Contents Page

European foreword 4

Introduction 5

1 Scope 6

2 Normative references 6

3 Terms and definitions 7

4 Installation of test stations 10

4.1 Overview of different types of test stations 10

4.2 Requirements for the operating status 11

4.2.1 Out of operation 11

4.2.2 Ready for operation 12

4.2.3 Ready to switch on 12

4.2.4 In operation 12

4.2.5 Specific requirement for test stations lower and equal 1 000 V 12

4.3 Indicator lights, signal lights and signs for indicating the status of operation 12

4.4 Test setup 13

4.4.1 Requirement for protection against direct contact 13

4.4.2 Measuring and auxiliary devices 14

4.4.3 Requirements for fault protection 15

4.4.4 Barriers, danger area 15

4.4.5 Reliability of the control circuits 17

4.4.6 Requirements for the emergency switching off 17

4.4.7 Preventing unauthorized and unintentional switching-on 17

4.4.8 Preventing automatic energizing 17

4.4.9 Protection against residual voltages and transfer of voltages 18

4.4.10 Protective measures against other hazards 18

4.5 Test stations with automatic protection against direct contact 18

4.5.1 General 18

4.5.2 Test station with automatic protection against direct contact in non-enterable design 18

4.5.3 Test station with automatic protection against direct contact in enterable design 18

4.6 Test stations without automatic protection against direct contact 19

4.7 Extraordinary test stations 19

4.7.1 Temporary test station 19

4.7.2 Test laboratories 20

4.8 Test station without test personnel in permanent attendance 21

4.9 Additional requirements when using safety test probes 21

4.10 Testing of ready-to-use products 22

5 Operation of test stations 23

5.1 General 23

5.2 Personnel 23

5.3 Preparation of tests, switching operations in test stations 23

5.4 Performance of tests 24

Annex A (informative) Permissible body currents and contact voltages 26

Annex B (informative) Example of an test setup illustrating the prohibition zone and danger area 27

Annex C (informative) Summary of requirements for the different variants of test stations 29

Bibliography 33

Figures

Figure 1 — Overview of a test station with operating and danger areas 11

Figure 2 — Clarification of the dimensions stated in Table 2 16

Figure 3 — Measurement of discharge current 22

Figure B.1 — Prohibition zone and danger area in a test laboratory 28

Tables

Table 1 — Prohibition zone (s) dependent on test voltages to earth (U) 14

Table 2 — Horizontal distance between the barrier and the prohibition zone in relation to the height of the barrier and the distance of the danger point from the floor 16

Table 3 — Minimum distance between openings in the barrier and the prohibition zone in relation to the width of the opening 17

Table A.1 — Reference values for permissible sinusoidal body currents and contact voltages at frequencies > 500 Hz 26

Table C.1 — Requirements for test stations with automatic protection against direct contact 29

Table C.2 — Requirements for test stations without automatic protection against direct contact 31

European foreword

This document (prEN 50191:2026) has been prepared by CLC BTTF 128‑2, “Erection and operation of electrical test equipment”.

This document is currently submitted to the Enquiry.

The following dates are proposed:

This document will supersede EN 50191:2010.

prEN 50191:2026 includes the following significant technical and editorial changes with respect to EN 50191:2010:

— update of the title;

— improvement of structure Clause 4 and renumbering;

— improvement of the wording;

— add some figures for clarification;

— creation of new Annex C;

— update the normative references.

Introduction

With reference to Clause 5 of this document, prepared in the field of application of Article 137 of the EC Treaty, the user should be aware that standards have no formal legal relationship with Directives which may have been made under Article 137 of the Treaty. In addition, national legislation in the Member States may contain more stringent requirements than the minimum requirements of a Directive based on Article 137 of the Treaty. Information on the relationship between the national legislation implementing Directives based on Article 137 of the Treaty and this document may be given in a national foreword of the national standard implementing this document.

This standard applies to development and production testing activities prior to providing the test items to the Union market as well as to measurements and tests in research and development (R&D).

Unless other regulations or procedure are available, the principles of this standard can be applied to other testing and measurement tasks as well.

1.1 This document is applicable to the installation and operation of fixed and temporary electrical test installations.

1.2 Compliance with this document needs to be applied, if contact with live parts presents dangerous. This is the case when:

a) the voltage exceeds 25 V AC (frequencies lower than 500 Hz) or 60 V DC and current exceeds 3 mA for AC or 12 mA for DC, or

b) the voltage exceeds 25 V AC (for any frequency) or 60 V DC and the discharge energy of the test station and test object exceeds 350 mJ, or

c) at frequencies above 500 Hz the national determined current and voltage values are applied. If there are no national requirements, determined reference values for permissible body currents and contact voltages can be taken from Table A.1;

This document is applicable even if conditions a) to c) are fulfilled, due to other possible risks, e.g. risk of fire or explosion.

NOTE The values for the resultant current of 3 mA AC or 12 mA DC comply with the information about the effects of current on human beings and livestock in IEC/TS 60479‑1.

1.3 Some specifications in this document refer to a voltage value of 1 000 V. This value applies to AC voltages and is equated to a value of 1 500 V DC voltage.

1.4 Where no requirements are given in this document, the documents of the HD 60364 series (for nominal voltages up to 1 000 V) or EN IEC 61936‑1 and EN 50522 (for nominal voltages exceeding 1 kV) apply to the installation of electrical test installations and EN 50110‑1 applies to the operation of electrical test installations.

1.5 This document does not apply to the power supply to the test installations. In this case, the documents of the HD 60364 series (for nominal voltages up to 1 000 V) or EN IEC 61936‑1 (for nominal voltages exceeding 1 kV) apply to their installation and EN 50110‑1 applies to their operation.

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.

EN 50110‑1:2023, Operation of electrical installations - Part 1: General requirements

EN 60529, Degrees of protection provided by enclosures (IP Code ) (IEC 60529)

EN 61010‑031, Safety requirements for electrical equipment for measurement, control, and laboratory use - Part 031: Safety requirements for hand-held and hand-manipulated probe assemblies for electrical test and measurement (IEC 61010-031)

EN 61140:2016, Protection against electric shock - Common aspects for installation and equipment (IEC 61140:2016)

EN ISO 13850, Safety of machinery - Emergency stop function - Principles for design (ISO 13850)

EN ISO 13851:2019, Safety of machinery - Two-hand control devices - Principles for design and selection (ISO 13851:2019)

EN IEC 61558‑2‑4, Safety of transformers, reactors, power supply units and combinations thereof - Part 2-4: Particular requirements and tests for isolating transformers and power supply units incorporating isolating transformers for general applications (IEC 61558-2-4)

EN IEC 61558‑2‑6, Safety of transformers, reactors, power supply units and combinations thereof - Part 2-6: Particular requirements and tests for safety isolating transformers and power supply units incorporating safety isolating transformers for general applications (IEC 61558-2-6)

ISO 7010:2019,^[1] Graphical symbols - Safety colours and safety signs - Registered safety signs

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

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

— IEC Electropedia: available at https://www.electropedia.org/

— ISO Online browsing platform: available at https://www.iso.org/obp

3.1

electrical test installation

test installation

test devices, test appliances and facilities combined for test purposes, by means of which electrical tests are performed on test objects

Note 1 to entry: Equipment including, but not limited to, measuring instruments, software, consumables, auxiliary apparatus or earthing rods.

3.2

test setup

area which includes the test installation and the test object

3.3

test station

appropriately identified test installation within a defined area

3.3.1

test station with automatic protection against direct contact

test station in which the test object and all live parts of the test station have automatically activated full protection against direct contact in an energized condition

Note 1 to entry: At a test station with automatic protection against direct contact, there is generally only one person employed, e.g. in the line of series production or in electric workshops, repair and service shops.

Note 2 to entry: Automatic protection means that voltages can only occur when the safety devices are effective, e.g. when the cover or door of the test station is closed.

3.3.2

test station without automatic protection against direct contact

test station in which parts of the test object or live parts of the test installation are not fully protected against direct contact during testing

Note 1 to entry: Test station without automatic protection against direct contact includes, for instance, test stations in electric workshops, laboratories, measurement and experimental test stations.

Note 2 to entry: Test station without automatic protection against direct contact can be designed as stationary or non-stationary.

3.3.3

enterable test station

test station where the test area can be entered by person (e.g. walked in)

3.3.4

non-stationary test station

test station for carrying out tests on individual test objects with different local conditions and at different locations over the time

3.4

test laboratory

delimited area with restricted access for the operation of at least one test station, in which more than one person are usually performing with the testing of test objects for longer periods of time

3.5

prohibition zone

volume around live parts which should not be reached if full protection against direct contact with these parts is not provided

Note 1 to entry: “prohibition zone” a reference to Annex B.

3.6

signal light

light which are clearly visible from outside the boundaries of the danger area giving red or green signals to indicate the operational status inside the danger area

3.7

indicator lights

visual indication of the switching or operating status on the control panels

3.8

risk

combination of the probability of occurrence of harm and the severity of that harm

Note 1 to entry: The term “harm” in this context relates to damage to either persons and/or test installations.

[SOURCE: IEC 60050‑351:2013, 351-57-03 modified, Note 1 to entry was added.]

3.9

electrical hazard

potential source of harm when electric energy is present in an test installation

Note 1 to entry: The term “harm” in this context relates to damage to either persons and/or test installations.

Note 2 to entry: In electrical test stations electrical hazards can caused by the test object and the test installation.

Note 3 to entry: This entry was numbered 651–01–30 in IEC 60050‑651:1999. It has been modified to follow the new translation of ISO/IEC Guide 51 and to precise the term “harm”.

[SOURCE: IEC 60050‑651:2014, 651-26-05 modified, by, replacing the word “electrical” with the word “test”; adding a new Note 2 to entry; former Note 2 to entry renumbered to Note 3 to entry]

3.10

skilled person

<electricity> person with relevant education, knowledge and experience to enable them to analyse risks and to avoid hazards which electricity can create

[SOURCE: IEC 60050‑651:2014, 651-26-11, modified, the term “training” was deleted,” perceive” was replaced by “analyse”; “danger” was replaced by “hazard”]

3.11

instructed person

<electricity> person adequately advised by skilled persons to enable them to perceive risks as instructed and to avoid hazards which electricity can create

[SOURCE: IEC 60050‑651:2014, 651-26-12 modified, the term “supervised” was deleted, “electrically” was deleted “danger” was replaced by “hazard” and added “as instructed”]

3.12

test controller

TC

designated skilled person with direct management responsibility for conducting the test at the test station

Note 1 to entry: Parts of this responsibility may be delegated to others as required.

3.13

danger area

area composed from prohibition zone and protective distance

3.14

protective distance

required horizontal distance from the prohibition zone

Note 1 to entry: see Table 2 and 3

3.15

operating area

area from which the test system can be safely operated (without reaching the prohibited zone)

3.16

emergency switching-off

opening operation intended to remove electric power from the electrical test station to avert or alleviate a hazardous situation

[SOURCE: IEC 60050‑826:2014, 826-17-03, modified by delete “a switching device” and replace installation by test station]

3.17

test object

item submitted to a test, including any accessories, unless otherwise specified

[SOURCE, IEC 60050‑151:2014, 151-16-28]

3.18

safety test probe

IP2X probe tips with retractable sleeve

Note 1 to entry: further information is given in EN IEC 61010‑031:2022, 7.4.3.5

Note 2 to entry: (German version only) this device is called “high voltage safety test probe” (Hochspannungsprüfpistole).

Test stations are divided into different variants with corresponding requirements. A high priority is given to protection against direct contact.

They are designed with or without automatic protection against direct contact.

Typical test stations are:

• test stations with automatic protection against direct contact:

o test station with non-accessible danger area (Test cage, test enclosure, test cabinet);

o test station with accessible danger area (Test cabin);

o test station without permanent presence of personnel (e.g. endurance test);

• test stations without automatic protection against direct contact:

o for development and repair;

o for series production with two-hand control device;

o high voltage test with safety test probes;

o temporary test station;

o without permanent presence of personnel, e.g. for endurance tests.

An overview of the different requirements for different types of test stations is given in Annex C.

The overview of the a station is composed of different areas as shown in Figure 1.

Key

1 test object, here envelope around a live object, 2 200 mm high

2 prohibition zone

3 danger area

4 operating area

5 barrier constructed as a bar tape, chain or rope, 1 000 mm high

6 barrier, 2 400 mm high

7 control panel

Figure 1 — Overview of a test station with operating and danger areas

This includes:

a) all power supplies, signalling and control circuits are switched off and secured against unauthorized switching-on;

b) all safety precautions necessary before entering the danger area e.g. for voltages exceeding 1 kV, earthing, short-circuiting have been taken.

This includes:

a) the power supplies for the switchgear signalling and control circuits of the test installations are switched on;

b) the green signal lights, where these are required in accordance with the provisions in Clause 4, are on;

c) all power supplies for the test voltage are switched off and secured against unintentional switching;

d) the safety precautions specified in 4.2.1 b) are in force.

This includes:

a) all power supplies for the test voltage are switched off;

b) all entries to the danger area are closed;

c) the red signal lights are switched on;

d) the safety precautions specified in 4.2.1 b) are no longer in force.

This includes:

a) all entries to the danger area are closed;

b) the red signal lights are switched on;

c) one or more power supplies for the test station are switched on.

In Clauses 4 and 5, the technical devices for setting up the operational status Ready to switch on (4.2.2) and Ready to switch on (4.2.3) are only required for certain test installations with voltages exceeding 1 kV.

In test stations lower and equal 1 000 V the requirements of Ready for operation (4.2.2) and Ready to switch on (4.2.3) can be omitted.

Control devices for the test installation and the test circuits shall be clearly identified.

Test installations shall have means, e.g. indicator lights, which indicate the switching status, e.g. position of earthing switches or status of components.

The operating status can additionally be indicated by indicator lights or other means.

The signal lights for indicating the status of operation are based on the following:

a) any safe operation status indicated by green signal lights;

b) any non-safe operation status is indicated by red signal lights.

According to a risk assessment the status of Ready to switch on (4.2.3) can be indicated by orange signal light.

If the risk assessment requires the differentiation of operational status Ready to switch on (4.2.3) and In operation (4.2.4), it is recommended in this case to indicate the operational status In operation (4.2.4) by a blinking red signal light. The blink frequency shall not be below 1 Hz.

Indicator lights may be replaced by indicators on displays or similar display devices.

Indicator lights are not an alternative to required signal lights.

Test installations and danger areas shall be clearly and visibly indicated by means of warning signs.

The test setup shall be arranged and designed that the protection against direct contact is provided by:

– insulation of live parts; or

– covers, enclosures (min. IPXXB or IP 2X according to EN 60529); or

– obstacles or safe distances.

A safe distance is ensured, when the person carrying out the tests cannot reach the prohibition zone with parts of them body or tools.

The boundary of the prohibition zone shall be determined in accordance with Table 1.

In case of voltages up to 1 000 V, the surface of the live part is considered to be the boundary of the prohibition zone. In case of voltages exceeding 1 kV, reaching the prohibition zone is considered equal to touching live parts.

The protection for reaching the prohibited zone can also be fulfilled by using two safety test probes. Safety test probes shall have the adequate insulation level for the applied test voltage. Measures which prevent the automatic return of the contact tip after release the two hand control switches are not permitted.

Safety can also be satisfied by means of a two-hand control device. Test leads with full protection against direct contact shall be used. Two-hand control devices shall comply with EN ISO 13851:2019, Type II or IIIB.

Where several persons are involved in a test, a two-hand control device shall be provided for each person of the test personnel, connected in such a way that all two hand controls shall be operated before the test supplies can be energized.

The test object shall be isolated from earth, e.g. by using test tables with surfaces of insulating materials. If this is not technically possible, e.g. due to the weight of the test object, or if the test method requires earthing, the test setup shall be designed and arranged in such a way that the transfer of voltage to extraneous conductive parts is prevented.

The surfaces of test table boards shall be made of insulating materials.

Table 1 — Prohibition zone (s) dependent on test voltages to earth (U)

If measuring and signal circuits shall be operated free of earth potential when using measuring and auxiliary devices of protection class I in accordance with EN 61140:2016, 7.3, e.g. cathode ray oscilloscope, sine wave voltage generator, measuring transformers with galvanic isolation should preferably be used.

If this is not possible for test reasons, e.g. because the housing is to be isolated from earth potential, the mains connection of the measuring and auxiliary device shall be made via an isolating transformer that complies with standards EN IEC 61558‑2‑4 or EN IEC 61558‑2‑6.

The internal insulation of isolating transformers and instrument transformers shall be rated at least for the expected voltages to earth.

An effective protective measure for fault protection (protection against indirect contact) shall be provided (see HD 60364‑4‑41:2017, 411.3).

4.4.4.1 Test stations shall be separated from other work areas and passageways. The barriers shall be designed as to

— prevent access to the test station by persons other than the test persons,

— prevent persons, other than the test persons, from reaching the prohibition zone,

— prevent persons outside the barrier from reaching the operating devices of test installations which are located inside the barrier.

The minimum distance to demarcate the danger area and the operating elements shall be determined in accordance with Figure 2 and Table 2. In case of grid barriers, the minimum distance between the barrier and the prohibition zone shall comply with Table 3 at any opening, where it is possible to reach through the banner.

Barriers made of conductive materials shall be earthed or other measures shall be taken for fault protection.

Table 2 — Horizontal distance between the barrier and the prohibition zone in relation
to the height of the barrier and the distance of the danger point from the floor

Key

a distance between the danger point and the floor (danger point is the point on the boundary of the prohibition zone having the shortest distance from the edge of the means of protection)

b height of the edge of the means of protection

c horizontal distance between the edge of the means of protection and the danger point

Figure 2 — Clarification of the dimensions stated in Table 2

Table 3 — Minimum distance between openings in the barrier and the prohibition zone
in relation to the width of the opening

4.4.4.2 The test station shall be designed in such a way that it can be left unhindered in the event of danger and accessed in an emergency.

NOTE Attention is drawn to national rules and regulations that can apply.

4.4.4.3 Mechanical means of protection shall be adequately strong.

In the operating states Out of operation (4.2.1) and Ready for operation (4.2.2), an appropriate reliability of the control circuit shall ensure that the test voltage is switched off.

NOTE EN ISO 12100, EN IEC 62061, ISO 13849 provide guidance on how the reliability of control circuits can be achieved.

Test installations shall be equipped with an emergency stop device that completely switches off the electrical supply to the circuits that cause hazards. The function shall be triggered even by a single action. For test circuits with residual voltages 4.4.8 shall be considered.

The devices or equipment for emergency stop shall be in accordance with the requirements of EN ISO 13850. The effective ranges of the emergency stop devices shall be precisely defined and labelled; effective ranges may overlap.Connection points, e.g. outlets of the general power supply within the danger area, shall be identified accordingly, if they are not interrupted by the emergency switching off equipment. The emergency stop devices shall be checked regularly for proper function.

A sufficient number of manual operating devices shall be provided inside and outside the danger area in accordance with the size of the area and the complexity of the arrangement.

Test installations shall be secured against unauthorized and unintentional switching-on of test circuits. Manual controls shall be clearly correlated to the respective test circuits.

Automatic energizing of test circuits shall be prevented when mains voltage recovers after a power failure.

If there is a likelihood of danger due to residual voltages greater than 25 V AC or 60 V DC or a discharge energy greater than 350 mJ after switching-off test circuits, suitable devices or equipment shall be provided and the residual voltage shall be relieved before active parts can be touched.

NOTE 1 The voltage can also be reduced over time or via automated devices.

For test voltages above 1 kV, earthing and short-circuiting devices shall be provided (see EN 50110‑1:2023, 6.2.5).

Transfer of voltage to accessible conductive parts outside the danger area shall be prevented by adequate measures – e.g. earthing, shielding, appropriate cable routing – or these conductive parts shall be protected against direct contact.

NOTE 2 Voltage carryover can be caused by capacitive or inductive interference and faults, among other things.

Appropriate means of protection shall be provided, in cases where in addition to dangers due to voltages other hazards are to be expected, e.g. due to arcs, noise, explosion, radiation, flying parts, formation of gas, fire, dangerous substances.

The protection against direct contact in accordance with 4.4.1 shall be satisfied by insulation of live parts, covers or enclosures. The means of protection against direct contact shall guarantee at least the defined degree of protection IPXXC in accordance with EN 60529 and include all parts of the test object.

It shall not be possible to switch on the test voltages until the means of protection are fully operational and functioning correctly. Opening the protective devices shall inevitably switch off the test voltage and discharge the residual voltages to a level lower than according to 1.2.

Single fault conditions in the safety circuit shall not prevent the test voltages from being switched-off and discharged when the means of protection are opened. The fault occurrence shall ensure that it is impossible to switch on the test voltages again. It shall not be possible to bypass the means of protection in an easy way.

If parts of the enclosure at the operation side are replaced by an electro-optical safety device (light barrier) with a beam distance of not more than 14 mm, then in this case, the degree of protection IPXXC may be omitted for this part of the enclosure. The safety distance between the detection zone of the electro-optical safety device and prohibition zone shall be large enough, so that the prohibition zone cannot be reached while breaching into the detection zone. While investigating the safety distances at least the test probe for the degree of protection IPXXC in accordance with EN 60529 (test probe 2,5) shall be applied. In addition, the approach speed and the required used tools and materials within the installation, the respond time of the protection device and switching devices shall be considered (see EN ISO 13855).

For test stations with automatic protection against direct contact, barriers in accordance with 4.4.4.1, emergency switching off devices in accordance with 4.4.6 and signal lights in accordance with 4.3 may be omitted.

The degree of protection against direct contact IPXXC may be omitted if the enclosure complies with the following requirements:

— means of protection for the automatic protection against direct contact shall be solid walls or barrier grids (side length or diameter of the openings not exceeding 40 mm) at least 1 800 mm high;

— the test enclosure shall be equipped with devices which do not permit doors to the danger area to be opened until the test voltage has been switched off and secured against being switched on again and – if necessary – earthed and short-circuited. It shall not be possible to disable these protective measures until the doors have been closed.

4.6.1 Test stations without automatic protection against direct contact shall only be installed if the installation of test stations with automatic protection against direct contact is not practicable, e.g.:

— due to frequently changing test duties;

— in case of varying types of test objects;

— in case of serious difficulties in performing the work;

— when test duties occur only occasionally.

4.6.2 The barriers in accordance with 4.4.4.1 can be e.g. walls, grids, tapes, ropes, chains or bars subject to national regulations. They shall be so designed that visual and audible contact with the operator can be maintained from outside at all times.

4.6.3 At least one emergency switching device shall be installed outside the danger areas.

4.6.4 An adequate number of red and green signal lights (see Annex B), indicating the operational status, shall be installed. The green signal lights are not required in case of voltages up to 1 000 V.

4.6.5 If test circuits are electrically connected to the general power supply system, additional protection shall be provided by means of a residual current protective device (RCD) at a rated residual current I_ΔN ≤ 30 mA. If the residual current includes DC. components, an appropriate RCD shall be used.

If, due to test tasks, an additional protection by means of a RCD is not possible, then a residual current monitoring device (RCM) with a rated residual current I_ΔN ≤ 30 mA shall be used. By exceeding the rated residual current the switch off time shall not exceed the switch off time of a RCD. A supply voltage breakdown of RCM shall cause a switch off of the test circuit.

4.6.6 Electrical equipment, e.g. measuring instruments, variable resistors, shall be incorporated in an effective protective measure for fault protection (protection against indirect contact). This also applies to the exposed conductive parts of test objects unless these parts of the test object are also included in the test, e.g. insulation test, leakage current test, see Figure 2. Electrical equipment with protective insulation or supplied by means of isolating transformers shall preferably be used.

4.6.7 The working area of test stations shall be such that movement of test personnel is not impeded.

NOTE Attention is drawn to national regulations that can apply.

4.7.1.1 Temporary stations shall always be installed in accordance with 4.1. Depending on the design, the requirements in 4.5 or 4.6 shall also be observed.

Entrances shall be provided with a warning sign e.g. “No access for unauthorized persons” (P080) in accordance with ISO 7010:2020 ^[2].

4.7.1.2 If, due to the size of the test object, the barrier in accordance with 4.4.3 are disproportionately complex to set up in sub-areas, warning and monitoring posts shall be used for these sub-areas (see 5.4.5). The monitoring areas shall be selected in such a way that they can be safely switched off in good time when approaching or entering the danger area.

4.7.1.3 Where the test voltages exceed 1 kV, all areas including those outside the danger area where capacitive charging is likely to take place, shall be separated by additional barriers for the duration of the testing.

4.7.2.1 The barrier of a test laboratory (see Annex B, Figure B.1, W1) shall be in accordance with 4.4.4.1, and shall be solid walls or grids (see Table 3) at least 1 800 mm high. Entrances shall be provided with a warning sign e.g. “No access for unauthorized persons” (P080) in accordance with ISO 7010:2020 ^[3]. In case of test voltages up to 1 000 V, the barriers may also be tapes, ropes, chains or bars which shall be fixed between 1 000 mm and 1 400 mm distance from the floor. The minimum distance to the floor (sagging) shall not drop below 800 mm. Solid walls or grids shall be at least 1 000 mm high.

The barrier of the individual operating areas (see Annex B, Figure B.1, W5) within the test laboratory can be omitted.

4.7.2.2 An adequate number of red and green signal lights (see Annex B), indicating the operational status, shall be installed. The green signal lights are not required in case of voltages up to 1 000 V.

In case of several test stations within the test laboratory,

— the operational status of each of test station shall be indicated by means of signal lights;

— red signal lights shall indicate “danger” for the entire test laboratory whenever the operational status Ready to switch on (4.2.3) or In operation (4.2.4) exists in at least one of the test station.

4.7.2.3 Emergency escape doors, gates, etc. shall be able to be opened from the inside of the test laboratory.

NOTE 1 Attention is drawn to national regulations on escape routes and emergency exits that can apply.

4.7.2.4 In test laboratories measures are required to prevent unauthorized entry and shall not hinder persons from leaving.

4.7.2.5 The requirements of 4.7.2.1 to 4.7.2.4 always apply. If, compliance with individual safety measures required by these subclauses are not compatible with the test (e.g. for research and development), the protection of personnel in danger areas shall be secured equally effective by other means or measures This shall be documented by risk assessment.

NOTE 2 This can be achieved e.g. with reference to 4.7.2.4 by continuous supervision of access to the danger area.

If a test station is intended for operation without the permanent presence of test personnel (e.g. for endurance tests) it shall be installed in accordance with 4.5 or 4.6.

For a test laboratory see 4.7.2 in addition with technical access control for authorized personnel. Emergency stop equipment in accordance with the requirements of EN ISO 13850 with an adequate number of manual controls shall be provided. Prevention of automatic energizing in accordance with 4.4.8 may be omitted, provided that this will not cause any hazards.

Safety test probes shall comply with EN IEC 61010‑031.

The high voltage side of the test apparatus shall be electrically isolated from the supply and insulated from earth, same applying to test probes and their leads.

The test object shall be isolated from earth. If this is not possible, e.g. a test standard requires earthing or due to other practical reasons, deviations are permitted if a risk assessment specifies alternative measures to protect against electric shock.

The RMS value of the leakage current of the test equipment on the high voltage side of the test apparatus shall not exceed 3 mA. This value shall not be exceeded even when a highly resistive connection is made between the high voltage side and earth, e.g. for adjustment of potential of a measuring instrument according to Figure 3, position a) and b) for measurement of both poles of the high voltage source.

Position a)

Position b)

Key

1 supply

2 high voltage measurement instrument

3 test object (isolated from earth)

4 protectic conductor (connecting point) of the test object

5 ammeter with an internal resistance (including a necessary external resistance) of 2 000 Ω
(equivalent resistance for test personnel)

6a/6b safety test probe

Figure 3 — Measurement of discharge current

The measures, required in 4.5.1, may be omitted in exceptional cases, if the test object and all live parts are fully protected against direct contact and a measure for fault protection (protection against indirect contact) is efficient for the test object and the test installation during the test.

Test station may only be operated under the control and supervision of a skilled person. This does not apply to test stations which have automatic protection against direct contact and comply with requirements of 4.5.1.

Test stations shall be provided with operating instructions. These shall contain the information required for safe operation.

The test stations used shall be inspected for externally visible damage or defects before use.

Test stations shall not be operated if there are signs of damage or defects liable to cause danger.

Only skilled persons shall be employed to maintain the test stations.

The proper condition and efficiency of the safety devices shall be checked by a skilled person at suitable intervals of time.

NOTE Attention is drawn to national regulations the procedures of inspection that can apply.

The result on these inspections shall be recorded.

5.2.1 Only skilled or instructed persons are permitted to perform electrical test stations. All personnel involved shall be instructed in the safety requirements, safety rules and company instructions applicable for their work. A written record of this instruction shall be kept. These instructions shall be repeated as necessary but minimum once a year. The personnel shall be required to comply with the requirements, rules and instructions. The complexity of the work activity shall be assessed before the activity starts such the appropriate choice of a skilled or instructed person is made for carrying out the activity.

5.2.2 Personnel using safety test probes shall receive additional training regarding special risks involved.

5.2.3 A test controller (TC) shall be appointed for the respective test. If several persons are working at the same time at the same test station, some of the duties of the test controller (TC) can be delegated to other persons as required.

5.2.4 Test stations shall only be entered by the personnel employed there and other persons who have received adequate instruction regarding the hazards.

If other persons have to enter these areas, they shall be accompanied by a skilled person and their attention shall be drawn to the risks. In case of test stations with voltages exceeding 1 kV, the permission of the test controller (TC) is also required.

5.2.5 Any person working in test laboratories or in areas with temporary test stations shall be fully aware of the existing hazards and has the duty to take safety precautions in them work in order to protect both themself and other persons against hazards.

5.3.1 If the enclosure of a measuring instrument or an auxiliary appliance is connected to live parts of the test assembly and if as a result the enclosure can be exposed to a voltage exceeding 25 V AC or 60 V DC to earth, then adequate external insulation of the enclosure including the control device shall be provided. In special cases, procedures for live working shall be used (see EN 50110‑1:2023, 5.4).

5.3.2 When using safety test probes, the person carrying out the test shall visually check the test probes and their leads before starting work to ensure that they are safe to use.

5.3.3 If there is a likelihood of danger due to arcing, adequate measures shall be taken for the protection of personnel.

5.3.4 If, in addition to electrical hazards, other risks are likely to occur during tests and experiments, e.g. noise, explosions, radiations, flying parts, gas formation, fire or hazardous materials, additional safety measures shall be taken to ensure adequate protection.

5.3.5 The test controller (TC) shall make sure that their instructions are carried out correctly before the equipment

— is switched on, in case of voltages up to 1 kV,

— is made Ready to switch on (4.2.3) in case of voltages exceeding 1 kV.

5.3.6 Orders for switching operations may only be given by a test controller (TC). In test laboratories and temporary test installations with voltages exceeding 1 kV, switching operations may only be performed upon the personal order of the test controller (TC), when them does not perform this duty themself.

5.3.7 The test controller (TC) shall ensure that all persons other than test persons have left danger area before the test installation is

— switched on, in case of voltages up to 1 kV,

— made Ready for operation (4.2.2) in case of voltages exceeding 1 kV.

For test stations with accessible danger area, all persons shall leave the danger area before the test station is made Ready to switch on (4.2.3).

When using safety test probes all persons other than test persons shall have left the danger area before the test station is made Ready to switch on (4.2.3).

In case of test laboratories, experimental stations and temporary test installations with voltages exceeding 1 kV, all persons shall leave the danger area before the test installations are made Ready to switch on (4.2.3).

5.3.8 The person carrying out the test shall be able to recognize the operational status at any time, especially when several voltages are supplied.

Before leaving the test installations, the Out of operation (4.2.1) condition shall be established. This does not apply to test installations without the permanent presence of test personnel (see 4.9).

5.4.1 Assembly and setup of test object shall not be done simultaneously with the performing tests.

5.4.2 In exceptional cases, contrary to the requirements of 5.3.7, paragraph 3, skilled persons may enter the danger area in the operational status Ready to switch on (4.2.3) or In operation (4.2.4). Measures shall be taken to ensure that the prohibition zone is not reached (see EN 50110‑1:2023, 4.1).

Work activities carried out in the prohibition zone (live working) shall comply with the requirements of EN 50110‑1:2023, 6.3.

5.4.3 In the event of a fault during tests, parts of the test object and test installations which are not live during normal operation can be subjected to dangerous voltages. If, in exceptional cases, work has to be carried out on these parts, suitable insulating devices and auxiliary means shall be used (see EN 50110‑1:2023, 4.6).

5.4.4 In a test station without automatic protection against direct contact, as a safety measure during the operational status Ready to switch on (4.2.3) and In operation (4.2.4), at least one other person shall be present in visual and audible contact with the person carrying out the test and be in the position to recognize any dangerous conditions in the test station immediately and eliminate the danger by actuating the emergency switching off device.

5.4.5 If a temporary station is separated from generally accessible areas only by means of tapes, ropes, chains or bars, the following conditions apply in addition to the other requirements of Clause 5:

a) the entire test assembly shall be under surveillance during the test procedure. If this cannot be ensured by the person carrying out the test, a sufficient number of at least instructed persons shall be present to supervise the entire danger area and to take immediate action in the event of danger;

b) in case of test assemblies with several separate danger areas, e.g. when testing installed cables, one person is required to guard each area. Communication with the testing person or with the test controller (TC) shall be ensured. In these cases, while testing installed cables and lines, signal lights are not required in the area under surveillance.

5.4.6 Before touching test objects which have been switched off, it shall be ensured that voltages are at a level lower than according to 1.2 and no residual charges are present on the accessible parts.

The earthing and short-circuiting of the test object should be preferred.

In justified individual cases, earthing may be omitted., e.g. by test installation with isolated source.

5.4.7 Emergency routes and exits shall always be kept clear.

1. 
   (informative)
   
   Permissible body currents and contact voltages

Table A.1 has reference values for permissible sinusoidal body currents and contact voltages at frequencies above 500 Hz which are considered harmless under permanent exposure. If it is ensured that these values are not exceeded, measures in accordance with this document are not required (1.2 c). The permissible values in this table are the maximum permitted values under normal and dry conditions.

Table A.1 — Reference values for permissible sinusoidal body currents
and contact voltages at frequencies > 500 Hz

1. 
   (informative)
   
   Example of an test setup illustrating the prohibition zone and danger area

The prohibition zone V and the danger area G are illustrated by Figure B.1 showing the example of a test laboratory.

The danger area G is enclosed by the barriers W1, W2, W3 and W4. The distances c and d between the boundaries of the danger area G and the prohibition zone V shall be selected to ensure that persons are prevented from reaching the prohibition zone V from outside the barrier. The total distance between the boundary of the danger area G and the test object P results from the values stated in Table 1 and an additional margin relating to ergonomics in accordance with Table 2 or Table 3.

The striking distance x between the test object P and a solid barrier (e.g. solid wall W1) may be less than the distance s specified in Table 1. It shall, however, be larger than the striking distance x which is to be assumed at this point. Unless empirical values are available, it is recommended in case of AC test voltages to select the distance x > s/2 in accordance with Table 1. In the event of a voltage flashover to the solid barrier, care should be taken that no hazard occurs due to the formation of residual voltages.

The distance values for AC test voltages ranging from 1 kV to 1 000 kV stated in Table 1 are based on physical facts, taking into consideration extensive data published by a technical institution. The values have been increased by an additional safety margin so that an adequate safety can be guaranteed, even taking into account measurement uncertainties and an unfavourable air density.

The distance values given for the lightning impulse voltage of 1,2/50 µs are adequately rated so that these series of values allow to cover also the DC voltage up to 1 000 kV. The range selected from 20 kV to 1 500 kV covers all impulse voltage values up to 400 kV in accordance with EN IEC 60071 series.

The distance values for the boundary of the prohibition zone s given in Table 1 are applicable only to the voltage waveforms up to the maximum values specified. These distance values may possibly not suffice for other voltages (e.g. high frequency voltages, differing switching impulse voltages, DC and AC voltages superimposed with high frequency).

Key

P test object, here envelope around a live object, 2 200 mm high

V prohibition zone

G danger area

B operating area

Pu control panel

W barriers, separating the test station

W1 solid wall, height = headroom

W2 wire mesh, 2 400 mm high

W3 wire mesh, 1 800 mm high

W4 barrier constructed as a bar tape, chain or rope, 1 000 mm high

W5 barrier of the operating area

s distance according to Table 1

c horizontal distance according to Table 2

d distance according to Table 3

x distance > striking distance (= s/2)

Figure B.1 — Prohibition zone and danger area in a test laboratory

1. 
   (informative)
   
   Summary of requirements for the different variants of test stations

Table C.1 and Table C.2 explain the different requirements in regard of the different types of test stations. The short word “enterable” in the Table C.1 means the full term “enterable test station”.

Table C.1 — Requirements for test stations with automatic protection against direct contact

Table C.2 — Requirements for test stations without automatic protection against direct contact

Bibliography

Council Directive 92/58/EEC of 24 June 1992 on the minimum requirements for the provision of safety and/or health signs at work (ninth individual Directive within the meaning of Article 16 (1) of Directive 89/391/EEC), OJ L 245, 26.8.1992, p. 23–42

IEC 60050‑651:2014, International Electrotechnical Vocabulary – Part 651: Live working

IEC 60050‑826:2022, International Electrotechnical Vocabulary – Part 826: Electrical installations

EN 50522, Earthing of power installations exceeding 1 kV a.c.

EN ISO 13855, Safety of machinery - Positioning of safeguards with respect to the approach speeds of parts of the human body (ISO 13855)

HD 60364 series, Electrical installations of buildings/Low-voltage electrical installations (IEC 60364 series, mod.)

EN IEC 61936‑1, Power installations exceeding 1 kV AC and 1,5 kV DC - Part 1: AC

1. As impacted by ISO 7010:2019/A1:2020, ISO 7010:2019/A2:2020, ISO 7010:2019/A3:2021, ISO 7010:2019/A4:2021, ISO 7010:2019/A5:2022, ISO 7010:2019/A6:2022, ISO 7010:2019/A7:2023, ISO 7010:2019/A8:2024, ISO 7010:2019/A9:2025, ISO 7010:2019/A10:2025. ↑

2. Specifically in EN ISO 7010:2020/A10:2025. ↑

3. Specifically in EN ISO 7010:2020/A10:2025. ↑