General procedure for verifying the effectiveness of the protective measures of electrical equipment after repair

This document specifies requirements for setting a uniform procedure to verify the effectiveness of the protective measures for current-using equipment or appliances after they have been repaired. This procedure is applicable to current-using equipment or appliances with a rated voltage above 25 V AC and 60 V DC up to 1 000 V AC and 1 500 V DC, and currents up to 63 A, connected to final circuits. They may be either pluggable equipment type A connected or permanently connected. This document is not intended to replace test covered by safety standards nor product standards, for example type tests, routine tests and acceptance tests. This document assumes that the current-using equipment or appliances under consideration complies with its related product standard, has been introduced on the market, has been in use, has failed, and has then been repaired. It intends to verify that operations for repairs have not jeopardized basic protective measures, for example to verify the continuity of the protective conductor, the withstand capability of the insulation or to verify that no metallic part is loose or is inadvertently inserted in the device. This document does not apply to: - recurrent tests defined in EN 50699; - devices and equipment that are part of the fixed electrical installations. For these, tests for verification after repair are covered by HD 60364 6; - audio/video, information and communication technology equipment; - uninterruptible Power Supply (UPS); - charging stations for electro-mobility; - power supplies; - programmable Logic Controllers (PLC); - power Drives; - devices for EX-zones or for mining applications in general; - products already covered by standards addressing similar topics such as: - medical equipment covered by EN 60601 1. For these devices, tests for verification after repair are covered by EN 62353; - arc welding equipment covered by EN IEC 60974 1. For these devices, tests for verification after repair are covered by EN 60974 4. - machinery covered by EN 60204-1. For these devices, EN 60204-1 applies.

Allgemeines Verfahren zur Überprüfung der Wirksamkeit der Schutzmaßnahmen von Elektrogeräten nach der Reparatur

Procédure générale visant à vérifier l'efficacité des mesures de protection des équipements électriques après réparation

Le présent document spécifie les exigences relatives à la définition d'une procédure uniforme visant à vérifier l'efficacité des mesures de protection pour les matériels ou appareils d'utilisation après leur réparation. Cette procédure s'applique aux matériels ou appareils d'utilisation avec une tension assignée supérieure à 25 V en courant alternatif et 60 V en courant continu jusqu'à 1 000 V en courant alternatif et 1 500 V en courant continu et des courants jusqu'à 63 A, raccordés à des circuits terminaux. Il peut s'agir d'équipements enfichables de type A ou d'équipements reliés en permanence. Le présent document ne vise pas à remplacer les essais couverts par les normes de sécurité ou les normes de produit, par exemple les essais de type, les essais individuels de série et les essais d'acceptation. Le présent document retient l'hypothèse que les matériels ou appareils d'utilisation à l'étude sont conformes à la norme de produit associée, qu'ils ont été mis sur le marché, qu'ils ont été utilisés, qu'ils ont subi une panne et qu'ils ont ensuite été réparés. Il vise à vérifier que les actions de réparation n'ont pas compromis les mesures de protection de base, pour contrôler par exemple la continuité du conducteur de protection, la capacité de tenue de l'isolement, ou pour contrôler qu'aucune pièce métallique ne s'est desserrée ou n'a été insérée dans l'appareil par inadvertance. Ce document ne s'applique pas aux: — essais récurrents définis dans l'EN 50699; — dispositifs et équipements qui font partie des installations électriques fixes. Pour ceux-ci, les essais concernant la vérification après réparation sont couverts par la norme HD 60364 6; — équipements des technologies de l'audio/vidéo, de l'information et de la communication; — alimentations sans interruptions (ASI); — bornes de charge pour l'électromobilité; — alimentations; — automates programmables (AP); — entraînements de puissance; — dispositifs pour les zones explosives (EX) ou pour les applications minières en général; — produits déjà couverts par des normes traitant de sujets similaires, tels que: — les appareils médicaux couverts par l'EN 60601 1. Pour ces dispositifs, les essais concernant la vérification après réparation sont couverts par l'EN 62353; — le matériel de soudage à l'arc couvert par l'EN IEC 60974 1. Pour ces dispositifs, les essais concernant la vérification après réparation sont couverts par l'EN 60974 4; — les machines couvertes par l'EN 60204-1. Pour ces dispositifs, l'EN 60204-1 s'applique.

Splošni postopek preverjanja učinkovitosti zaščitnih ukrepov za električno opremo po popravilu

General Information

Status
Published
Publication Date
05-Mar-2020
Current Stage
6060 - Document made available
Due Date
06-Mar-2020
Completion Date
06-Mar-2020

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SLOVENSKI STANDARD
SIST EN 50678:2020
01-julij-2020
Splošni postopek preverjanja učinkovitosti zaščitnih ukrepov za električno
opremo po popravilu

General procedure for verifying the effectiveness of the protective measures of electrical

equipment after repair
Allgemeines Verfahren zur Überprüfung der Wirksamkeitder Schutzmaßnahmen von
Elektrogeräten nach der Reparatur
Procédure générale visant à vérifier l'efficacité des mesures de protection des
équipements électriques après réparation
Ta slovenski standard je istoveten z: EN 50678:2020
ICS:
17.220.20 Merjenje električnih in Measurement of electrical
magnetnih veličin and magnetic quantities
SIST EN 50678:2020 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 50678:2020
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SIST EN 50678:2020
EUROPEAN STANDARD EN 50678
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2020
ICS 17.220.20
English Version
General procedure for verifying the effectiveness of the
protective measures of electrical equipment after repair

Procédure générale visant à vérifier l'efficacité des mesures Allgemeines Verfahren zur Überprüfung der Wirksamkeit

de protection des équipements électriques après réparation der Schutzmaßnahmen von Elektrogeräten nach der

Reparatur

This European Standard was approved by CENELEC on 2019-12-16. CENELEC members are bound to comply with the CEN/CENELEC

Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC

Management Centre or to any CENELEC member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation

under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the

same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,

Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the

Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,

Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2020 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN 50678:2020 E
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SIST EN 50678:2020
EN 50678:2020 (E)
Contents Page

European foreword .................................................................................................................................. 3

Introduction .............................................................................................................................................. 3

1 Scope .............................................................................................................................................. 5

2 Normative references ...................................................................................................................... 6

3 Terms and definitions ...................................................................................................................... 6

4 Requirements .................................................................................................................................. 9

5 Tests ................................................................................................................................................ 9

5.1 General .................................................................................................................................. 9

5.1.1 General test conditions .................................................................................................. 9

5.1.2 Visual inspection ......................................................................................................... 10

5.1.3 Test of the protective measures against electric hazards ........................................... 10

5.1.4 Confirmation of the compliance of additional protective measures ............................. 10

5.1.5 Documentation and evaluation of test ......................................................................... 10

5.2 Visual inspection .................................................................................................................. 11

5.3 Measurement of protective bonding resistance ................................................................... 11

5.4 Measurement of the insulation resistance ........................................................................... 14

5.5 Measurement of protective conductor current ..................................................................... 21

5.6 Measurement of the touch-current ...................................................................................... 27

5.7 Confirmation of the compliance of the specifications for the protective measure

SELV/PELV ......................................................................................................................... 31

5.8 Measurement of the leakage current produced by a floating input with a rated input

voltage above 50 V AC or 120 V DC ................................................................................... 31

5.9 Confirmation of the operation of further protective measures ............................................. 32

5.10 Confirmation of the polarity of mains plug wiring ................................................................. 32

5.11 Functional test ..................................................................................................................... 32

6 Documentation and evaluation of test ........................................................................................... 32

7 Test equipment .............................................................................................................................. 33

Annex A (informative) General guidance and rationale ....................................................................... 34

A.1 Intended audience ......................................................................................................................... 34

A.2 Rationale ....................................................................................................................................... 35

A.2.1 Clause 5 – Tests .................................................................................................................. 35

A.2.2 Subclause 5.3 – Measuring of protective bonding resistance ............................................. 35

A.2.3 Subclause 5.4 – Measurement of insulation resistance ...................................................... 35

A.2.4 Alternative method ............................................................................................................... 37

A.2.5 Differential method .............................................................................................................. 37

Annex B (informative) Schematics for test sequences ......................................................................... 38

Annex D (normative) Special National Conditions ............................................................................... 41

Bibliography ........................................................................................................................................... 42

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SIST EN 50678:2020
EN 50678:2020 (E)
European foreword

This document (EN 50678:2020) has been prepared by CLC/TC 85X “Measuring equipment for

electrical and electromagnetic quantities”.
The following dates are fixed:
• latest date by which this document has (dop) 2020-12-16
to be implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2022-12-16
standards conflicting with this document
have to be withdrawn

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

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SIST EN 50678:2020
EN 50678:2020 (E)
Introduction

This standard intends to provide a general test procedure to verify the effectiveness of the basic

protective measures for current-using equipment or appliances after they have been repaired, thus

ensuring the safety of people using repaired equipment.

This standard may be considered to support compliance with the European Directive 2009/104/EU

concerning the minimum safety and health requirements for the use of work equipment by workers at

work.

In general, the test procedure for verification of products after repair is the responsibility of the related

product technical committees. This document may be taken into consideration by product technical

committees if they need to take into consideration modified or additional tests for verification after

repairs for products falling within their scope.
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SIST EN 50678:2020
EN 50678:2020 (E)
1 Scope

This document specifies requirements for setting a uniform procedure to verify the effectiveness of the

protective measures for current-using equipment or appliances after they have been repaired.

This procedure is applicable to current-using equipment or appliances with a rated voltage above 25 V

AC and 60 V DC up to 1 000 V AC and 1 500 V DC, and currents up to 63 A, connected to final

circuits. They may be either pluggable equipment type A connected or permanently connected.

This document is not intended to replace test covered by safety standards nor product standards, for

example type tests, routine tests and acceptance tests.

This document assumes that the current-using equipment or appliances under consideration complies

with its related product standard, has been introduced on the market, has been in use, has failed, and

has then been repaired.

It intends to verify that operations for repairs have not jeopardized basic protective measures, for

example to verify the continuity of the protective conductor, the withstand capability of the insulation or

to verify that no metallic part is loose or is inadvertently inserted in the device.

This document does not apply to:
— recurrent tests defined in EN 50699;

— devices and equipment that are part of the fixed electrical installations. For these, tests for

verification after repair are covered by HD 60364-6;
— audio/video, information and communication technology equipment;
— uninterruptible Power Supply (UPS);
— charging stations for electro-mobility;
— power supplies;
— programmable Logic Controllers (PLC);
— power Drives;
— devices for EX-zones or for mining applications in general;
— products already covered by standards addressing similar topics such as:

— medical equipment covered by EN 60601-1. For these devices, tests for verification after

repair are covered by EN 62353;

— arc welding equipment covered by EN IEC 60974-1. For these devices, tests for verification

after repair are covered by EN 60974-4.
— machinery covered by EN 60204-1. For these devices, EN 60204-1 applies.
___________
Under preparation. Stage at time of publication: prEN 50699:2019.
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SIST EN 50678:2020
EN 50678:2020 (E)
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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.

HD 60364-6, Low-voltage electrical installations — Part 6: Verification (IEC 60364-4)

EN 61557 (series), Electrical safety in low voltage distribution systems up to 1 000 V AC and 1 500 V

DC — Equipment for testing, measuring or monitoring of protective measures (IEC 61557, series)

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp

NOTE Some of the definitions may differ from those in the product standards for type testing, as different

test methods are used.
3.1
electrical safety

protection within an equipment which limits the effects of electrical current on a user or other

individuals

Note 1 to entry: Safety is defined as freedom from unacceptable risk (refer to ISO 14971:2007, definition

2.24).
3.2
testing

visual control, measure and prove the electric equipment after repair to assure that equipment remains

safe to use
3.3
repair
means for restoration of the intended function of the equipment
3.4
(electrically) skilled person

person with relevant education and experience to enable him or her to perceive risks and to avoid

hazards which electricity can create
[SOURCE: IEC 60050-195:1998, 195-04-01]
3.5
electrical equipment

single apparatus using electrical energy and connected by plug or permanently connected to a final

circuit of the distribution system

Note 1 to entry: Equipment includes those accessories as defined by the manufacturer that are necessary to

enable the normal use of the equipment.
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SIST EN 50678:2020
EN 50678:2020 (E)
3.6
final circuit (of buildings)

electric circuit intended to supply directly electric current to current-using equipment or socket-outlets

[SOURCE: IEC 60050-826:2004, 826-14-03]
3.7
leakage current
current flowing from live parts of the equipment to earth

[SOURCE: IEC 60050-442:1998, 442-01-24 modified – the term has changed and a reference to the

absence of an insulation fault has been removed]
3.8
touch-current

electric current passing through a human body or through an animal body when it touches one or more

accessible parts of electrical equipment not connected to protective earth

[SOURCE: IEC 60050-195:1998, 195-05-21 modified – the wording of the definition has been

narrowed to electrical equipment not connected to protective earth]
3.9
protective conductor current

electric current which flows in a protective conductor and is frequency weighted according to the

characteristics of the human body

[SOURCE: IEC 60050-826:2004, 826-11-21, modified – the wording of the definition has been

expanded.]
3.10
residual current

vectorial sum of the currents flowing in the live conductors of the mains circuit of the equipment and

frequency weighted according to the characteristics of the human body

[SOURCE: IEC 60050-442:1998, 442-05-19 modified – the wording of the definition has been

expanded]
3.11
insulation resistance

resistance under specified conditions between two conductive elements separated by insulating

materials
[SOURCE: IEC 60050-151:2001, 151-15-43]
3.12
protective bonding resistance

resistance between any accessible conductive part, which has to be connected for safety purposes to

the protective earth terminal, and the
— protective terminal of the mains plug, or
— protective terminal of the equipment inlet, or
— protective terminal permanently connected to the supply mains,

resistance between protective earth terminals at each end of a detachable power supply cord,

extension leads and multi-way adapters
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SIST EN 50678:2020
EN 50678:2020 (E)
3.13
SELV

electric system in which the voltage cannot exceed the value of extra-low voltage:

— under normal conditions and

— under single fault conditions, including earth faults in other electric circuits

Note 1 to entry: SELV is the abbreviation for safety extra-low voltage.
[SOURCE: IEC 60050-826:2004, 826-12-31]
3.14
PELV

electric system in which the voltage cannot exceed the value of extra-low voltage:

— under normal conditions and
— under single fault conditions, except earth faults in other electric circuits
Note 1 to entry: PELV is the abbreviation for protective extra-low voltage.
[SOURCE: IEC 60050-826:2004, 826-12-32]
3.15
permanently connected equipment

equipment that can only be electrically connected to or disconnected from the mains by the use of a

tool
3.16
pluggable equipment type A

equipment that is intended for connection to the mains via a non-industrial plug and socket outlet or

via a non-industrial appliance coupler, or both

Note 1 to entry: Examples are plugs and socket-outlets covered by standards such as IEC/TR 60083 and

EN 60320-1.
3.17
current-using equipment

electric equipment intended to convert electric energy into another form of energy, for example light,

heat, mechanical energy
[SOURCE: IEC 60050-826:2004, 826-16-02]
3.18
hazardous-live-part
live part which, under certain conditions, can give a harmful electric shock
[SOURCE: IEC 60050-826:2004, 826-12-13]
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SIST EN 50678:2020
EN 50678:2020 (E)
4 Requirements
Tests after repair shall only be performed by an electrically skilled person.

Additional requirements (e.g. for the mechanical safety or for fire protection) according to the

requirements from the product safety standard shall be considered.

If testing the equipment requires additional knowledge or additional test and test equipment, for

example equipment for microwaves, tests shall be done according to the instructions of the

manufacturer.

All tests shall be performed in such a manner that the risk for testing personnel or other individuals

shall be reduced by appropriate protective measures.

If not otherwise stated, all values for current and voltage are the RMS values of an alternating, direct

or composite voltage or current.
The applicable tests as listed in Clause 5 shall be used to advise that:

— there are no visible faults on safety related parts, which are accessible by the user, and

— by the intended use of the equipment, no hazard for the user or the environment originates.

The electrically skilled person who is responsible for the test shall decide if additional tests are

required to meet the protective measures.

The electrically skilled person may decide that, for equipment that is connected to the distribution

system with fixed and protected wiring and is not intended to be hand-held during operation, the test is

carried out according to this standard and/or according to HD 60364-6.

The test procedure shall be interrupted, and the equipment shall be disconnected from mains and

marked as failed, if it is found that during the test:
— reduced safety levels are present due to damage or from unintended use, and/or
— functional hazards could occur.
5 Tests
5.1 General
5.1.1 General test conditions

The tests may be performed at the ambient temperature, humidity and atmospheric pressure present

at the location of testing. The operational limits of the test equipment and the equipment under test

(EUT) shall be considered.

The test equipment shall be tested according to the test steps in 5.1.2 to 5.1.5, as long as it is possible

with the EUT. The sequence of testing shall be as defined in this standard.
For schematics of test sequences, see Annex B.
Each individual test shall be passed before proceeding to the next test.

If it is not possible to perform a certain test step, an electrically skilled person shall decide if the safety

of the EUT can be confirmed without the test step or by other means.

NOTE 1 Manufacturer’s instructions on tests to be performed after repair can be considered as other means.

The values in this standard shall be used unless the product standard specifically provides in-service

limits in which case the product standard limits shall be used.
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SIST EN 50678:2020
EN 50678:2020 (E)

NOTE 2 If other external equipment is connected to the EUT, for example via data connectors, measured

values will be for the total system including the external equipment or accessories. If the external equipment is

disconnected from the mains but remains connected to the EUT, measurements can still be influenced such that it

is not possible to correctly access the safety of the EUT.

If it is obvious that the EUT is contaminated by dust or moisture, it is allowed to clean the EUT and/or

the EUT is allowed to dry before starting the tests.
5.1.2 Visual inspection
Visual inspection shall be performed according to 5.2.
5.1.3 Test of the protective measures against electric hazards

Test of the protective measures against electric hazards shall be performed according to 5.3 to 5.8.

— Confirmation of the effectiveness of the protective bonding to all accessible conductive parts

connected for safety reasons to protective earth according to 5.3.

— Confirmation of the effectiveness of the insulation by measuring the insulation resistance between

live parts and accessible conductive parts:

— connected to protective earth (primarily on class I equipment) according to 5.4;

— protected by double or reinforced insulation and not connected to protective earth (primarily

on class II equipment but also on class I equipment) according to 5.4;
— protected by SELV/PELV according to 5.4.

— Confirmation of the compliance with the limits for the leakage currents by measuring of:

— the protective conductor current according to 5.5;

— The touch-current of accessible conductive parts not connected to protective earth, if

applicable, according to 5.6.

NOTE 1 The measurement of leakage current can be omitted on extension leads, detachable power cables,

multiple socket-outlets without electrical parts between live conductors and protective earth.

NOTE 2 In general this standard does not address the measurement of DC leakage currents.

— Confirmation of the compliance with the requirements for the protective measure SELV/PELV by

measuring the output voltage, if the output voltage is accessible according to 5.7.

— Confirmation of the compliance with the limits for the leakage currents produced by a floating

input with a rated input voltage above 50 V AC or 120 V DC according to 5.8.

— Confirmation of the compliance of the polarity of mains plug wiring according to 5.11.

5.1.4 Confirmation of the compliance of additional protective measures

Confirmation of the compliance of additional protective measures shall be according to 5.9.

5.1.5 Documentation and evaluation of test

The documentation and the evaluation of the tests shall be according to Clause 6.

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EN 50678:2020 (E)
5.2 Visual inspection

The visual inspection shall take place to detect external defects and, if possible, to determine the

qualification of the suitability of the equipment for the environment.
Special attention shall be paid to the following (if any):
— any damage or contamination;
— all cables and connectors fulfil the requirements of their intended use;
— condition of the mains plug and the mains connectors and conductors;
— defects of the strain relief of the mains supply cord;
— defect of the mains lead cleat;
— condition of anchorage, cable clip, accessible fuse insert;

— damage of the housing and protective cover that may give access to live or dangerous moving

parts;
— signs of overload or overheating or unintended use;
— signs of improper change;
— signs of contamination, corrosion and improper aging;
— contamination, blockage of cooling inlets;
— condition of air filter;

— density of container for water, air, or other medium, condition of pressure control valve;

— usability of switches, control and setup equipment;

— readability of all safety relevant markings or symbols, of the ratings and of the position indicators;

— all fuses accessible from the outside are complying with the data given by the manufacturer (rated

current, characteristics);
— the integrity of mechanical parts;

— assess the relevant accessories together with the equipment (e.g. detachable or fixed power

supply cords tubing);
— defect due to over-bending of cords, cables, hoses and tubing.

NOTE It is appropriate to determine during the visual inspection, if accessible conductive parts, that have to

be tested according to 5.3 to 5.8, are present.
5.3 Measurement of protective bonding resistance
The integrity of the connection between:

— the protective earth terminal of the equipment (where applicable contact on the mains plug) and

— each accessible conductive part intended to be connected to the protective earth. Additional

confirmation is needed for all parts that are visible during repair.
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EN 50678:2020 (E)
The integrity of those connections shall be confirmed by:

— visually inspecting the entire length of the protective earth path according to 5.2;

— measuring the resistance of each protective terminal; and

NOTE 1 During the measurement the conductor is flexed over the entire length and at the point of entry on the

equipment and the mains plug.

— checking by hand to ensure that the anchorages and the inlets of each connector are properly

fixed.
Test circuits according to Figure 1a or Figure 1b may be used.

For cable lengths up to 5 m and a cross section area up to 1,5 mm , the protective bonding resistance

shall not exceed 0,3 Ω. For each further 7,5 m cable length 0,1 Ω shall be added to the limit up to a

maximum value of 1 Ω.

For cross section areas above 1,5 mm and other cable lengths the limit shall be calculated by the

following formula:
R= p+Ω0,1 or R= +Ω0,1
A κA
where
R is the electrical resistance (Ω);

ρ is the standard value of electrical conductivity (m/(Ω mm2) for the metal used for the PE

conductor;
l is the length of the cable in meters (m);
A is the cross-sectional area of the conductor in square millimetres (mm );
κ is the electrical conductivity (m/(Ω mm ).

NOTE 2 The value of 0,1 Ω in the equation above considers the influence of the contact resistance.

It is recommended that care be taken to ensure that the contact resistance between the test probe and

the metal part under test does not influence the test result.

When equipment is permanently connected to the distribution system, an earth reference point on the

fixed installation is required to measure the earth continuity. The protective earth conductor shall not

be disconnected from the installation and protective covers shall not be removed.

NOTE 3 During this measurement parallel earth connections, for example due to the type of installation (water

pipe or data line), can influence the result.

Some equipment may have accessible metal parts which are earthed only for functional or screening

purposes with protection against electric shock being provided by double or reinforced insulation. It is

important that these non-safety earthed metal parts are not subjected to a high current test otherwise

damage may result.
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SIST EN 50678:2020
EN 50678:2020 (E)
Key for all Figures 1 to 4
G generating measuring supply
PE Protective Earth
L Live
MΩ Ohm meter
N Neutral
U Measured voltage
1 measuring device
2 equipment under test (EUT)
3 fuse or circuit breaker
4 socket
5 N (neutral) or live interrupted
6.1 test point(s), accessible conductive parts, connected to PE
6.2 test point(s), accessible conductive parts, not connected to PE
7 earth potential
8 equipment is isolated from earth

9.1 test probe to protective earth and to accessible protective parts, connected to PE

9.2 test probe to protective earth and to accessible protective parts, not connected to PE

9.3 test probe to live parts
10 possible parallel earth connection
11 double or reinforced insulation

Figure 1a — Example of test circuit for the measurement of protective earth resistance in

equipment that is disconnected from the supply mains
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EN 50678:2020 (E)

Figure 1b — Example of test circuit for the measurement of protective earth resistance in

equipment, which for functional reasons cannot be disconnected from supply mains, or in

equipment or permanently connected to mains
5.4 Measurement of the insulation resistance
The insulation resistance shall be measured:

— between live parts and each accessible conductive part, including protective earth (except PELV);

— between live parts of a SELV/PELV circuit and live parts of mains supply, if affected by the repair.

Test circuits according to Figure 2a to Figure 2f may be used.

The test circuits and limits in Table 1 shall be used. The EUT shall be disconnected from mains supply.

To include all insulation of all live parts, all switches, controls etc. shall be closed during the

meas
...

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