IEC 60238:2004

Edison screw lampholders

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 a.c. 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.

Douilles à vis Edison pour lampes

La présente Norme internationale 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 service ne dépasse pas 250 V (valeur efficace). La présente norme est également applicable aux douilles à vis Edison E5 destinées à être raccordées au réseau d'alimentation de lampes montées en série et dont la tension de fonctionnement ne dépasse pas 25 V, pour utilisation à l'intérieur, ainsi qu'aux douilles à vis Edison E10 destinées au raccordement au réseau d'alimentation de lampes montées en série et dont la tension de fonctionnement ne dépasse pas 60 V, pour utilisation à l'intérieur ou à l'extérieur. Elle s'applique également aux douilles E10 à incorporer, pour le raccordement de lampes individuelles à l'alimentation. Ces douilles ne sont pas destinées à la vente au détail.

General Information

• Status: Published
• Publication Date: 15-Jun-2011
• ICS: 29.140.10 - Lamp caps and holders
• Technical Committee: SC 34B - Lamp caps and holders
• Current Stage: DELPUB - Deleted Publication
• Start Date: 14-Jul-2016
• Completion Date: 26-Oct-2025

Relations

• Amended By: IEC 60238:2004/AMD1:2008 - Amendment 1 - Edison screw lampholders
• Effective Date: 05-Sep-2023
• Amended By: IEC 60238:2004/AMD2:2011 - Amendment 2 - Edison screw lampholders
• Effective Date: 05-Sep-2023
• Revises: IEC 60238:1998/AMD1:1999 - Amendment 1 - Edison screw lampholders
• Effective Date: 05-Sep-2023
• Revises: IEC 60238:1998 - Edison screw lampholders
• Effective Date: 05-Sep-2023
• Revises: IEC 60238:1998/AMD2:2002 - Amendment 2 - Edison screw lampholders
• Effective Date: 05-Sep-2023
• Revised: IEC 60238:2016 - Edison screw lampholders
• Effective Date: 05-Sep-2023

Overview

IEC 60238:2004 is an international standard published by the International Electrotechnical Commission (IEC) that governs the specifications for Edison screw lampholders. This standard specifically addresses lampholders with Edison thread sizes E14, E27, and E40 designed for connecting lamps and semi-luminaires to power supplies. It also covers switched lampholders intended for alternating current (a.c.) circuits with working voltages up to 250 V r.m.s. Additionally, IEC 60238:2004 includes provisions for smaller lampholders such as E5 and E10 threads used in series-connected lamps with lower voltage ratings (up to 25 V for E5, and up to 60 V for E10), applicable for indoor and outdoor usage depending on the type. The standard ensures design uniformity, compatibility, and safety across these commonly used lamp fittings worldwide.

Key Topics

• Scope and Application
  The standard applies to Edison screw lampholders for various lamp types and voltages, focusing on safe connection to electrical supply lines primarily for lighting applications.

• Design and Dimensions
  IEC 60238 defines critical measurements including thread profiles, shell thicknesses, and overall dimensions to ensure interchangeability and proper fit of screw lampholders across manufacturers.

• Electrical Safety Requirements
  The standard specifies protection against electric shock, creepage distances, clearances, insulation resistance, and electrical strength tests to guarantee safe operation.

• Mechanical Strength and Durability
  Testing procedures including mechanical strength, moisture resistance, and resistance to heat, fire, and rust ensure lampholders withstand operational stresses and environmental conditions.

• Marking and Identification
  Proper marking requirements enable clear identification of lampholders regarding size, ratings, and manufacturer details for regulatory compliance and user safety.

• Switched Lampholders
  Requirements for lampholders with integrated switches cover performance criteria under normal operation and specific test conditions, ensuring reliability in switched lighting applications.

• Annexes for Guidance
  Informative annexes provide additional guidance on requirements related to switches (IEC 61058-1) and special household appliance standards.

Applications

The IEC 60238:2004 standard is critical for manufacturers, designers, and users involved with:

• Lighting Fixture Design
  Ensuring compatibility of lampholders with standard Edison screw lamps used in residential, commercial, and industrial lighting.

• Lamp Manufacturing
  Guiding lamp producers in selecting appropriate lampholder sizes and ratings consistent with international safety standards.

• Safety Compliance
  Helping regulatory bodies and certification organizations evaluate the conformance of lampholders to guarantee safe electrical products in the market.

• Maintenance and Electrical Installation
  Assisting electricians and maintenance professionals in selecting and replacing lampholders that meet global standard requirements to maintain system integrity and electrical safety.

• Specialized Lighting Systems
  Providing specifications for low-voltage series-connected lamps found in decorative or specialty lighting applications indoors or outdoors.

Related Standards

• IEC 60598 Series
  Covers the general safety requirements for luminaires where Edison screw lampholders may be integrated.

• IEC 61058-1
  Addresses the requirements for switches in electrical appliances, relevant to switched lampholders with integrated switches.

• IEC 60364
  Pertains to electrical installations of buildings, complementing the safe installation of lampholder circuits.

• IEC 60529
  Defines degrees of protection by enclosures (IP Code), associated with the physical safety of lampholders in various environments.

• National and Regional Standards
  Local standards often adopt IEC 60238 guidelines for lampholders, with possible national deviations clearly identified as per IEC directives.

---

Adhering to IEC 60238:2004 globally standardizes Edison screw lampholders, promoting product interoperability, enhancing user safety, and supporting innovation in lamp and lighting technologies. This makes IEC 60238 an essential reference for anyone involved with electrical lamp fittings and lighting systems worldwide.

Standards Content (Sample)

IEC 60238
Edition 8.1 2008-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Edison screw lampholders
Douilles à vis Edison pour lampes
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IEC 60238
Edition 8.1 2008-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Edison screw lampholders
Douilles à vis Edison pour lampes

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CQ
CODE PRIX
ICS 29.140.10 ISBN 2-8318-9963-X
– 2 – 60238 © IEC:2004+A1:2008
CONTENTS
FOREWORD.4

1 General.6
2 Definitions.8
3 General requirement .11
4 General conditions for tests .11
5 Standard ratings .13
6 Classification.14
7 Marking.15
8 Dimensions.17
9 Protection against electric shock.19
10 Terminals.21
11 Provision for earthing.25
12 Construction.26
13 Switched lampholders .31
14 Moisture resistance, insulation resistance and electric strength .33
15 Mechanical strength.35
16 Screws, current-carrying parts and connections .39
17 Creepage distances and clearances.41
18 Normal operation .43
19 General resistance to heat .44
20 Resistance to heat, fire and tracking .47
21 Resistance to excessive residual stresses (season cracking) and to rusting .49

Annex A (normative)  Season cracking/corrosion test .51
Annex B (informative) Guidance for requirements in IEC 61058-1 applicable to switches
in lampholders (see 13.2).53
Annex C (informative) Guidance for special requirements in appliance standards –
Household and similar electrical appliances.55

Figure 1a – Nipple thread for lampholders. Basic profile and design profile for the nut
and for the screw .57
Figure 1b – Nipple thread for lampholders. Basic profile and design profile for the nut
and for the screw .58
Figure 2a – Gauges for metric ISO 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
Figure 6 – Torque apparatus .64
Figure 7 – Tumbling barrel .65

60238 © IEC:2004+A1:2008 – 3 –
Figure 8 – Impact-test apparatus .66
Figure 8a – Mounting support .66
Figure 9 – Pressure apparatus .67
Figure 10 – Ball-pressure test apparatus .67
Figure 11 – Test cap for the tests of 14.4 and 19.3 .68
Figure 12 – Bending apparatus.69
Figure 13 – Test cap A and test cap B for lampholders E14 .70
Figure 13 – Test cap A and test cap B for lampholders E14 (continued) .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 20.4 .76

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.23
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 a.c. (50/60 Hz) sinusoidal voltages Impulse
withstand category II .42
Table 13b – Minimum distances for a.c. (50/60 Hz) sinusoidal voltages Impulse
withstand category III .42
Table 14 – Minimum distances for non-sinusoidal pulse voltages .43
Table 15 – Heating cabinet temperatures .46
Table A.1 – pH adjustment .51

– 4 – 60238 © IEC:2004+A1:2008
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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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 consolidated version of IEC 60238 consists of the eighth edition (2004) [documents
34B/1151/FDIS and 34B/1170/RVD] and its amendment 1 (2008) [documents 34B/1381/FDIS
and 34B/1397/RVD].
The technical content is therefore identical to the base edition and its amendment and has
been prepared for user convenience.
It bears the edition number 8.1.
A vertical line in the margin shows where the base publication has been modified by
amendment 1.
In this edition the new requirements for creepage distances and clearances have been adopted
which are currently circulated by SC34D to amend the IEC 60598 family of luminaire standards.

60238 © IEC:2004+A1:2008 – 5 –
Additionally guidances for requirements in IEC 61058-1 applicable to switches in lampholders
(see Annex B) and for special requirements in appliance standards (see Annex C) have been
included.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of the base publication and its amendments will
remain unchanged until the maintenance result 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 – 60238 © IEC:2004+A1:2008
EDISON SCREW LAMPHOLDERS
1 General
1.1 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 a.c. 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 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,
e.g. 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.
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.
___________
*
Requirements for lampholders suitable for semi-luminaires are under consideration.

60238 © IEC:2004+A1:2008 – 7 –
1.2 Normative references
The following referenced documents are indispensable for the application of this document. 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, Environmental testing – Part 2: Tests – Test Ed: Free fall
IEC 60068-2-75:1997, Environmental testing – Part 2: Tests – Test Eh: Hammer tests
IEC 60112:1979, Method for determining the comparative and the proof tracking indices of solid
insulating materials under moist conditions
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 require-
ments, test methods and practical guidance
IEC 60399, Barrel thread for lampholders with shade holder ring
**)
IEC 60417-DB:2002 Graphical symbols for use on equipment
*)
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
Amendment 1 (1999)
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 60695-2-10:2000, Fire hazard testing – Part 2–10: Glowing/hot-wire based test methods –
Glow-wire apparatus and common test procedure
___________
)
* A consolidated edition 2.1 (2001) exists including edition 2.0 (1989) and its amendment 1(1999).

**) “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).
– 8 – 60238 © IEC:2004+A1:2008
IEC 60695-2-11:2000, Fire hazard testing – Part 2-11: Glowing/hot-wire based test methods –
Glow-wire flammability test method for end products
IEC 60695-11-5:2004, 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
2 Definitions
For the purpose of this International Standard, the following definitions apply. For clarification
of some definitions, see also figure 17.
2.1
cord-grip lampholder
a lampholder incorporating a method of retaining a flexible cord by which it may then be
suspended
2.2
threaded entry lampholder
a 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 (formerly called "nipple
lampholder")
2.3
backplate lampholder
a lampholder so designed as to be suitable for mounting by means of an associated or integral
back plate, directly onto a supporting surface or appropriate box
2.4
lampholder for building-in
a lampholder designed to be built into a luminaire, an additional enclosure or the like
2.4.1
unenclosed lampholder
a lampholder for building-in so designed that it requires additional means, for example an enclo-
sure, to meet the requirements of this standard with regard to protection against electric shock
2.4.2
enclosed lampholder
a 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
2.5
independent lampholder
a 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
2.6
terminal/contact assembly
a part or assembly of parts which provide(s) a means of connection between the termination of
a supply conductor and the contact making surfaces of the corresponding lamp cap

60238 © IEC:2004+A1:2008 – 9 –
2.7
outer shell
a cylindrical component protecting the user from contact with the lamp cap. It may or may not
be provided with an external screw thread for fixing a shade ring
2.7.1
snap-on outer shell
an outer shell for screwless assembly which does not contain the screw shell
NOTE 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.
2.8
screw shell
a cylindrical component having an internal screw thread of Edison form for the retention of the
corresponding lamp (cap)
In some constructions, the screw shell is permanently fixed to or integral with the outer shell.
2.9
insulating ring
a cylindrical intermediate piece of insulating material separating a metal screw shell and a
metal outer shell
2.10
shade ring
a 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
2.11
dome
a part of a cord-grip lampholder or threaded entry lampholder which shields the connecting
terminals
2.12
basic insulation
an insulation applied to live parts to provide basic protection against electric shock
NOTE Basic insulation does not necessarily include insulation used exclusively for functional purposes.
2.13
supplementary insulation
an 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
2.14
double insulation
an insulation comprising both basic insulation and supplementary insulation
2.15
reinforced insulation
a 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 The term "insulation system" does not imply that the insulation must be one homogeneous piece. It may
comprise several layers which cannot be tested singly as supplementary or basic insulation.

– 10 – 60238 © IEC:2004+A1:2008
2.16
live part
a conductive part which may cause an electric shock
2.17
type test
a 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
2.18
type test sample
a sample consisting of one or more similar specimens submitted by the manufacturer or
responsible vendor for the purpose of a type test
2.19
semi-luminaire
a unit similar to a self-ballasted lamp but designed to utilize a replaceable light source and/or
starting device
2.20
rated operating temperature
the highest temperature for which the holder is designed
2.21
rated minimum temperature
the lowest temperature for which the holder is designed (applicable only to lampholders
intended for use in refrigerators and food freezers)
2.22
angled lampholder
lampholder, the rear side of which (threaded entry and/or dome) is at an angled position to the
screw shell axis
2.23
lampholder with retention device
lampholder with a device intended to prevent the lamp from becoming loose in the holder
NOTE Lamps may, for example, become loose due to changes in temperature or to vibrations.
2.24
impulse withstand categories
a numeral defining a transient overvoltage condition
NOTE 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 categories 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.

60238 © IEC:2004+A1:2008 – 11 –
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.
2.25
primary circuit
a circuit which is directly connected to the AC mains supply. It includes, for example, the
means for connection to the AC mains supply, the primary windings of transformers, motors
and other loading devices
2.26
secondary circuit
a 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
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 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.
2.27
adapter
a component used for the electrical and mechanical connection of a lamp to a lampholder
NOTE 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 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.
4 General conditions for tests
4.1 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 include routine
tests and quality assurance.
****)
For further information see IEC 60061-4 (inclusion of guidance on conformity testing during manufacture is in
preparation).
___________
)
****
IEC 60061-4: Lamp caps and holders together with gauges for the control of interchangeability and safety –
Part 4: Guidelines and general information

– 12 – 60238 © IEC:2004+A1:2008
4.2 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.
4.3 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 1 to 12 (except for 9.1 and 10.2) and 14 to 17;
– three specimens clause 13 (switched-lampholder tests only);
– three specimens subclause 9.1 and clauses 18 and 19;
– two specimens clause 20 (of which one specimen for the test of 20.1 and the other for the
tests of 20.3 or 20.4);
– one specimen 20.5 and clause 21.
For testing lampholders with a retention device, the retention device shall be removed.
For testing lampholders with a retention device according to 12.14, three additional specimens
are required with the retention device kept in place.
NOTE For testing of screwless terminals according to 10.2, separate specimens are required in addition.
4.4 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.
4.5 For lampholders E40 with a rated current of 32 A, the tests shall be based on this rated
current.
4.6 Lampholders are deemed to comply with this standard if no specimen fails in the complete
series of tests specified in 4.3.
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 4.3,
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.
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.

60238 © IEC:2004+A1:2008 – 13 –
5 Standard ratings
5.1 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 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 These lampholders should also be used for such special cases as series-connected lamps, whereby 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.
5.2 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.
5.3 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.
5.4 The rated operating temperature for lampholders intended for use in high temperature
conditions (T marked holders) shall be not lower than 140 °C for E14 lampholders, not lower
than 170 °C for E27 lampholders 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.
– 14 – 60238 © IEC:2004+A1:2008
6 Classification
Lampholders are classified:
6.1 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 12.3). This does not apply to threaded entries and external parts, as 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 9.5).
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 14.4, the insulating resistance is measured
between the stripes. The surface is considered to be conductive if the resistance is less than
5 MΩ.
6.2 According to degree of protection against ingress of water:
– ordinary lampholders;
– drip-proof lampholders.
6.3 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.
6.4 According to type:
– switched-lampholders, provided with an integral switch to control the supply to the lamp;
– non-switched lampholders.
6.5 According to protection against electric shock:
– unenclosed lampholders;
– enclosed lampholders;
– independent lampholders.
6.6 According to resistance to heat:
– lampholders for rated operating temperatures up to the limits given in 5.4;
– lampholders for operating in high temperature conditions (T marked holders).

60238 © IEC:2004+A1:2008 – 15 –
7 Marking
7.1 Lampholders, other than lampholders E5 and E10, shall be marked with
– 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 1 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 2 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;
– the degree of protection against ingress of water for drip-proof lampholders (see 7.2);
– rated operating temperature "T", indicating the highest operating temperature, if applicable.
The marking of the rated operating temperature is not required for lampholders the exterior of
which 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,
distances for impulse withstand category III may be applicable. This information has to be
indicated in the manufacturer's catalogue or the like.
Lampholders complying with the electrical strength test for double or reinforced insulation and
having creepage distances and clearances equivalent to double or reinforced insulation offer
an adequate level of protection for the use in luminaries where they are accessible in normal
use. Such lampholders are addressed as lampholders for use in class II applications. This
information shall be indicated in the manufacturer’s catalogue or the like.
NOTE 3 Values for creepage distances and clearances as well as test voltages for the electrical strength test for
double or reinforced insulation are given in IEC 60598-1.
To achieve sufficient creepage distances and clearances to outer accessible surfaces
additional attachments could be used. In some cases, these dimensions might be achieved
only after mounting the lampholder in the luminaire. Relevant information should be provided in
the manufacturer’s catalogue or the like.
Lampholders E10 shall be marked with
– rated voltage, in volts;
– mark of origin;
– type reference;
– the degree of protection against ingress of water, if applicable.

– 16 – 60238 © IEC:2004+A1:2008
Lampholders E5 shall be marked with
– mark of origin;
– type reference.
Compliance is checked by inspection.
NOTE The type reference for lampholders E10 and E5 may be a catalogue number.
7.2 If symbols are used for current and voltage, A shall
...

NORME CEI
INTERNATIONALE
IEC
INTERNATIONAL
Huitième édition
STANDARD
Eighth edition
2004-10
Douilles à vis Edison pour lampes

Edison screw lampholders
Numéro de référence
Reference number
CEI/IEC 60238:2004
Numérotation des publications Publication numbering
Depuis le 1er janvier 1997, les publications de la CEI As from 1 January 1997 all IEC publications are
sont numérotées à partir de 60000. Ainsi, la CEI 34-1 issued with a designation in the 60000 series. For
devient la CEI 60034-1. example, IEC 34-1 is now referred to as IEC 60034-1.
Editions consolidées Consolidated editions
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CEI incorporant les amendements sont disponibles. Par publications. For example, edition numbers 1.0, 1.1
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respectivement la publication de base, la publication de the base publication incorporating amendment 1 and
base incorporant l’amendement 1, et la publication de the base publication incorporating amendments 1
base incorporant les amendements 1 et 2. and 2.
Informations supplémentaires Further information on IEC publications
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NORME CEI
INTERNATIONALE
IEC
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Huitième édition
STANDARD
Eighth edition
2004-10
Douilles à vis Edison pour lampes

Edison screw lampholders
 IEC 2004 Droits de reproduction réservés  Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any
utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including
électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
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CODE PRIX
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Pour prix, voir catalogue en vigueur
For price, see current catalogue

– 2 – 60238  CEI:2004
SOMMAIRE
AVANT-PROPOS .6

1 Généralités.10
2 Définitions.14
3 Prescriptions générales.20
4 Généralités sur les essais.22
5 Valeurs normales.24
6 Classification.26
7 Marques et indications .28
8 Dimensions.32
9 Protection contre les chocs électriques .36
10 Bornes.40
11 Dispositions en vue de la mise à la terre .48
12 Construction.50
13 Douilles à interrupteur.60
14 Résistance à l'humidité, résistance d'isolement et rigidité diélectrique .64
15 Résistance mécanique.68
16 Vis, parties transportant le courant et connexions.76
17 Lignes de fuite et distances dans l'air.80
18 Fonctionnement normal.84
19 Généralités sur la résistance à la chaleur.86
20 Résistance à la chaleur, au feu et aux courants de cheminement .92
21 Protection contre les contraintes résiduelles excessives (fissurations
intercristallines) et contre la rouille.96

Annexe A (normative)  Essai de fissuration intercristalline et de corrosion . 100
Annexe B (informative) Lignes directrices pour le choix des prescriptions de la
CEI 61058-1 applicable aux interrupteurs de douilles (voir 13.2) . 104
Annexe C (informative) Guide des prescriptions spécifiques des normes appareils −
Appareils électrodomestiques et similaires . 108

Figure 1a – Filetage des raccords pour douilles de lampes. Profil de base et profil
d'exécution pour l'écrou et pour la vis. 112
Figure 1b – Filetage des raccords pour douilles de lampes. Profil de base et profil
d'exécution pour l'écrou et pour la vis. 114
Figure 2a – Calibres pour filetage métrique ISO pour raccords de douilles . 116
Figure 2b – Calibres pour filetage ISO au pas du gaz pour raccords de douilles . 118
Figure 3 – Calibre pour les trous de fixation des douilles à embase . 120
Figure 4 – Appareil pour les essais de fonctionnement normal. 122
Figure 5 – Culots d'essai pour l’essai de l'article 18 . 124
Figure 6 – Appareil pour la résistance à la torsion . 126
Figure 7 – Tambour tournant . 128

60238  IEC:2004 – 3 –
CONTENTS
FOREWORD.7

1 General.11
2 Definitions.15
3 General requirement.21
4 General conditions for tests .23
5 Standard ratings.25
6 Classification.27
7 Marking.29
8 Dimensions.33
9 Protection against electric shock.37
10 Terminals.41
11 Provision for earthing.49
12 Construction.51
13 Switched lampholders.61
14 Moisture resistance, insulation resistance and electric strength .65
15 Mechanical strength.69
16 Screws, current-carrying parts and connections .77
17 Creepage distances and clearances.81
18 Normal operation.85
19 General resistance to heat .87
20 Resistance to heat, fire and tracking .93
21 Resistance to excessive residual stresses (season cracking) and to rusting .97

Annex A (normative)  Season cracking/corrosion test . 101
Annex B (informative) Guidance for requirements in IEC 61058-1 applicable to switches
in lampholders (see 13.2). 105
Annex C (informative) Guidance for special requirements in appliance standards –
Household and similar electrical appliances. 109

Figure 1a – Nipple thread for lampholders. Basic profile and design profile for the nut
and for the screw . 113
Figure 1b – Nipple thread for lampholders. Basic profile and design profile for the nut
and for the screw . 115
Figure 2a – Gauges for metric ISO thread for nipples . 117
Figure 2b – Gauges for ISO standard pipe thread for nipples . 119
Figure 3 – Gauge for holes for backplate lampholder screws . 121
Figure 4 – Normal operation test apparatus . 123
Figure 5 – Test caps for the test of clause 18 . 125
Figure 6 – Torque apparatus . 127
Figure 7 – Tumbling barrel . 129

– 4 – 60238  CEI:2004
Figure 8 – Appareil pour l'essai de choc . 130
Figure 8a – Support de montage . 130
Figure 9 – Appareil pour la résistance à la compression . 132
Figure 10 – Appareil pour l'essai à la bille. 132
Figure 11 – Culot d'essai pour les essais de 14.4 et 19.3. 134
Figure 12 – Appareil pour la résistance à la flexion . 136
Figure 13 – Culot d'essai A et culot d'essai B pour les douilles E14 . 138
Figure 13 – Culot d'essai A et culot d'essai B pour les douilles E14 (suite). 140
Figure 14 – Culot d'essai pour les douilles E27. 142
Figure 15 – Culot d'essai pour les douilles E40. 144
Figure 16 – Doigt d'épreuve normalisé (d'après la CEI 60529) . 146
Figure 17 – Clarification de quelques définitions . 148
Figure 18 – Préparation des spécimens pour l'essai au brûleur-aiguille de 20.4 . 150

Tableau 1 – Epaisseurs des chemises filetées et des contacts .34
Tableau 2 – Longueurs effectives minimales du filetage .34
Tableau 3 – Dimensions des entrées taraudées et des vis d'arrêt .36
Tableau 4 – Dimensions minimales des bornes à trous.44
Tableau 5 – Dimensions minimales des bornes à serrage.44
Tableau 6 – Valeurs de fraction et de torsion.56
Tableau 7 – Couple d’insertion .60
Tableau 8 – Couples de dévissage minimal et maximal .60
Tableau 9 – Dimensions des culots d'essai.68
Tableau 10 – Hauteurs de chute.72
Tableau 11 – Valeurs de déformation maximales.74
Tableau 12 – Valeurs de torsion .78
Table 13a – Distances minimales pour les tensions sinusoïdales (50/60 Hz)
Catégorie de résistance aux chocs II .82
Table 13b – Distances minimales pour les tensions sinusoïdales (50/60 Hz)
Catégorie de résistance aux chocs III .82
Tableau 14 – Distances minimales pour les impulsions de tension non sinusoïdales .84
Tableau 15 – Températures dans l'étuve .90
Tableau A.1 – Réglage du pH. 100

60238  IEC:2004 – 5 –
Figure 8 – Impact-test apparatus . 131
Figure 8a – Mounting support . 131
Figure 9 – Pressure apparatus . 133
Figure 10 – Ball-pressure test apparatus . 133
Figure 11 – Test cap for the tests of 14.4 and 19.3 . 135
Figure 12 – Bending apparatus. 137
Figure 13 – Test cap A and test cap B for lampholders E14 . 139
Figure 13 – Test cap A and test cap B for lampholders E14 (continued) . 141
Figure 14 – Test cap for lampholders E27 . 143
Figure 15 – Test cap for lampholders E40 . 145
Figure 16 – Standard test finger (according to IEC 60529) . 147
Figure 17 – Clarification of some definitions . 149
Figure 18 – Preparation of specimens for the needle-flame test of 20.4 . 151

Table 1 – Thickness of screw shells and contacts.35
Table 2 – Minimum effective screw lengths.35
Table 3 – Dimensions of threaded entries and set screws.37
Table 4 – Minimum dimensions of pillar-type terminals .45
Table 5 – Minimum dimensions of screw-type terminals.45
Table 6 – Pull and torque values .57
Table 7 – Insertion torque .61
Table 8 – Minimum and maximum removal torques .61
Table 9 – Test cap dimensions.69
Table 10 – Heights of fall .73
Table 11 – Maximum deformation values.75
Table 12 – Torque values.79
Table 13a – Minimum distances for a.c. (50/60 Hz) sinusoidal voltages Impulse
withstand category II .83
Table 13b – Minimum distances for a.c. (50/60 Hz) sinusoidal voltages Impulse
withstand category III .83
Table 14 – Minimum distances for non-sinusoidal pulse voltages .85
Table 15 – Heating cabinet temperatures .91
Table A.1 – pH adjustment . 101

– 6 – 60238  CEI:2004
COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE
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DOUILLES À VIS EDISON POUR LAMPES

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référencées est obligatoire pour une application correcte de la présente publication.
9) L’attention est attirée sur le fait que certains des éléments de la présente Publication de la CEI peuvent faire
l’objet de droits de propriété intellectuelle ou de droits analogues. La CEI ne saurait être tenue pour
responsable de ne pas avoir identifié de tels droits de propriété et de ne pas avoir signalé leur existence.
La Norme internationale CEI 60238 a été établie par le sous-comité 34B: Culots et douilles, du
comité d'études 34 de la CEI: Lampes et équipements associés.
Cette huitième édition annule et remplace la septième édition parue en 1998 et ses
amendements 1 (1999) et 2 (2002). Cette huitième édition constitue une révision technique.
Dans cette édition, les nouvelles exigences concernant les lignes de fuite et distances dans
l’air ont été adoptées, qui sont actuellement en cours d’examen par le SC34D pour modifier les
normes luminaires de la famille CEI 60598.
En complément, des lignes directrices ont été introduites pour, d’une part, le choix des
exigences de la CEI 61058-1 applicable aux interrupteurs de douilles (voir l’Annexe B) et,
d’autre part, pour les exigences spécifiques des normes appareils (voir l’Annexe C).

60238  IEC:2004 – 7 –
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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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 eighth edition cancels and replaces the seventh edition published in 1998 and its
amendments 1 (1999) and 2 (2002). This eighth edition constitutes a technical revision.
In this edition the new requirements for creepage distances and clearances have been adopted
which are currently circulated by SC34D to amend the IEC 60598 family of luminaire standards.
Additionally guidances for requirements in IEC 61058-1 applicable to switches in lampholders
(see Annex B) and for special requirements in appliance standards (see Annex C) have been
included.
– 8 – 60238  CEI:2004
Le texte de cette norme est issu des documents suivants:
FDIS Rapport de vote
34B/1151/FDIS 34B/1170/RVD
Le rapport de vote indiqué dans le tableau ci-dessus donne toute information sur le vote ayant
abouti à l'approbation de cette norme.
Cette publication a été rédigée selon les Directives ISO/CEI, Partie 2.
Le comité a décidé que le contenu de cette publication ne sera pas modifié avant la date de
maintenance indiquée sur le site web de la CEI sous "http://webstore.iec.ch" dans les données
relatives à la publication recherchée. A cette date, la publication sera
• reconduite,
• supprimée,
• remplacée par une édition révisée, ou
• amendée.
60238  IEC:2004 – 9 –
The text of this standard is based on the following documents:
FDIS Report on voting
34B/1151/FDIS 34B/1170/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.
The committee has decided that the contents of this publication will remain unchanged until the
maintenance result 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.
– 10 – 60238  CEI:2004
DOUILLES À VIS EDISON POUR LAMPES

1 Généralités
1.1 Domaine d'application
La présente Norme internationale 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 service ne dépasse pas 250 V (valeur efficace).
La présente norme est également applicable aux douilles à vis Edison E5 destinées à être
raccordées au réseau d'alimentation de lampes montées en série et dont la tension de
fonctionnement ne dépasse pas 25 V, pour utilisation à l'intérieur, ainsi qu'aux douilles à vis
Edison E10 destinées au raccordement au réseau d'alimentation de lampes montées en série
et dont la tension de fonctionnement ne dépasse pas 60 V, pour utilisation à l'intérieur ou à
l'extérieur. Elle s'applique également aux douilles E10 à incorporer, pour le raccordement de
lampes individuelles à l'alimentation. Ces douilles ne sont pas destinées à la vente au détail.
Pour autant que la présente norme soit applicable, elle couvre également d'autres douilles que
celles à vis Edison destinées au raccordement à l'alimentation de lampes branchées en série.
NOTE Ce type de douille est employé par exemple dans les guirlandes lumineuses pour arbres de Noël.
Pour autant que l’on puisse raisonnablement l’appliquer, cette norme couvre également les
adaptateurs.
La présente norme couvre aussi les douilles totalement ou partiellement intégrées au luminaire
ou prévues pour être montées dans les appareils. Elle ne couvre que les prescriptions relatives
à la douille. Pour toutes les autres prescriptions telles que la protection contre les chocs
électriques dans la zone des bornes ou du culot de la lampe, les prescriptions de la norme de
l’appareil concerné doivent être respectées et les essais réalisés après incorporation dans
l’appareil approprié, lorsque cet appareil est essayé selon sa propre norme. De telles douilles
ainsi que les douilles pourvues d’un écran extérieur enclenchable, destinées aux fabricants de
luminaires exclusivement, ne sont pas destinées à la vente au détail.
La présente norme s'applique aux douilles utilisées à l'intérieur ou à l'extérieur de bâtiments et
destinées aux installations d'éclairage domestique ou industriel. Elle s'applique également aux
douilles-bougies. Des constructions spéciales peuvent être exigées dans des endroits où
règnent des conditions particulières, comme dans le cas de l'éclairage public, à bord des
navires, dans les véhicules et dans les locaux à atmosphère dangereuse présentant, par
exemple, des risques d'explosion.
NOTE 1 La présente norme n'est pas applicable aux douilles E26d pour lampes à trois puissances.
NOTE 2 La présente norme est basée sur les données suivantes, relatives aux lampes pour éclairage général
– les culots E14 sont utilisés pour des lampes absorbant un courant ne dépassant pas 2 A;
– les culots E27 sont utilisés pour des lampes absorbant un courant ne dépassant pas 4 A;
– les culots E40 sont utilisés pour des lampes absorbant un courant ne dépassant pas 16 A.
NOTE 3 Si la tension nominale d'alimentation ne dépasse pas 130 V, la valeur maximale du courant pour les
culots E40 est de 32 A (voir 4.5 et 5.3).
NOTE 4 Quand les douilles sont utilisées dans des luminaires, leurs températures maximales de fonctionnement
sont spécifiées dans la CEI 60598.
___________
*
Les prescriptions applicables aux douilles pour semi-luminaires sont à l'étude.

60238  IEC:2004 – 11 –
EDISON SCREW LAMPHOLDERS
1 General
1.1 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 a.c. 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 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,
e.g. 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.
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.
___________
*
Requirements for lampholders suitable for semi-luminaires are under consideration.

– 12 – 60238  CEI:2004
1.2 Références normatives
Les documents de référence suivants sont indispensables pour l'application du présent document.
Pour les références datées, seule l'édition citée s'applique. Pour les références non datées,
la dernière édition du document de référence s'applique (y compris les éventuels amendements).
NOTE En ce qui concerne la CEI 60598-1, les références citées dans le présent document sont susceptibles de
changer.
CEI 60061 (toutes les parties), Culots de lampes et douilles ainsi que calibres pour le contrôle
de l'interchangeabilité et de la sécurité
CEI 60061-1: Culots de lampes et douilles ainsi que calibres pour le contrôle de
l'interchangeabilité et de la sécurité – Partie 1: Culots de lampes
CEI 60061-2: Culots de lampes et douilles ainsi que calibres pour le contrôle de
l'interchangeabilité et de la sécurité – Partie 2: Douilles
CEI 60061-3: Culots de lampes et douilles ainsi que calibres pour le contrôle de
l'interchangeabilité et de la sécurité – Partie 3: Calibres
CEI 60068-2-20:1979, Essais d'environnement – Deuxième partie: Essais. Essai T: Soudure
CEI 60068-2-32:1975, Essais d'environnement – Deuxième partie: Essais. Essai Ed: Chute libre
CEI 60068-2-75:1997, Essais d'environnement – Partie 2-75: Essais. Essai Eh: Essais aux
marteaux
CEI 60112:1979, Méthode pour déterminer les indices de résistance et de tenue au
cheminement des matériaux isolants solides dans des conditions humides
CEI 60227 (toutes les parties) Conducteurs et câbles isolés au polychlorure de vinyle, de
tension nominale au plus égale à 450/750 V
CEI 60245 (toutes les parties) Conducteurs et câbles isolés au caoutchouc – Tension assignée
au plus égale à 450/750 V
CEI 60335-1:2001, Appareils électrodomestiques et analogues – Sécurité – Partie 1:
Prescriptions générales
CEI 60352-1:1997, Connexions sans soudure – Partie 1: Connexions enroulées– Règles
générales, méthodes d'essai et guide pratique
CEI 60399, Filetage à filets ronds pour douilles avec bague support d'abat-jour
)
CEI 60417-DB:2002** , Symboles graphiques utilisables sur le matériel
*)
CEI 60529:1989, Degrés de protection procurés par les enveloppes (Code IP)
Amendement 1 (1999)
CEI 60598 (toutes les parties et sections), Luminaires
CEI 60598-1, Luminaires – Partie 1: Prescriptions générales et essais
CEI 60664-1:1992, Coordination de l'isolement des matériels dans les systèmes (réseaux) à
***)
basse tension – Partie 1: Principes, prescriptions et essais
Amendement 1 (2000)
Amendement 2 (2002)
___________
*)
Il existe une édition consolidée 2.1 (2001) comprenant l'édition 2.0 (1989) et son amendment 1 (1999).
**)
“DB” se réfère à la base de données “online” de la CEI.
***)
Il existe une édition consolidée 1.2 (2002) comprenant l'édition 1.0 (1992), l’amendement 1 (2000) et
l’amendment 2 (2002).
60238  IEC:2004 – 13 –
1.2 Normative references
The following referenced documents are indispensable for the application of this document. 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, Environmental testing – Part 2: Tests – Test Ed: Free fall
IEC 60068-2-75:1997, Environmental testing – Part 2: Tests – Test Eh: Hammer tests
IEC 60112:1979, Method for determining the comparative and the proof tracking indices of solid
insulating materials under moist conditions
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 require-
ments, test methods and practical guidance
IEC 60399, Barrel thread for lampholders with shade holder ring
**)
IEC 60417-DB:2002 Graphical symbols for use on equipment
*)
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
Amendment 1 (1999)
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)
___________
)
* A consolidated edition 2.1 (2001) exists including edition 2.0 (1989) and its amendment 1(1999).

**) “DB” refers to the IEC on-line database.
***)
A consolidated edition 1.2 (2002) exists including edition 1.0 (1992) and its amendment 1
...

IEC 60238 ®
Edition 8.2 2011-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Edison screw lampholders
Douilles à vis Edison pour lampes

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IEC 60238 ®
Edition 8.2 2011-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Edison screw lampholders
Douilles à vis Edison pour lampes

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX CR
ICS ICS 29.140.10 ISBN 978-2-88912-513-5

– 2 – 60238  IEC:2004+A1:2008+A2:2011
CONTENTS
FOREWORD . 4

1 General . 6
2 Definitions . 8
3 General requirement . 11
4 General conditions for tests . 12
5 Standard ratings . 13
6 Classification . 14
7 Marking . 15
8 Dimensions . 17
9 Protection against electric shock . 19
10 Terminals . 21
11 Provision for earthing . 25
12 Construction . 26
13 Switched lampholders . 31
14 Moisture resistance, insulation resistance and electric strength . 32
15 Mechanical strength . 34
16 Screws, current-carrying parts and connections . 38
17 Creepage distances and clearances . 40
18 Normal operation . 43
19 General resistance to heat . 44
20 Resistance to heat, fire and tracking . 46
21 Resistance to excessive residual stresses (season cracking) and to rusting . 49

Annex A (normative)  Season cracking/corrosion test . 50
Annex B (informative) Guidance for requirements in IEC 61058-1 applicable to switches
in lampholders (see 13.2) . 52
Annex C (informative) Guidance for special requirements in appliance standards –
Household and similar electrical appliances . 54

Figure 1a – Nipple thread for lampholders. Basic profile and design profile for the nut
and for the screw . 56
Figure 1b – Nipple thread for lampholders. Basic profile and design profile for the nut
and for the screw . 57
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
Figure 6 – Torque apparatus . 64
Figure 7 – Tumbling barrel . 65
Figure 8 – Impact-test apparatus . 66

60238  IEC:2004+A1:2008+A2:2011 – 3 –
Figure 8a – Mounting support . 66
Figure 9 – Pressure apparatus . 67
Figure 10 – Ball-pressure test apparatus . 67
Figure 11 – Test cap for the tests of 14.4 and 19.3 . 68
Figure 12 – Bending apparatus . 69
Figure 13 – Test cap A and test cap B for lampholders E14 . 70
Figure 13 – Test cap A and test cap B for lampholders E14 (continued) . 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)The drawings are intended
only to show typical parts of a lampholder and should not limit the design. . 74
Figure 17 – Clarification of some definitions . 75
Figure 18 – Preparation of specimens for the needle-flame test of 20.4 . 76

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 . 23
Table 6 – Pull and torque values . 29
Table 7 – Insertion torque . 30
Table 8 – Minimum and maximum removal torques . 31
Table 9 – Test cap dimensions . 35
Table 10 – Heights of fall . 36
Table 11 – Maximum deformation values . 37
Table 12 – Torque values . 39
Table 13a – Minimum distances for a.c. (50/60 Hz) sinusoidal voltages Impulse
withstand category II . 41
Table 13b – Minimum distances for a.c. (50/60 Hz) sinusoidal voltages Impulse
withstand category III . 42
Table 14 – Minimum distances for non-sinusoidal pulse voltages . 42
Table 15 – Heating cabinet temperatures . 45
Table A.1 – pH adjustment . 50

– 4 – 60238  IEC:2004+A1:2008+A2:2011
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 consolidated version of IEC 60238 consists of the eighth edition (2004) [documents
34B/1151/FDIS and 34B/1170/RVD], its amendment 1 (2008) [documents 34B/1381/FDIS and
34B/1397/RVD] and its amendment 2 (2011) [documents 34B/1577/FDIS and 34B/1593/RVD].
The technical content is therefore identical to the base edition and its amendments and has
been prepared for user convenience.
It bears the edition number 8.2.
A vertical line in the margin shows where the base publication has been modified by
amendments 1 and 2.
In this edition the new requirements for creepage distances and clearances have been adopted
which are currently circulated by SC34D to amend the IEC 60598 family of luminaire standards.

60238  IEC:2004+A1:2008+A2:2011 – 5 –
Additionally guidances for requirements in IEC 61058-1 applicable to switches in lampholders
(see Annex B) and for special requirements in appliance standards (see Annex C) have been
included.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
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.
– 6 – 60238  IEC:2004+A1:2008+A2:2011
EDISON SCREW LAMPHOLDERS
1 General
1.1 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 a.c. 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 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,
e.g. 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.
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.
___________
*
Requirements for lampholders suitable for semi-luminaires are under consideration.

60238  IEC:2004+A1:2008+A2:2011 – 7 –
1.2 Normative references
The following referenced documents are indispensable for the application of this document. 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, Environmental testing – Part 2: Tests – Test Ed: Free fall
IEC 60068-2-75:1997, Environmental testing – Part 2: Tests – Test Eh: Hammer tests
IEC 60112:1979, Method for determining the comparative and the proof tracking indices of solid
insulating materials under moist conditions
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 require-
ments, test methods and practical guidance
IEC 60399, Barrel thread for lampholders with shade holder ring
**)
IEC 60417-DB:2002 Graphical symbols for use on equipment
*)
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
Amendment 1 (1999)
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 60695-2-10:2000, Fire hazard testing – Part 2–10: Glowing/hot-wire based test methods –
Glow-wire apparatus and common test procedure
___________
)
* A consolidated edition 2.1 (2001) exists including edition 2.0 (1989) and its amendment 1(1999).

**) “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).
– 8 – 60238  IEC:2004+A1:2008+A2:2011
IEC 60695-2-11:2000, Fire hazard testing – Part 2-11: Glowing/hot-wire based test methods –
Glow-wire flammability test method for end products
IEC 60695-11-5:2004, 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
2 Definitions
For the purpose of this International Standard, the following definitions apply. For clarification
of some definitions, see also figure 17.
2.1
cord-grip lampholder
a lampholder incorporating a method of retaining a flexible cord by which it may then be
suspended
2.2
threaded entry lampholder
a 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 (formerly called "nipple
lampholder")
2.3
backplate lampholder
a lampholder so designed as to be suitable for mounting by means of an associated or integral
back plate, directly onto a supporting surface or appropriate box
2.4
lampholder for building-in
a lampholder designed to be built into a luminaire, an additional enclosure or the like
2.4.1
unenclosed lampholder
a lampholder for building-in so designed that it requires additional means, for example an enclo-
sure, to meet the requirements of this standard with regard to protection against electric shock
2.4.2
enclosed lampholder
a 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
2.5
independent lampholder
a 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
2.6
terminal/contact assembly
a part or assembly of parts which provide(s) a means of connection between the termination of
a supply conductor and the contact making surfaces of the corresponding lamp cap

60238  IEC:2004+A1:2008+A2:2011 – 9 –
2.7
outer shell
a cylindrical component protecting the user from contact with the lamp cap. It may or may not
be provided with an external screw thread for fixing a shade ring
2.7.1
snap-on outer shell
an outer shell for screwless assembly which does not contain the screw shell
NOTE 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.
2.8
screw shell
a cylindrical component having an internal screw thread of Edison form for the retention of the
corresponding lamp (cap)
In some constructions, the screw shell is permanently fixed to or integral with the outer shell.
2.9
insulating ring
a cylindrical intermediate piece of insulating material separating a metal screw shell and a
metal outer shell
2.10
shade ring
a 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
2.11
dome
a part of a cord-grip lampholder or threaded entry lampholder which shields the connecting
terminals
2.12
basic insulation
an insulation applied to live parts to provide basic protection against electric shock
NOTE Basic insulation does not necessarily include insulation used exclusively for functional purposes.
2.13
supplementary insulation
an 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
2.14
double insulation
an insulation comprising both basic insulation and supplementary insulation
2.15
reinforced insulation
a 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 The term "insulation system" does not imply that the insulation must be one homogeneous piece. It may
comprise several layers which cannot be tested singly as supplementary or basic insulation.

– 10 – 60238  IEC:2004+A1:2008+A2:2011
2.16
live part
a conductive part which may cause an electric shock
2.17
type test
a 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
2.18
type test sample
a sample consisting of one or more similar specimens submitted by the manufacturer or
responsible vendor for the purpose of a type test
2.19
semi-luminaire
a unit similar to a self-ballasted lamp but designed to utilize a replaceable light source and/or
starting device
2.20
rated operating temperature
the highest temperature for which the holder is designed
2.21
rated minimum temperature
the lowest temperature for which the holder is designed (applicable only to lampholders
intended for use in refrigerators and food freezers)
2.22
angled lampholder
lampholder, the rear side of which (threaded entry and/or dome) is at an angled position to the
screw shell axis
2.23
lampholder with retention device
lampholder with a device intended to prevent the lamp from becoming loose in the holder
NOTE Lamps may, for example, become loose due to changes in temperature or to vibrations.
2.24
impulse withstand categories
a numeral defining a transient overvoltage condition
NOTE 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 categories 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.

60238  IEC:2004+A1:2008+A2:2011 – 11 –
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.
2.25
primary circuit
a circuit which is directly connected to the AC mains supply. It includes, for example, the
means for connection to the AC mains supply, the primary windings of transformers, motors
and other loading devices
2.26
secondary circuit
a 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
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 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.
2.27
adapter
a component used for the electrical and mechanical connection of a lamp to a lampholder
NOTE 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.
2.28
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
2.29
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 In some cases, the dimensions might be achieved only after mounting into the luminaire.
3 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.

– 12 – 60238  IEC:2004+A1:2008+A2:2011
4 General conditions for tests
4.1 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 include routine
tests and quality assurance.
****)
For further information see IEC 60061-4 (inclusion of guidance on conformity testing during manufacture is in
preparation).
4.2 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.
4.3 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 1 to 12 (except for 9.1 and 10.2) and 14 to 17;
– three specimens clause 13 (switched-lampholder tests only);
– three specimens subclause 9.1 and clauses 18 and 19;
– two specimens clause 20 (of which one specimen for the test of 20.1 and the other for the
tests of 20.3 or 20.4);
– one specimen 20.5 and clause 21.
For testing lampholders with a retention device, the retention device shall be removed.
For testing lampholders with a retention device according to 12.14, three additional specimens
are required with the retention device kept in place.
NOTE For testing of screwless terminals according to 10.2, separate specimens are required in addition.
4.4 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.
4.5 For lampholders E40 with a rated current of 32 A, the tests shall be based on this rated
current.
4.6 Lampholders are deemed to comply with this standard if no specimen fails in the complete
series of tests specified in 4.3.
___________
)
****
IEC 60061-4: Lamp caps and holders together with gauges for the control of interchangeability and safety –
Part 4: Guidelines and general information

60238  IEC:2004+A1:2008+A2:2011 – 13 –
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 4.3,
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.
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.
5 Standard ratings
5.1 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 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 These lampholders should also be used for such special cases as series-connected lamps, whereby 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.
5.2 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.
5.3 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.

– 14 – 60238  IEC:2004+A1:2008+A2:2011
5.4 The rated operating temperature for lampholders intended for use in high temperature
conditions (T marked holders) shall be not lower than 140 °C for E14 lampholders, not lower
than 170 °C for E27 lampholders 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.
6 Classification
Lampholders are classified:
6.1 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 12.3). This does not apply to threaded entries and external parts, as 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 9.5).
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 14.4, the insulating resistance is measured
between the stripes. The surface is considered to be conductive if the resistance is less than
5 MΩ.
6.2 According to degree of protection against ingress of water:
– ordinary lampholders;
– drip-proof lampholders.
6.3 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.
6.4 According to type:
– switched-lampholders, provided with an integral switch to control the supply to the lamp;
– non-switched lampholders.
60238  IEC:2004+A1:2008+A2:2011 – 15 –
6.5 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 may be
regarded as equivalent to a reinforced insulated lampholder.
6.6 According to resistance to heat:
– lampholders for rated operating temperatures up to the limits given in 5.4;
– lampholders for operating in high temperature conditions (T marked holders).
7 Marking
7.1 Lampholders, other than lampholders E5 and E10, shall be marked with
– 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 1 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 2 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;
NOTE 3 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, may 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 7.2);
– rated operating temperature "T", indicating the highest operating temperature, if applicable.
The marking of the rated operating temperature is not required for lampholders the exterior of
which is made wholly of ceramic materi
...