General safety requirements for residual current operated protective devices

IEC 60775:2017(E) provides general minimum requirements, recommendations and information for the drafting of standards on residual current operated protective devices (hereinafter referred to as residual current devices, "RCDs"). It applies to any device providing residual current protection intended primarily for protection against electric shock hazard.
This first edition cancels and replaces IEC TR 60755 published in 2008 and constitutes a technical revision.
This edition includes the following significant technical changes with respect to IEC TR 60755:
a. restructuration of the document, as a Group Safety Publication, in compliance with Guide 104;
b. introduction of classification for type F RCDs;
c. introduction of Clause 9 for tests of RCDs (operating characteristics, electrical endurance, behaviour in short-circuit conditions, trip-free mechanism, test device, surges, reliability, EMC).
It has the status of a group safety publication in accordance with IEC Guide 104.

General Information

Status
Published
Publication Date
25-Oct-2017
Current Stage
PPUB - Publication issued
Start Date
26-Oct-2017
Completion Date
26-Oct-2017
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IEC 60755
Edition 1.0 2017-10
INTERNATIONAL
STANDARD
GROUP SAFETY PUBLICATION
General safety requirements for residual current operated protective devices
IEC 60755:2017-10(en)
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IEC 60755
Edition 1.0 2017-10
INTERNATIONAL
STANDARD
GROUP SAFETY PUBLICATION
General safety requirements for residual current operated protective devices
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.120.50 ISBN 978-2-8322-4935-2

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

® Registered trademark of the International Electrotechnical Commission
---------------------- Page: 3 ----------------------
– 2 – IEC 60755:2017 © IEC 2017
CONTENTS

FOREWORD ........................................................................................................................... 7

INTRODUCTION ..................................................................................................................... 9

1 Scope ............................................................................................................................ 10

2 Normative references .................................................................................................... 10

3 Terms and definitions .................................................................................................... 11

4 Classification ................................................................................................................. 12

4.1 According to the method of operation .................................................................... 12

4.2 According to the type of installation ...................................................................... 12

4.3 According to the possibility of adjusting the residual operating current .................. 12

4.4 According to their operating characteristics and behaviour in presence of DC

components .......................................................................................................... 12

4.5 According to time-delay (in presence of a residual current) ................................... 12

4.6 According to the protection against external influences ......................................... 12

4.7 According to the method of mounting .................................................................... 12

4.8 According to the method of connection ................................................................. 13

4.9 According to the type of terminals ......................................................................... 13

4.10 According to the number of poles and current paths .............................................. 13

4.11 According to the instantaneous tripping current ..................................................... 13

4.12 According to the I t characteristics ....................................................................... 14

4.13 According to overcurrent protection ....................................................................... 14

4.14 According to the method of construction ............................................................... 14

4.15 According to the intended use ............................................................................... 14

4.16 According to the range of ambient air temperature ................................................ 15

5 Characteristics of residual current devices ..................................................................... 15

5.1 Summary of characteristics ................................................................................... 15

5.2 Rated quantities and other characteristics ............................................................. 15

5.2.1 Rated voltages .............................................................................................. 15

5.2.2 Rated current (I ) .......................................................................................... 16

5.2.3 Rated frequency ............................................................................................ 16

5.2.4 Rated making and breaking capacity (I ) ...................................................... 16

5.2.5 Rated residual operating current (I ) ........................................................... 16

5.2.6 Rated residual non-operating current (I ) .................................................. 16

Δno

5.2.7 Rated residual making and breaking capacity (I ) ...................................... 16

5.2.8 Rated conditional short-circuit current ............................................................ 16

5.2.9 Rated conditional residual short-circuit current (I∆ ) ...................................... 16

5.2.10 Operating characteristics in case of residual currents with DC

components ................................................................................................... 17

5.3 Standard and preferred values .............................................................................. 18

5.3.1 Values of rated operational voltage (U ) ........................................................ 18

5.3.2 Values of rated current (I ) ............................................................................ 18

5.3.3 Standard values of rated residual operating current (I ) .............................. 18

5.3.4 Standard value of residual non-operating current (I ) ................................ 18

∆no

5.3.5 Preferred values of rated frequency ............................................................... 18

5.3.6 Standard values of rated impulse withstand voltage (U ) ........................... 18

imp

5.3.7 Standard values of operating time ................................................................. 18

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IEC 60755:2017 © IEC 2017 – 3 –
5.3.8 Standard minimum value of non-operating overcurrent in case of a load

through an RCD with two current paths .......................................................... 19

5.3.9 Standard minimum value of non-operating overcurrent in case of a
single-phase load through a three- or four-pole or four-current-paths

RCD .............................................................................................................. 19

5.3.10 Minimum value of the rated making and breaking capacity (I ) ..................... 19

5.3.11 Minimum value of the rated residual making and breaking capacity

(I∆ ) ............................................................................................................. 19

5.3.12 Preferred values of the rated conditional short-circuit current ........................ 19

5.3.13 Preferred values of the rated conditional residual short-circuit current

(I∆ ) .............................................................................................................. 19

5.4 Coordination with short-circuit protective devices (SCPDs) ................................... 19

6 Marking and other product information ........................................................................... 20

6.1 Information and marking for RCDs according to 4.15.1 ......................................... 20

6.2 Information and marking for RCDs according to 4.15.2 and 4.15.3 ........................ 21

7 Conditions for operation in service and for installation ................................................... 22

7.1 Preferred ranges of application, reference values of influencing

quantities/factors and the associated test tolerances ............................................ 22

7.2 Conditions of installation ....................................................................................... 22

7.3 Pollution degree .................................................................................................... 22

7.4 Additional standard conditions for operation in service and for installation

when an RCD is incorporated or embedded in an equipment................................. 22

8 Requirements for construction and operation ................................................................. 22

8.1 Mechanical design ................................................................................................ 22

8.1.1 General ......................................................................................................... 22

8.1.2 Mechanism .................................................................................................... 24

8.1.3 Clearance and creepage distances ................................................................ 25

8.1.4 Screws, current-carrying parts and connections ............................................. 25

8.1.5 Terminals for external conductors .................................................................. 26

8.2 Protection against electric shock ........................................................................... 26

8.3 Dielectric properties and isolating capability .......................................................... 26

8.4 Temperature rise .................................................................................................. 27

8.5 Operating characteristics ...................................................................................... 27

8.5.1 General ......................................................................................................... 27

8.5.2 Operation in response to the type of residual current ..................................... 27

8.5.3 Operation in presence of a residual current equal to and greater than

I∆ ................................................................................................................ 28

8.5.4 Additional requirements for RCDs according to 4.15.2 and 4.15.3 .................. 29

8.6 Mechanical and electrical endurance .................................................................... 29

8.7 Performance at short-circuit currents .................................................................... 29

8.8 Resistance to mechanical shock and impact ......................................................... 29

8.9 Resistance to heat ................................................................................................ 29

8.10 Resistance to abnormal heat and to fire ................................................................ 29

8.11 Test device ........................................................................................................... 30

8.12 Requirements for RCDs in case of loss of supply .................................................. 30

8.13 Behaviour of RCDs in case of overcurrent in the main circuit ................................ 30

8.14 Behaviour of RCDs in case of current surges caused by impulse voltages ............ 30

8.15 Void ...................................................................................................................... 30

8.16 Reliability .............................................................................................................. 30

8.17 Electromagnetic compatibility (EMC) ..................................................................... 31

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– 4 – IEC 60755:2017 © IEC 2017

8.18 Resistance to temporary overvoltages (TOV) ........................................................ 31

9 Preparation of test clauses for RCD product standards and of test clauses for

RCD incorporated or embedded in an equipment ........................................................... 31

9.1 General ................................................................................................................. 31

9.1.1 General test conditions .................................................................................. 31

9.1.2 Additional test conditions for preparation of standards for RCDs

according to 4.15.2 ........................................................................................ 32

9.1.3 Additional test conditions for preparation of standards for RCDs

according to 4.15.3 ........................................................................................ 32

9.1.4 Tests not specified in this document .............................................................. 32

9.2 Operating characteristics ...................................................................................... 32

9.2.1 General requirements for operating characteristics tests ................................ 32

9.2.2 Tests of RCDs of type AC .............................................................................. 33

9.2.3 Tests of RCDs of type A ................................................................................ 33

9.2.4 Tests of RCD of type F .................................................................................. 34

9.2.5 Tests of RCDs of type B ................................................................................ 35

9.3 Tests of electrical endurance ................................................................................ 37

9.4 Tests of behaviour of the RCD under short-circuit conditions ................................ 37

9.4.1 General ......................................................................................................... 37

9.4.2 Short-circuit tests .......................................................................................... 38

9.4.3 Behaviour of the RCD during and after the tests ............................................ 39

9.5 Test of the trip-free mechanism ............................................................................. 39

9.6 Verification of the operation of the test device ....................................................... 40

9.7 Tests of behaviour of RCDs in case of current surges caused by impulse

voltages ................................................................................................................ 40

9.7.1 Current surge test for all RCDs (0,5 µs/100 kHz ring wave test) ..................... 40

9.7.2 Verification of behaviour at surge currents (8/20 µs surge current test) .......... 40

9.8 Tests of reliability .................................................................................................. 41

9.8.1 Climatic test................................................................................................... 41

9.8.2 Test with temperature of 40 °C ...................................................................... 41

9.8.3 Verification of the resistance to ageing .......................................................... 42

9.9 Tests of electromagnetic compatibility (EMC) ........................................................ 42

9.9.1 General ......................................................................................................... 42

9.9.2 Specific requirements for RCDs for household and similar uses ..................... 43

Annex A (informative) Recommended diagram for short-circuit tests ................................... 54

Annex B (informative) Possible load and fault currents ....................................................... 57

Annex C (informative) Correspondence between clauses and modules ............................... 60

Annex D (informative) Relationship with product standards .................................................. 62

D.1 General ................................................................................................................. 62

D.2 RCD product standards ......................................................................................... 62

D.3 Application of RCDs .............................................................................................. 62

Bibliography .......................................................................................................................... 64

Figure 1 – Void ..................................................................................................................... 52

Figure 2 – Void ..................................................................................................................... 52

Figure 3 – Void ..................................................................................................................... 52

Figure 4 – Void ..................................................................................................................... 52

Figure 5 – Void ..................................................................................................................... 52

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IEC 60755:2017 © IEC 2017 – 5 –

Figure 6 – Void ..................................................................................................................... 52

Figure 7 – Void ..................................................................................................................... 52

Figure 8 – Void ..................................................................................................................... 52

Figure 9 – Void ..................................................................................................................... 52

Figure 10 – Void ................................................................................................................... 52

Figure 11 – Void ................................................................................................................... 52

Figure 12 – Void ................................................................................................................... 52

Figure 13 – Void ................................................................................................................... 52

Figure 14 – Void ................................................................................................................... 52

Figure 15 – Void ................................................................................................................... 53

Figure 16 – Current ring wave 0,5 µs/100 kHz ...................................................................... 53

Figure A.1 – Diagram for all the short-circuit tests................................................................. 55

Figure A.2 – Detail of impedance Z or Z .............................................................................. 56

Figure B.1 – Possible fault currents in systems with semiconductors .................................... 59

Table 1 – Values of influencing quantities ............................................................................. 43

Table 2 – Marking for RCDs according to 4.15.1 ................................................................... 44

Table 3 – Marking for RCDs according to 4.15.2 and 4.15.3 .................................................. 46

Table 4 – Standard values of maximum break time of non time-delay type RCDs for

AC residual current ............................................................................................................... 46

Table 5 – Standard values of maximum break time of non time-delay type RCDs for

half-wave pulsating DC residual current ................................................................................ 47

Table 6 – Standard values of maximum break time of non time-delay type RCDs for

residual direct currents which result from rectifying circuits and/or smooth DC residual

current .................................................................................................................................. 47

Table 7 – Acceptable alternative standard values of maximum break times for RCDs

with a rated residual current of 6 mA and non time-delay type intended to be used in

bi-phase system 120 V with middle point .............................................................................. 47

Table 8 – Standard values of break time for AC residual current for time-delay type

residual current devices ........................................................................................................ 47

Table 9 – Standard values of break time for pulsating DC residual current for time-

delay type residual current devices ....................................................................................... 48

Table 10 – Standard values of break time for rectifying circuits and smooth DC

residual current for time-delay type residual current devices ................................................. 48

Table 11 – Void .................................................................................................................... 48

Table 12 – Void .................................................................................................................... 48

Table 13 – Tripping current limits .......................................................................................... 48

Table 14 – Tripping current limits .......................................................................................... 49

Table 15 – Different frequency component values of test currents and starting current

values (I ) for verifying the operating in case of steady increased residual current .............. 49

Table 16 – Operating current ranges for composite residual current ...................................... 49

Table 17 – Tripping current ranges for type B RCDs at frequencies which differ from

the rated frequency 50/60 Hz ................................................................................................ 49

Table 18 – Tripping current limits .......................................................................................... 50

Table 19 – Void .................................................................................................................... 50

Table 20 – Void .................................................................................................................... 50

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– 6 – IEC 60755:2017 © IEC 2017

Table 21 – Void .................................................................................................................... 50

Table 22 – Void .................................................................................................................... 50

Table 23 – Void .................................................................................................................... 50

Table 24 – Void .................................................................................................................... 50

Table 25 – Void .................................................................................................................... 50

Table 26 – Void .................................................................................................................... 50

Table 27 – Void .................................................................................................................... 50

Table 28 – Void .................................................................................................................... 50

Table 29 – Void .................................................................................................................... 50

Table 30 – Withstand values and duration of temporary overvoltages ................................... 50

Table 31 – Void .................................................................................................................... 50

Table 32 – Void .................................................................................................................... 50

Table 33 – Void .................................................................................................................... 50

Table 34 – Void .................................................................................................................... 51

Table 35 – Void .................................................................................................................... 51

Table 36 – Minimum values of I t and I .............................................................................. 51

Table 37 – Void .................................................................................................................... 51

Table 38 – Void .................................................................................................................... 51

Table 39 – Void .................................................................................................................... 51

Table 40 – Void .................................................................................................................... 51

Table 41 – Void .................................................................................................................... 51

Table 42 – Void .................................................................................................................... 51

Table 43 – Void .................................................................................................................... 51

Table 44 – Void .................................................................................................................... 51

Table 45 – List of electromagnetic phenomena covered by IEC 61543 .................................. 52

Table C.1 – Correspondence between clauses and modules used in this standard .............. 60

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IEC 60755:2017 © IEC 2017 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
GENERAL SAFETY REQUIREMENTS FOR RESIDUAL CURRENT
OPERATED PROTECTIVE DEVICES
FOREWORD

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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an internatio

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