Normal operation . 49
20 General resistance to heat . 50
21 Resistance to heat, fire and tracking . 53
22 Resistance to excessive residual stresses (season cracking) and to rusting . 55
Annex A (normative) Season cracking/corrosion test . 76
Annex B (informative) Guidance for requirements in IEC 61058-1 applicable to switches
in lampholders (see 14.2) . 78
Annex C (informative) Guidance for special requirements in appliance standards –
Household and similar electrical appliances . 80
Annex D (informative) Schedule of amended subclauses containing more
serious/critical requirements which require products to be retested Clauses containing
new or more stringent requirements with respect to the previous edition . 82
Bibliography . 83

Figure 1a –Nipple thread for lampholders: metric thread. Basic profile and design profile
for the nut and for the screw . 56
Figure 1b –Nipple thread for lampholders: ISO standard pipe thread. Basic profile and
design profile for the nut and for the screw . 57
Figure 2a – Gauges for metric thread for nipples . 58
Figure 2b – Gauges for ISO standard pipe thread for nipples . 59
Figure 3 – Gauge for holes for backplate lampholder screws . 60
Figure 4 – Normal operation test apparatus . 61
Figure 5 – Test caps for the test of Clause 18 . 62
Figure 6 – Torque apparatus . 63

© IEC 2017
Figure 7 – Tumbling barrel . 64
Figure 8 – Impact-test apparatus . 65
Figure 9 – Pressure apparatus . 66
Figure 10 – Ball-pressure test apparatus . 66
Figure 11 – Test cap for the tests of 15.4 and 20.3 . 67
Figure 12 – Bending apparatus . 68
Figure 13 – Test cap A and test cap B for lampholders E14 (2 of 2) . 70
Figure 14 – Test cap for lampholders E27 . 71
Figure 15 – Test cap for lampholders E40 . 72
Figure 16 – Standard test finger (according to IEC 60529) . 73
Figure 17 – Clarification of some definitions . 74
Figure 18 – Preparation of specimens for the needle-flame test of 21.4 . 75

Table 1 – Thickness of screw shells and contacts . 19
Table 2 – Minimum effective screw lengths . 20
Table 3 – Dimensions of threaded entries and set screws . 21
Table 4 – Minimum dimensions of pillar-type terminals . 25
Table 5 – Minimum dimensions of screw-type terminals . 25
Table 6 – Pull and torque values . 31
Table 7 – Insertion torque . 33
Table 8 – Minimum and maximum removal torques . 33
Table 9 – Test cap dimensions . 37
Table 10 – Heights of fall. 38
Table 11 – Maximum deformation values . 40
Table 12 – Torque values . 41
Table 13a – Minimum distances for AC (50/60 Hz) sinusoidal voltages up to 30 kHz −
Impulse withstand category II . 44
Table 13b – Minimum distances for AC (50/60 Hz) sinusoidal voltages up to 30 kHz −
Impulse withstand category III . 46
Table 14 – Minimum distances for non-sinusoidal ignition pulse voltages or equivalent
peak voltages Up . 48
Table 15 – Heating cabinet temperatures . 51
Table A.1 – pH adjustment . 75

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© IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EDISON SCREW LAMPHOLDERS
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
This consolidated version of the official IEC Standard and its amendment has been prepared
for user convenience.
IEC 60238 edition 9.1 contains the ninth edition (2016-07) [documents 34B/1852/FDIS and
34B/1860/RVD], and its amendment 1 (2017-01) [documents 34B/1887/FDIS and 34B/1892/RVD]
and its corrigendum (2018-01).
In this Redline version, a vertical line in the margin shows where the technical content is
modified by amendment 1. Additions are in green text, deletions are in strikethrough red text. A
separate Final version with all changes accepted is available in this publication.

© IEC 2017
International Standard IEC 60238 has been prepared by subcommittee 34B: Lamp caps and
holders, of IEC technical committee 34: Lamps and related equipment.
This ninth edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Addition of a pull test for certain E5 and E10 lampholders.
b) Annex D listing amended requirements/clauses which require products to be retested.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
In this standard, the following print types are used:
– compliance statements: in italic type.
The committee has decided that the contents of the base publication and its amendment will
remain unchanged until the stability date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

– 6 – IEC 60238:2016+AMD1:2017 CSV
© IEC 2017
EDISON SCREW LAMPHOLDERS
1 Scope
This International Standard applies to lampholders with Edison thread E14, E27 and E40,
designed for connection to the supply of lamps and semi-luminaires only.
It also applies to switched-lampholders for use in AC circuits only, where the working voltage
does not exceed 250 V r.m.s.
This standard also applies to lampholders with Edison thread E5 designed for connection to the
supply mains of series connected lamps, with a working voltage not exceeding 25 V, to be used
indoors, and to lampholders with Edison thread E10 designed for connection to the supply
mains of series connected lamps, with a working voltage not exceeding 60 V, to be used
indoors or outdoors. It also applies to lampholders E10 for building-in, for the connection of
single lamps to the supply. These lampholders are not intended for retail sale.
As far as it reasonably applies, this standard also covers lampholders other than lampholders
with Edison thread designed for connection of series-connected lamps to the supply.
NOTE This type of lampholder is for example used in Christmas tree lighting chains.
As far as it reasonably applies, this standard also covers adapters.
This standard also covers lampholders which are, wholly or partly, integral with a luminaire or
intended to be built into appliances. It covers the requirements for the lampholder only. For all
other requirements, such as protection against electric shock in the area of the terminals or of
the lamp cap, the requirements of the relevant appliance standard are observed and tested
after building into the appropriate equipment, when that equipment is tested according to its
own standard. Such lampholders as well as lampholders provided with a snap-on outer shell,
for use by luminaire manufacturers only, are not for retail sale.
This standard applies to lampholders to be used indoors or outdoors in residential as well as in
industrial lighting installations. It also applies to candle lampholders. In locations where special
conditions prevail, as for street lighting, on board ships, in vehicles and in hazardous locations,
for example where explosions are liable to occur, special constructions may be required.
This standard does not apply to three-light lampholders E26d.
This standard is based on the following data relative to lamps for general lighting service:
– caps E14 are used for lamps with a current not exceeding 2 A;
– caps E27 are used for lamps with a current not exceeding 4 A;
– caps E40 are used for lamps with a current not exceeding 16 A, or 32 A if the nominal
voltage of the supply does not exceed 130 V (see 5.5 and 6.3).
Where lampholders are used in luminaires, their maximum operating temperatures are
specified in IEC 60598.
___________
Requirements for lampholders suitable for semi-luminaires are under consideration.

© IEC 2017
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
IEC 60061-1, Lamp caps and holders together with gauges for the control of interchangeability
and safety – Part 1: Lamp caps
IEC 60061-2, Lamp caps and holders together with gauges for the control of interchangeability
and safety – Part 2: Lampholders
IEC 60061-3, Lamp caps and holders together with gauges for the control of interchangeability
and safety – Part 3: Gauges
IEC 60068-2-32:1975, Basic environmental testing procedures – Part 2-32: Tests – Test Ed:
Free fall
IEC 60068-2-75:2014, Environmental testing – Part 2-75: Tests – Test Eh: Hammer tests
IEC 60112:2003, Method for the determination of the proof and the comparative tracking
indices of solid insulating materials
Amendment 1:2009
IEC 60227 (all parts), Polyvinyl chloride insulated cables of rated voltages up to and including
450/750 V
IEC 60245 (all parts), Rubber insulated cables – Rated voltages up to and including 450/750 V
IEC 60352-1:1997, Solderless connections – Part 1: Wrapped connections – General
requirements, test methods and practical guidance
IEC 60399, Barrel thread for lampholders with shade holder ring
IEC 60417, Graphical symbols for use on equipment (available at: http://www.graphical-
symbols.info/equipment)
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
Amendment 1:1999
Amendment 2:2013
IEC 60598-1, Luminaires – Part 1: General requirements and tests
IEC 60630, Maximum lamp outlines for incandescent lamps
IEC 60695-2-11:2014, Fire hazard testing – Part 2-11: Glowing/hot-wire based test methods –
Glow-wire flammability test method for end-products (GWEPT)
IEC 60695-11-5, Fire hazard testing – Part 11-5: Test flames – Needle-flame test method –
Apparatus, confirmatory test arrangement and guidance
___________
A consolidated edition 2.2 (2013) exists including edition 2.0 (1989) and its Amendment 1 (1999) and
Amendment 2 (2013).
– 8 – IEC 60238:2016+AMD1:2017 CSV
© IEC 2017
IEC 61058-1:2000, Switches for appliances – Part 1: General requirements
ISO 4046-4:2002, Paper, board, pulps and related terms – Vocabulary – Part 4: Paper and
board grades and converted products
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
cord-grip lampholder
lampholder incorporating a method of retaining a flexible cord by which it may then be
suspended
3.2
threaded entry lampholder
lampholder incorporating a threaded component at the point of entry of the supply wires
permitting the lampholder to be mounted on a mating threaded support
Note 1 to entry: A threaded entry lampholder was formerly called a “nipple lampholder”.
3.3
backplate lampholder
lampholder so designed as to be suitable for mounting by means of an associated or integral
backplate, directly onto a supporting surface or appropriate box
3.4
lampholder for building-in
lampholder designed to be built into a luminaire, an additional enclosure or the like
3.4.1
unenclosed lampholder
lampholder for building-in so designed that it requires additional means, for example an
enclosure, to meet the requirements of this standard with regard to protection against electric
shock
3.4.2
enclosed lampholder
lampholder for building-in so designed that on its own it fulfils the requirements of this standard
with regard to protection against electric shock and IP classification, if appropriate
3.5
independent lampholder
lampholder so designed that it can be mounted separately from a luminaire and at the same
time providing all the necessary protection according to its classification and marking
3.6
terminal/contact assembly
part or assembly of parts which provides a means of connection between the termination of a
supply conductor and the contact making surfaces of the corresponding lamp cap
Note 1 to entry: For clarification of some definitions, see also Figure 17.
3.7
outer shell
cylindrical component protecting the user from contact with the lamp cap.

© IEC 2017
Note 1 to entry: It may or may not be provided with an external screw thread for fixing a shade ring.
Note 2 to entry: For clarification of some definitions, see also Figure 17.
3.7.1
snap-on outer shell
outer shell for screwless assembly which does not contain the screw shell
Note 1 to entry: The lampholder should not be used when the snap-on outer shell is removed. It is therefore
recommended to place an approval mark, if provided, in such a way that it is not visible when this type of outer shell
is removed.
3.8
screw shell
cylindrical component having an internal screw thread of Edison form for the retention of the
corresponding lamp (cap)
Note 1 to entry: In some constructions, the screw shell is permanently fixed to or integral with the outer shell.
Note 2 to entry: For clarification of some definitions, see also Figure 17.
3.9
insulating ring
cylindrical intermediate piece of insulating material separating a metal screw shell and a metal
outer shell
Note 1 to entry: For clarification of some definitions, see also Figure 17.
3.10
shade ring
cylindrical component having an internal thread or other means to engage a corresponding
support on the outer shell and intended to carry or retain a shade
Note 1 to entry: For clarification of some definitions, see also Figure 17.
3.11
dome
part of a cord-grip lampholder or threaded entry lampholder which shields the connecting
terminals
Note 1 to entry: For clarification of some definitions, see also Figure 17.
3.12
basic insulation
insulation applied to live parts to provide basic protection against electric shock
Note 1 to entry: Basic insulation does not necessarily include insulation used exclusively for functional purposes.
3.13
supplementary insulation
independent insulation applied in addition to basic insulation in order to provide protection
against electric shock in the event of a failure of basic insulation
3.14
double insulation
insulation comprising both basic insulation and supplementary insulation
3.15
reinforced insulation
single insulation system applied to live parts, which provides a degree of protection against
electric shock equivalent to double insulation under the conditions specified

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© IEC 2017
Note 1 to entry: The term "insulation system" does not imply that the insulation is one homogeneous piece. It may
comprise several layers which cannot be tested singly as supplementary or basic insulation.
3.16
live part
conductive part which may cause an electric shock
3.17
type test
test or series of tests made on a type test sample, for the purpose of checking compliance of
the design of a given product with the requirements of the relevant standard
3.18
type test sample
sample consisting of one or more similar specimens submitted by the manufacturer or
responsible vendor for the purpose of a type test
3.19
semi-luminaire
unit similar to a self-ballasted lamp but designed to utilize a replaceable light source and/or
starting device
3.20
rated operating temperature
highest temperature for which the holder is designed
3.21
rated minimum temperature
lowest temperature for which the holder is designed (applicable only to lampholders intended
for use in refrigerators and food freezers)
3.22
angled lampholder
lampholder, the rear side of which (threaded entry and/or dome) is at an angled position to the
screw shell axis
3.23
lampholder with retention device
lampholder with a device intended to prevent the lamp from becoming loose in the holder
Note 1 to entry: Lamps can, for example, become loose due to changes in temperature or to vibrations.
3.24
impulse withstand category
numeral defining a transient overvoltage condition
Note 1 to entry: Impulse withstand categories I, II, III and IV are used.
a) Purpose of classification of impulse withstand categories
Impulse withstand categories are to distinguish different degrees of availability of equipment with regard to
required expectations on continuity of service and on an acceptable risk of failure.
By selection of impulse withstand levels of equipment insulation, co-ordination can be achieved in the whole
installation, reducing the risk of failure to an acceptable level providing a basis for overvoltage control.
A higher characteristic numeral of an impulse withstand category indicates a higher specific impulse withstand
of the equipment and offers a wider choice of methods for overvoltage control.
The concept of impulse withstand category is used for equipment energized directly from the mains.
b) Description of impulse withstand categories
Equipment of impulse withstand category I is equipment which is intended to be connected to the fixed
electrical installations of buildings. Protective means are taken outside the equipment – either in the fixed

© IEC 2017
installation or between the fixed installation and the equipment – to limit transient overvoltages to the specific
level.
Equipment of impulse withstand category II is equipment to be connected to the fixed electrical installations of
buildings.
Equipment of impulse withstand category III is equipment which is part of the fixed electrical installations and
other equipment where a higher degree of availability is expected.
Equipment of impulse withstand category IV is for use at or in the proximity of the origin of the electrical
installations of buildings upstream of the main distribution board.
3.25
primary circuit
circuit which is directly connected to the AC mains supply
Note 1 to entry: It includes, for example, the means for connection to the AC mains supply, the primary windings
of transformers, motors and other loading devices.
3.26
secondary circuit
circuit which has no direct connection to a primary circuit and derives its power from a
transformer, converter or equivalent isolation device, or from a battery
Note 1 to entry: Exception: autotransformers. Although having direct connection to a primary circuit, the tapped
part of them is also deemed to be a secondary circuit in the sense of this definition.
Note 2 to entry: Mains transients in such a circuit are attenuated by the corresponding primary windings. Also
inductive ballasts reduce the mains transient voltage height. Therefore, components located after a primary circuit
or after an inductive ballast can be suited for an impulse withstand category of one step lower, i.e. for impulse
withstand category II.
3.27
adapter
component used for the electrical and mechanical connection of a lamp to a lampholder
Note 1 to entry: This definition is specific for this standard. The definition of an adapter in principle could vary very
much depending on its use. In most cases such a component is used to bridge differences in the screw thread
diameter between the lampholder and the lamp.
3.28
enclosed reinforced insulated lampholder
lampholder for building-in so designed that on its own it fulfils the requirements for double or
reinforced insulated parts in class II applications
3.29
partly reinforced insulated lampholder
lampholder for building-in so designed that some parts of the lampholder require additional
means to fulfil the requirements with regard to double or reinforced insulation
Note 1 to entry: In some cases, the dimensions might be achieved only after mounting into the luminaire.
3.30
rated voltage
voltage declared by the manufacturer to indicate the highest working voltage for which the
lampholder is intended
[SOURCE: IEC 60838-1:2016, 3.1]
3.31
working voltage
highest r.m.s. voltage that may occur across any insulation, transients being disregarded, both
when the lamp is operating under normal conditions and when the lamp is removed
[SOURCE: IEC 60838-1:2016, 3.2]

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© IEC 2017
3.32
rated current
current declared by the manufacturer to indicate the highest current for which the lampholder is
intended
[SOURCE: IEC 60838-1:2016, 3.3]
3.33
critical frequency
ƒ
crit
frequency at which the reduction of the breakdown voltage of a clearance begins (occurs)
Note 1 to entry: ƒ ≈ 0,2/d [MHz] where d (in mm) is the clearance according to Table 3 (basic or supplementary
crit
insulation and reinforced insulation respectively) disregarding the frequency.
[SOURCE: IEC 61347-1:2015, 3.40, modified – the note has been added]
3.34
ignition voltage
peak voltage applied to ignite a discharge lamp
[SOURCE: IEC 61347-1:2015, 3.46]
3.34.1
ignition pulse voltage
peak ignition voltage with a total duration of ≤ 750 µs (summation of all pulses durations) within
10 ms, with the duration time (width) of each pulse being measured at the level of 50 % of the
maximum absolute peak value
Note 1 to entry: Ignition pulse waveforms, which are considered as ignition pulse voltage, should not contain any
dominant frequency above 30 kHz or should be usually highly damped (after 20 μs the peak voltage level should be
less than one half of the maximum peak voltage). For the assessment of the dominant frequency IEC 60664-4:2005,
Annex E should be consulted.
[SOURCE: IEC 61347-1:2015, 3.46.1]
3.35
rated ignition voltage
highest peak value of an ignition pulse voltage the holder is able to withstand
3.36
maximum working voltage
U
out
maximum occurring working voltage (r.m.s.) between the output terminals of a controlgear or
between the output terminals and earth, during normal or abnormal operating condition
Note 1 to entry: Transients and ignition voltages have to be neglected.
[SOURCE: IEC 61347-1:2015, 3.33, modified – "of a controlgear" has been added]
3.37
maximum working peak output voltage
Û
out
maximum repetitive occurring peak working voltage between the output terminals of a
controlgear or between its output terminals and earth, during normal or abnormal operating
condition and with transients neglected
[SOURCE: IEC 61347-1:2015, 3.45, modified – "of a controlgear" has been added]

© IEC 2017
3.38
equivalent transformed peak voltage
U
p
transformed output peak voltage, which is converted for the worst case peak voltage with its
related frequency into an ignition pulse voltage
Note 1 to entry: The value of the declared equivalent transformed output peak voltage is the essential parameter
for selecting the associated components.
Note 2 to entry: See 3.34.1.
Note 3 to entry: To determine the declared equivalent transformed output peak voltage for basic insulation U
p
[basic] the worst case combination of the maximum occurring peak voltage and frequency has to be taken into
account, which means the maximum clearance according to IEC 61347-1:2015, Table 10 for basic insulation.
Note 4 to entry: To determine the declared equivalent transformed output peak voltage for the reinforced
insulation U [reinforced] the worst case combination of the maximum occurring peak voltage and frequency has to
p
be taken into account, which means the maximum clearance according to IEC 61347-1:2015, Table 11 for
reinforced insulation.
[SOURCE: IEC 61347-1:2015, 3.47]
4 General requirement
Lampholders shall be so designed and constructed that in normal use they function reliably and
cause no danger to persons or surroundings.
In general, compliance is checked by carrying out all the tests specified.
In addition, the enclosure of independent lampholders shall comply with the requirements of
IEC 60598-1, including the classification and marking requirements of that standard.
5 General conditions for tests
5.1 Tests according to this standard are type tests.
NOTE The requirements and tolerances permitted by this standard are related to testing of a type test sample
submitted for that purpose.
Compliance of the type test sample does not ensure compliance of the whole production of a manufacturer with this
safety standard.
In addition to type testing, conformity of production is the responsibility of the manufacturer and can include routine
tests and quality assurance.
For further information on conformity testing during manufacture see IEC 60061-4.
5.2 Unless otherwise specified, the tests are made at an ambient temperature of 20 °C ± 5 °C
and with the holder tested as delivered and installed as in normal use.
5.3 The tests and inspections are carried out on a total of
– nine specimens for non-switched lampholders, or
– 12 specimens for switched lampholders
in the following order of clauses:
– three specimens: Clauses 2 to 13 (except for 10.1 and 11.2) and Clauses 15 to 18;
– three specimens: Clause 14 (switched-lampholder tests only);
– three specimens: 10.1 and Clauses 19 and 20;

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© IEC 2017
– two specimens: Clause 21 (of which one specimen for the test of 21.1 and the other for the
tests of 21.3 or 21.4);
– one specimen: 21.5 and Clause 22.
For testing lampholders with a retention device, the retention device shall be removed.
For testing lampholders with a retention device according to 13.14, three additional specimens
are required with the retention device kept in place.
For testing of screwless terminals according to 11.2, separate specimens are required in
addition.
5.4 In case of doubt, gauges, test caps and mandrels are introduced into the specimens,
unless otherwise specified, by applying the following torques:
– 0,2 Nm for lampholders E5;
– 0,2 Nm for lampholders E10;
– 0,2 Nm for lampholders E14;
– 0,4 Nm for lampholders E27;
– 0,8 Nm for lampholders E40.
5.5 For lampholders E40 with a rated current of 32 A, the tests shall be based on this rated
current.
5.6 Lampholders are deemed to comply with this standard if no specimen fails in the complete
series of tests specified in 5.3.
If one specimen fails in one test, that test and the preceding ones which may have influenced
the result of that test are repeated on another set of specimens to the number required by 5.3,
all of which shall then comply with the repeated tests and with the subsequent tests.
Lampholders are deemed not to comply with this standard if there are more failures than one.
6 Standard ratings
6.1 Standard rated voltages are 250 V and 500 V.
For lampholders E14, and for switched lampholders E27, a rated voltage of 250 V only is
allowed.
For lampholders E5 and E10 intended for the connection of series-connected lamps to the
supply, the rated voltage shall not exceed 25 V for lampholders E5 and not exceed 60 V for
lampholders E10.
NOTE 1 These values refer to the voltage between parts of different polarity.
For lampholders E10 intended for the connection of single lamps to the supply, a rated voltage
of 250 V only is allowed.
NOTE 2 These lampholders are also used for such special cases as series-connected lamps, where, because of
the low number of lamps, 60 V per lampholder is exceeded.
With the exception given for lampholders E5 and E10, the rated voltage shall be not less than
250 V. Additionally a rated voltage of 125 V is allowed for lampholders E40.
Compliance is checked by inspection of the marking.

© IEC 2017
6.2 Standard rated currents are
– 0,2 A for lampholders E5;
– 0,5 A for lampholders E10;
– 2 A for lampholders E14;
– 2 A for switched-lampholders E27;
– 4 A for other lampholders E27;
– 16 A for lampholders E40.
The rated current shall be not less than the standard value.
Compliance is checked by inspection of the marking.
6.3 Lampholders E40 to be used on 125 V installations may have an additional nominal rating
of 32 A.
NOTE This nominal rating covers the voltages up to and
...