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 - Part 7: Phase sequence

IEC 61557-7:2019 is available as IEC 61557-7:2019 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 61557-7:2019 specifies the requirements applicable to measuring equipment for testing the phase sequence in three-phase distribution systems. Indication of the phase sequence can be mechanical, visual and/or audible. This document does not apply to additional measurements for other quantities. It does not apply to monitoring relays. IEC 61557-7:2019 cancels and replaces the second edition published in 2007. This edition constitutes a technical revision. This edition includes the following changes with respect to the previous edition:
a) alignment of the structure with that of the whole IEC 61557 series;
b) updated requirements in 4.3 in accordance with new editions of IEC 61010-1 and IEC 61010-031;
c) the information on markings was extended;
d) the information on the operating instructions was extended;
e) complement to the information on the testing of leads;
f) test leads for insulated conductors were introduced;
g) Annex B was added with information on phase sequence tests and indications.

Sécurité électrique dans les réseaux de distribution basse tension au plus égale à 1 000 V c.a. et 1 500 V c.c. - Dispositifs de contrôle, de mesure ou de surveillance de mesures de protection - Partie 7: Ordre de phases

IEC 61557-7:2019 est disponible sous forme de IEC 61557-7:2019 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.L'IEC 61557-7:2019 spécifie les exigences applicables aux appareils de mesure destinés à soumettre à essai l'ordre des phases dans les réseaux de distribution triphasés. L'indication de l'ordre des phases peut être mécanique, visuelle et/ou audible. Le présent document ne s'applique pas aux mesures supplémentaires destinées à d'autres grandeurs. Elle ne s'applique pas aux relais de surveillance. L'IEC 61557-7:2019 annule et remplace la deuxième édition parue en 2007. Cette édition constitue une révision technique. Cette édition inclut les modifications majeures suivantes par rapport à l'édition précédente:
a) alignement de la structure sur l'ensemble de la série IEC 61557;
b) mise à jour des exigences définies au 4.3 par rapport aux nouvelles éditions de l'IEC 61010-1 et de l'IEC 61010-031;
c) développement des informations concernant le marquage;
d) développement des informations concernant les instructions de fonctionnement;
e) développement des informations concernant les essais des câbles;
f) les câbles d'essai pour conducteurs isolés ont été introduits;
g) l'Annexe B a été ajouté avec information sur l'essai d'ordre de phases et indication d'ordre de phases.

General Information

Status
Published
Publication Date
25-Jul-2019
Current Stage
PPUB - Publication issued
Completion Date
26-Jul-2019
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IEC 61557-7
Edition 3.0 2019-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electrical safety in low voltage distribution systems up to 1 000 V a.c. and
1 500 V d.c. – Equipment for testing, measuring or monitoring of protective
measures –
Part 7: Phase sequence
Sécurité électrique dans les réseaux de distribution basse tension au plus
égale à 1 000 V c.a. et 1 500 V c.c. – Dispositifs de contrôle, de mesure ou
de surveillance de mesures de protection –
Partie 7: Ordre de phases
IEC 61557-7:2019-07(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 61557-7
Edition 3.0 2019-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electrical safety in low voltage distribution systems up to 1 000 V a.c. and
1 500 V d.c. – Equipment for testing, measuring or monitoring of protective
measures –
Part 7: Phase sequence
Sécurité électrique dans les réseaux de distribution basse tension au plus
égale à 1 000 V c.a. et 1 500 V c.c. – Dispositifs de contrôle, de mesure ou
de surveillance de mesures de protection –
Partie 7: Ordre de phases
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.220.20; 29.080.01; 29.240.01 ISBN 978-2-8322-7161-2

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 61557-7:2019 © IEC 2019
CONTENTS

FOREWORD ........................................................................................................................... 3

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

2 Normative references ...................................................................................................... 5

3 Terms and definitions ...................................................................................................... 5

4 Requirements .................................................................................................................. 6

4.1 General ................................................................................................................... 6

4.2 Indication ................................................................................................................ 6

4.3 Measuring equipment .............................................................................................. 7

4.3.1 General ........................................................................................................... 7

4.3.2 Portable phase sequence indicator .................................................................. 7

4.3.3 Test leads for direct contact with live parts and accessories ............................ 7

5 Marking and operating instructions .................................................................................. 8

5.1 Marking ................................................................................................................... 8

5.2 Operating instructions ............................................................................................. 8

6 Tests ............................................................................................................................... 8

6.1 General ................................................................................................................... 8

6.1.1 Tests – General ............................................................................................... 8

6.1.2 Visual display .................................................................................................. 8

6.1.3 Audible indication (if applicable) ...................................................................... 8

6.2 Leakage current ...................................................................................................... 8

6.3 Test of mechanical requirements (type tests) .......................................................... 9

6.3.1 Mechanical shock test ..................................................................................... 9

6.3.2 Test of leads for direct contact with live parts .................................................. 9

6.4 Overvoltage ............................................................................................................ 9

6.5 Test of markings ..................................................................................................... 9

Annex A (normative) Illustrations for mechanical tests ......................................................... 10

Annex B (informative) Phase sequence test ......................................................................... 12

B.1 Phase sequence test – Tripolar connection ........................................................... 12

B.2 Phase sequence test – Sequential bipolar connection ........................................... 12

Bibliography .......................................................................................................................... 14

Figure A.1 – Mechanical shock test ....................................................................................... 10

Figure A.2 – Drop test ........................................................................................................... 11

Figure B.1 – Tripolar connection ........................................................................................... 12

Figure B.2 – Sequential bipolar connection ........................................................................... 13

---------------------- Page: 4 ----------------------
IEC 61557-7:2019 © IEC 2019 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
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 –
Part 7: Phase sequence
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

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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of

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

International Standard IEC 61557-7 has been prepared by IEC technical committee 85:

Measuring equipment for electrical and electromagnetic quantities.

This third edition cancels and replaces the second edition published in 2007. This edition

constitutes a technical revision.

This edition includes the following changes with respect to the previous edition:

a) alignment of the structure with that of the whole IEC 61557 series;
b) updated requirements in 4.3 in accordance with new editions of IEC 61010-1
and IEC 61010-031;
c) the information on markings was extended;
d) the information on the operating instructions was extended;
---------------------- Page: 5 ----------------------
– 4 – IEC 61557-7:2019 © IEC 2019
e) complement to the information on the testing of leads;
f) test leads for insulated conductors were introduced;
g) Annex B was added with information on phase sequence tests and indications.
The text of this International Standard is based on the following documents:
FDIS Report on voting
85/683/FDIS 85/698/RVD

Full information on the voting for the approval of this International Standard can be found in

the report on voting indicated in the above table.

This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

This International Standard is to be used in conjunction with IEC 61557-1:2019.

A list of all parts of the IEC 61557 series, published under the general title 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, can be found on the IEC website

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates that it

contains colours which are considered to be useful for the correct understanding of its

contents. Users should therefore print this document using a colour printer.
---------------------- Page: 6 ----------------------
IEC 61557-7:2019 © IEC 2019 – 5 –
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 –
Part 7: Phase sequence
1 Scope

This part of IEC 61557 specifies the requirements applicable to measuring equipment for

testing the phase sequence in three-phase distribution systems. Indication of the phase

sequence can be mechanical, visual and/or audible.

This document does not apply to additional measurements for other quantities. It does not

apply to monitoring relays.

NOTE Common worldwide three-phase distribution systems are depicted in IEC 61010-1.

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.

IEC 61010-1:2010, Safety requirements for electrical equipment for measurement, control,

and laboratory use – Part 1: General requirements
IEC 61010-1:2010/AMD1:2016

IEC 61010-2-030:2017, Safety requirements for electrical equipment for measurement, control,

and laboratory use – Part 2-030: Particular requirements for equipment having testing or

measuring circuits

IEC 61010-031, Safety requirements for electrical equipment for measurement, control and

laboratory use – Part 031: Safety requirements for hand-held and hand-manipulated

assemblies for electrical test and measurement

IEC 61557-1:2019 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 – Part 1:

General requirements
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 61557-1 and the

following apply.

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

addresses:
——————

A consolidated version of this publication exists, comprising IEC 61010-1:2010 and

IEC 61010-1:2010/AMD1:2016.
---------------------- Page: 7 ----------------------
– 6 – IEC 61557-7:2019 © IEC 2019
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
phase sequence indicator

instrument intended to indicate, in a polyphase system, the sequence in which the

instantaneous voltages of the phase conductors reach their maximum values
[SOURCE: IEC 60050-313:2001, 313-01-21]
3.2
phase sequence indication
information displayed by a phase sequence indicator
3.3
phase sequence test

test taken to determine that the phase sequence of a polyphase winding is correct

[SOURCE: IEC 60050-411:1996, 411-53-45]
4 Requirements
4.1 General

In addition to the requirements of IEC 61557-1:2019, Clause 4, the requirements of Clause 4

of this document shall apply.
4.2 Indication

All indications shall be unambiguously displayed on the phase sequence indicator when the

input to the phase indicator is between 85 % and 110 % of the nominal system voltage and

between 95 % and 105 % of the nominal system frequency.

Indications shall also be unambiguously detectable in the presence of visual or audible

interference.

The phase sequence indicator shall display a valid phase sequence indication, positive or

negative, if the values of the voltage to earth of the three phases are within the voltage range

specified above and the phase delay between two consecutive phases is 120°.

The phase sequence indicator shall not display a valid phase sequence indication, positive or

negative, if the three-phase distribution system is heavily unbalanced.

NOTE An unbalanced system could be due to unbalanced loads on the three phases or due to cabling errors.

In particular the measuring equipment shall not display a valid phase sequence indication in

the following cases:
1) one or more of the phase conductors are open-circuit;

2) one or more of the phase conductors are connected to neutral or protective earth;

3) two conductors are connected to the same phase.

The specific indications displayed in the above error cases shall be mentioned in the

operating instructions of the phase sequence indicator.

The limits of unbalance in amplitude and in phase delay that the phase sequence indicator

can handle reliably shall also be mentioned in the operating instructions.
---------------------- Page: 8 ----------------------
IEC 61557-7:2019 © IEC 2019 – 7 –
4.3 Measuring equipment
4.3.1 General

The measuring equipment for the phase sequence test is intended for temporary operation,

but shall withstand continuous operation.

Equipment intended to be used on the distribution system shall be rated at least for

measurement category III according to IEC 61010-2-030.

Equipment intended to be used on socket outlets only can be rated for measurement category

II according to IEC 61010-2-030.

The measuring equipment shall not be damaged nor shall the user be exposed to danger

when the measuring equipment is connected to 120 % of the rated system voltage or to 120 %

of the maximum voltage of its rated voltage range.

The phase sequence test (see Annex B) can be realised with test probes for direct contact

with live parts, conductors or terminals, or with test clamps for inductive detection on

insulated conductors.
4.3.2 Portable phase sequence indicator

Portable phase sequence indicators shall be housed in an enclosure of insulating material and

comply with the requirements for double insulation or reinforced insulation (protection class II).

Portable phase sequence indicators shall be designed in such a manner that when either one

or two measuring leads are connected to earth and the remaining measuring leads are

connected to their corresponding phase conductors, the resulting total current to earth should

not exceed 3,5 mA RMS. The phase conductors shall be at 110 % of the maximum rated

voltage for which the equipment is designed.
4.3.3 Test leads for direct contact with live parts and accessories

Phase sequence indicators designed for direct contact to live parts shall be provided with

permanently connected test leads or with terminals for removable test leads complying with

IEC 61010-031.
The following applies to leads.

Test probes, test leads, clips and other accessories used with phase sequence indicators

shall be in accordance with the requirements of IEC 61010-031.

A test lead cable that has a wear indicator shall, at the minimum, provide double insulation or

reinforced insulation when new and, at the minimum, basic insulation when the wear indicator

is reached (see IEC 61010-031).

Portable measuring equipment, together with its test leads, shall comply with the

requirements for mechanical strength according to IEC 61010-1 and in addition shall be tested

in accordance with 6.4.

These requirements do not apply when the phase sequence indicator forms part of a

multi-purpose instrument with provisions for carrying.
---------------------- Page: 9 ----------------------
– 8 – IEC 61557-7:2019 © IEC 2019
5 Marking and operating instructions
5.1 Marking

In addition to IEC 61557-1:2019, 5.1 and 5.2, the following information shall be provided on

the measuring equipment:

– symbol for double insulation in accordance with IEC 61010-1:2010, Table 1, symbol 11;

– designation of leads L1, L2 and L3 on the equipment and on the leads;

– the measurement category shall be printed on the equipment close to the test lead

connection.
5.2 Operating instructions
IEC 61557-1:2019, 5.3 applies.
6 Tests
6.1 General
6.1.1 Tests – General

In addition to the tests of IEC 61557-1:2019, Clause 6, the following tests shall be performed.

6.1.2 Visual display
Tests of the visual display are performed under the following conditions.

The display shall be unambiguously discernible by a person with 6/6 vision from a distance of

500 mm at ambient lighting levels from 30 lx to 1 000 lx. During the measurement, the

measuring equipment shall be placed on a matt grey surface (type test).

A visual comparison under reference conditions with equipment that has successfully passed

the type test is adequate for a routine test with respect to the visual display. The display on

the item under test shall produce a similar or better readability (routine tests).

6.1.3 Audible indication (if applicable)

The test for the audible indication is performed at a sound level of L = 75 dB (white noise).

The indication shall generate a sound between 1 kHz and 4 kHz and be unambiguously

discernible by a person with a hearing loss of less than 15 dB HL under these conditions

(routine test).
6.2 Leakage current
The requirements under 4.3.2 shall be tested as follows.

The phase sequence indicator shall be connected in series with a current measuring

instrument that has one lead connected with earth, and with the other interconnected leads

connected with a phase conductor at a voltage of 110 % of its rated voltage or a voltage at

the upper limit of its rated voltage range. The magnitude of the current shall not exceed the

value specified under 4.3.2.
This test shall be executed on each conductor (routine test).
---------------------- Page: 10 ----------------------
IEC 61557-7:2019 © IEC 2019 – 9 –
6.3 Test of mechanical requirements (type tests)
6.3.1 Mechanical shock test

For the purpose of a mechanical shock test, the item under test shall be suspended as shown

in Annex A, Figure A.1, using a pendulum length of 2 m. The item under test shall be dropped

in a pendulum movement with a deflection of 1 m in height to hit a hard wooden plate 50 mm

thick. The test shall be carried out so that each of the sides of the enclosure parallel to the

suspension hits the wood once.
6.3.2 Test of leads for direct contact with live parts

The strain relief of permanently attached leads shall be tested by a drop test in accordance

with Annex A, Figure A.2, in the following manner:

– the item under test shall be suspended so that it is caught with the extended lead after a

free drop of 2 m;

– the item under test shall be dropped three times from the suspension point for each of the

leads;
– the enclosure of the measuring equipment shall be free from damage;
– permanently attached leads shall not have become detached from the measuring
equipment;

– live parts of the leads connected by means of plugs shall remain inaccessible when they

have become unplugged from the measuring equipment;
– no parts inside the measuring equipment shall have become loose.
6.4 Overvoltage
The applicable requirement of 4.3.1 shall be tested as follows:

Compliance with the requirements given in 4.3.1 shall be tested by connecting, for a duration

of at least 10 min, the item under test to a three-phase system at 120 % of the rated system

voltage or, in the case of multi-range measuring equipment, at 120 % of all rated voltages

(type test).

The surface temperature of EUT shall be measured and checked according to IEC 61010-1.

Compliance with the requirements given in 4.3 shall be tested by operating the item under test

for a duration of at least 1 h at the rated voltage or, in the case of multi-range measuring

equipment, at all rated voltage values (type test).
6.5 Test of markings

The markings shall be checked in respect of legibility by a visual inspection (type test).

---------------------- Page: 11 ----------------------
– 10 – IEC 61557-7:2019 © IEC 2019
Annex A
(normative)
Illustrations for mechanical tests
Mechanical shock tests shall be performed according to Figure A.1.
Dimensions in metres
Figure A.1 – Mechanical shock test
---------------------- Page: 12 ----------------------
IEC 61557-7:2019 © IEC 2019 – 11 –
Drop tests shall be performed according to Figure A.2.
Dimensions in metres
Key
a original lead A initial position where the equipment is held
b joint B end position after the release of the equipment
c extension to 2 m
Figure A.2 – Drop test
---------------------- Page: 13 ----------------------
– 12 – IEC 61557-7:2019 © IEC 2019
Annex B
(informative)
Phase sequence test
B.1 Phase sequence test – Tripolar connection

The measuring equipment for the phase sequence test with tripolar connection is connected

to the three-phase distribution system using three separate test probes marked L1, L2 and L3

(see 5.1).

Each test probe is connected to the conductor or terminal foreseen to be at the corresponding

phase L1, L2 or L3 of the distribution system.
Figure B.1 – Tripolar connection

The phase sequence indication is positive, commonly called "clockwise" (CW) or "right" (R), if

the three phases are in the foreseen phase sequence.

The phase sequence indication is negative, commonly called "counter-clockwise" (CCW) or

"left" (L), if the three phases are in a sequence different than foreseen: two of the three phase

connections are crossed.
NOTE New phase sequence tests carried out after crossing tests probes L
...

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