IEC TS 63053:2017

General requirements for residual current operated protective devices for DC system

IEC TS 63053:2017(E) provides general minimum requirements, recommendations and information for the drafting and testing procedures of standards for residual current operated protective devices, intended to be used in DC systems having a rated voltage not exceeding 400 V DC and a rated current not exceeding 125 A, hereafter referred to as DC-RCDs.

General Information

• Status: Published
• Publication Date: 28-Jun-2017
• ICS: 29.120.50 - Fuses and other overcurrent protection devices
• Technical Committee: SC 23E - Circuit-breakers and similar equipment for household use
• Drafting Committee: WG 2 - TC 23/SC 23E/WG 2
• Current Stage: PPUB - Publication issued
• Start Date: 29-Jun-2017
• Completion Date: 03-Aug-2017

Overview

IEC TS 63053:2017 is a Technical Specification that defines general minimum requirements, recommendations and testing guidance for residual current operated protective devices (DC‑RCDs) intended for use in DC systems with a rated voltage up to 400 V DC and a rated current up to 125 A. The document is aimed at helping national and product standards drafters and test laboratories to specify and verify safe, reliable DC‑RCD operation in photovoltaic, industrial and battery‑based DC installations.

Key topics and technical requirements

The specification covers the full lifecycle of DC‑RCD standardization and testing, including:

• Scope and classification: device types based on installation, adjustable residual operating current, time‑delay behavior, mounting and terminal types, number of poles, instantaneous tripping and I²t characteristics.
• Rated quantities and characteristics: rated voltages, rated direct current, making/breaking capacities, residual operating and non‑operating currents, conditional short‑circuit currents and preferred/standard values.
• Construction and safety: mechanical design, clearance/creepage, terminals, protection against electric shock, dielectric strength and temperature‑rise limits.
• Operating performance: defined trip behavior for steady, sudden and high residual currents (including tests for I∆n and I∆no), time‑delay categories, and coordination with short‑circuit protective devices (SCPDs).
• Robustness and EMC: mechanical/electrical endurance, short‑circuit performance, resistance to shock, heat, fire, and electromagnetic compatibility (including ripple immunity). Specific surge tests include the 0.5 μs/100 kHz ring‑wave test and 8/20 μs surge current tests.
• Test program and preparation: recommended test circuits, short‑circuit and inrush current tests, verification of trip‑free mechanisms, ageing of electronic components and climatic/reliability tests (e.g., tests at 40 °C).

Practical applications and users

IEC TS 63053 is practical for anyone involved in the design, manufacture, testing, certification or regulation of DC safety systems, including:

• Manufacturers of DC‑RCDs and DC switchgear
• Test laboratories and certification bodies preparing product standards and type‑approval tests
• System integrators and designers of photovoltaic (PV), energy storage and electric vehicle charging installations
• Regulatory bodies and standards committees drafting national or product standards for DC protective devices

By using IEC TS 63053, stakeholders can ensure consistent safety performance, interoperability and clearer requirements for DC residual current protection.

Related standards

• IEC TS 63053 cross‑references general IEC publications and EMC guidance (e.g., IEC 61543) and should be used alongside applicable product and installation standards for DC systems.

Standards Content (Sample)

IEC TS 63053 ®
Edition 1.0 2017-06
TECHNICAL
SPECIFICATION
General requirements for residual current operated protective devices
for DC systems
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Central Office Tel.: [phone]
3, rue de Varembé Fax: [phone]
CH-1211 Geneva 20 [e-mail]
Switzerland www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing 20 000 terms and definitions in
Technical Specifications, Technical Reports and other English and French, with equivalent terms in 16 additional
documents. Available for PC, Mac OS, Android Tablets and languages. Also known as the International Electrotechnical
iPad. Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a 65 000 electrotechnical terminology entries in English and
variety of criteria (reference number, text, technical French extracted from the Terms and Definitions clause of
committee,…). It also gives information on projects, replaced IEC publications issued since 2002. Some entries have been
and withdrawn publications. collected from earlier publications of IEC TC 37, 77, 86 and

CISPR.
IEC Just Published - webstore.iec.ch/justpublished

Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: [e-mail].
IEC TS 63053 ®
Edition 1.0 2017-06
TECHNICAL
SPECIFICATION
General requirements for residual current operated protective devices

for DC systems
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.120.50 ISBN 978-2-8322-4526-2

– 2 – IEC TS 63053:2017 © IEC 2017
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 9
3 Terms and definitions . 10
4 Classification . 11
4.1 According to the type of installation . 11
4.2 According to the possibility of adjusting the residual operating current . 11
4.3 According to time-delay (in presence of a residual current) . 11
4.4 According to the protection against external influences . 12
4.5 According to the method of mounting . 12
4.6 According to the method of connection . 12
4.7 According to the type of terminals . 12
4.8 According to the number of poles and current paths . 12
4.9 According to the instantaneous tripping current . 13
4.10 According to the I²t characteristics . 13
4.11 According to overcurrent protection . 13
4.12 According to the method of construction . 13
4.13 According to the range of ambient air temperature . 13
4.14 According to the time constant . 13
4.15 According to the current direction through the poles. 13
5 Characteristics of residual current devices . 14
5.1 Summary of characteristics . 14
5.2 Rated quantities and other characteristics . 14
5.2.1 Rated voltages . 14
5.2.2 Rated direct current (I ) . 14
n
5.2.3 Rated making and breaking capacity (I ) . 14
m
5.2.4 Rated residual operating direct current (I ) . 15
∆n
5.2.5 Rated residual non-operating direct current (I ) . 15
∆no
5.2.6 Rated residual direct making and breaking capacity (I ) . 15
∆m
5.2.7 Rated conditional direct short-circuit current (I ) . 15
nc
5.2.8 Rated conditional residual direct short-circuit current (I ) . 15
∆c
5.2.9 Time-delay DC-RCD . 15
5.2.10 Operating characteristics . 15
5.3 Standard and preferred values . 15
5.3.1 Preferred values of rated operational voltage (U ) . 15
e
5.3.2 Preferred values of rated current (I ) . 16
n
5.3.3 Standard values of rated residual operating direct current (I ) . 16
∆n
5.3.4 Standard value of residual non-operating direct current (I ) . 16
∆no
5.3.5 Standard values of rated impulse withstand voltage (U ) . 16
imp
5.3.6 Standard values of operating time . 17
5.3.7 Minimum value of the rated making and breaking capacity (I ) . 18
m
5.3.8 Minimum value of the rated residual direct making and breaking
capacity (I ) . 18
∆m
5.4 Coordination with short-circuit protective devices (SCPDs) . 18
5.4.1 General . 18
5.4.2 Preferred values of the rated conditional direct short-circuit current (I ). 18
nc
5.4.3 Preferred values of the rated conditional residual direct short-circuit
current (I ) . 18
∆c
6 Marking and other product information . 19
7 Conditions for operation in service and for installation . 20
7.1 Preferred ranges of application, reference values of influencing
quantities/factors and associated test tolerances . 20
7.2 Conditions of installation . 21
7.3 Pollution degree . 21
8 Requirements for construction and operation . 21
8.1 Mechanical design . 21
8.1.1 General . 21
8.1.2 Mechanism . 22
8.1.3 Clearance and creepage distances . 23
8.1.4 Screws, current-carrying parts and connections . 23
8.1.5 Terminals for external conductors . 24
8.2 Protection against electric shock . 24
8.3 Dielectric properties and isolating capability . 24
8.4 Temperature-rise . 24
8.5 Operating characteristics . 25
8.5.1 General . 25
8.5.2 Operation in response to a residual current equal to and greater than
I . 25
∆n
8.5.3 Operation in response time in presence of a residual current equal to
and greater than I . 25
∆n
8.6 Mechanical and electrical endurance . 25
8.7 Performance at short-circuit currents . 25
8.8 Resistance to mechanical shock and impact . 26
8.9 Resistance to heat . 26
8.10 Resistance to abnormal heat and to fire . 26
8.11 Test device . 26
8.12 Requirements for DC-RCDs in case of loss of supply . 26
8.13 Behaviour of DC-RCDs in case of overcurrent in the main circuit . 27
8.14 Behaviour of DC-RCDs in the case of current surges caused by impulse
voltages . 27
8.15 Void . 27
8.16 Reliability . 27
8.17 Electromagnetic compatibility (EMC) . 27
8.18 Resistance to temporary overvoltages (TOVs) . 27
8.19 Performance of DC-RCDs at inrush currents . 28
9 Preparation of test clauses for DC-RCDs product standard . 28
9.1 General . 28
9.1.1 General test conditions . 28
9.1.2 Test clauses not specified in this document . 28
9.2 Operating characteristics . 29
9.2.1 General requirements for operating characteristics tests . 29
9.2.2 Steady increase of residual current . 29
9.2.3 Closing on a residual current . 29
9.2.4 Sudden appearance of residual current . 29
9.2.5 Residual current higher than 3 I . 29
∆n
– 4 – IEC TS 63053:2017 © IEC 2017
9.2.6 Tests with load . 29
9.2.7 Tests at the temperature limits . 29
9.2.8 Additional test for delay type RCDs . 30
9.3 Tests of electrical endurance . 30
9.4 Tests of behaviour of the DC-RCD under short-circuit conditions . 30
9.4.1 General . 30
9.4.2 Short-circuit tests . 30
9.4.3 Behaviour of the DC-RCD during and after the tests . 32
9.5 Test of the trip-free mechanism . 33
9.6 Verification of the operation of the test device . 33
9.7 Test of behaviour of DC-RCDs in case of current surges caused by impulse
voltages . 33
9.7.1 Current surge test for all DC-RCDs (0,5 μs/100 kHz ring wave test) . 33
9.7.2 Verification of behaviour with surge currents (8/20 μs surge current test) . 33
9.8 Tests of reliability . 34
9.8.1 Climatic test. 34
9.8.2 Test with temperature of 40 °C . 34
9.9 Verification of ageing of electronic components . 35
9.10 Tests of electromagnetic compatibility (EMC) . 35
9.10.1 General . 35
9.10.2 General requirements . 36
9.10.3 Specific requirements on ripple immunity . 38
9.10.4 Verification of behaviour during inrush currents . 38
Annex A (informative) Recommended diagram for short-circuit tests . 42
Bibliography . 45

Figure 1 – Damped oscillator current wave 0,5 µs/100 kHz . 39
Figure 2 – Examples of installation . 40
Figure 3 – Downstream circuit for simulating inrush currents. 41
Figure 4 – Example of test circuit for verification of ageing of electronic components . 41
Figure A.1 – Diagram for all the short-circuit tests. 43
Figure A.2 – Detail of impedance Z or Z . 44
Table 1 – Preferred values of rated operational voltage (U ). 16
e
Table 2 – Standard values of maximum break time for non-time-delay DC-RCDs . 17
Table 3 – Standard values of break time and non-actuating time for time-delay DC-
RCDs . 17
Table 4 – Marking for DC-RCDs . 19
Table 5 – Values of influencing quantities . 21
Table 6 – Tripping current limits . 25
Table 7 – Withstand values and duration of temporary overvoltages . 27
Table 8 – List of electromagnetic phenomena covered by IEC 61543 . 37

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
GENERAL REQUIREMENTS FOR RESIDUAL CURRENT OPERATED
PROTECTIVE DEVICES FOR DC SYSTEMS

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as "IEC
Publication(s)"). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
The main task of IEC technical committees is to prepare International Standards. In
exceptional circumstances, a technical committee may propose the publication of a technical
specification when
• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
Technical specifications are subject to review within three years of publication to decide
whether they can be transformed into International Standards.
IEC TS 63053, which is a technical specification, has been prepared by subcommittee 23E:
Circuit-breakers and similar equipment for household use, of IEC technical committee 23:
Electrical accessories.
– 6 – IEC TS 63053:2017 © IEC 2017
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
23E/1006/DTS 23E/1021/RVDTS
Full information on the voting for the approval of this technical specification 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.
In this standard, the following print types are used:
– conformity statements: in italic type
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• transformed into an International standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

INTRODUCTION
In AC systems, residual current devices are used to provide protection against the risk of
electric shocks. In IEC 60364 (all parts), residual current devices are used for automatic
disconnection of supply in case of fault (see Clause 411 of IEC 60364-4-41:2005) and
residual current devices with rated residual operating current not exceeding 30 mA are used
as additional protection (see 415 of IEC 60364-4-41:2005). IEC SC 23E has developed a set
of standards for residual current operated protective devices intended to be used in AC
systems.
DC systems are used for applications such as photovoltaic installations, data centres and
telecom centres, and electric vehicle charging systems. In addition, standards for plugs and
socket-outlets for ICT equipment installed in date centres and telecom centre have been
published. Therefore, a reference document for residual current devices intended to be used
in DC supply systems is necessary.
Residual current devices for DC systems may be used to provide fault protection (automatic
disconnection of supply according to Clause 411 of IEC 60364-4-41:2005); they may also be
used to provide protection against direct contact. They provide protection against electric
shock downstream of the device in DC networks.
This document defines the operating characteristics for residual current operated protective
devices for DC systems. Details of how they should be installed to provide the desired level of
protection are specified in the various parts of the IEC 60364 series.
The operating characteristics given in this document are based on the information contained
in IEC 60479 (all parts) and the requirements in IEC 60364-4-41.
This document is intended for use by technical committees in the preparation of standards for
residual current devices. It is not intended to be used as a stand-alone document, for
example, for certification.
– 8 – IEC TS 63053:2017 © IEC 2017
GENERAL REQUIREMENTS FOR RESIDUAL CURRENT OPERATED
PROTECTIVE DEVICES FOR DC SYSTEMS

1 Scope
This document provides general minimum requirements, recommendations and information for
the drafting and testing procedures of standards for residual current operated protective
devices, intended to be used in DC systems having a rated voltage not exceeding 400 V DC
and a rated current not exceeding 125 A, hereafter referred to as DC-RCDs.
NOTE 1 This document can also be used as a guide for DC-RCDs with voltages up to 1 500 V DC.
This document is primarily intended to be used as a reference for drafting product safety
standard for DC-RCDs.
This document cannot be used alone but is intended for use by technical committees in the
preparation of standards for products similar to those mentioned in the scope of this standard.
This document applies to a device
– which detects a residual current,
– compares it to a reference value, and
– opens the contacts or poles when the residual current exceeds this reference value.
Any association of devices, each one of them performing separately one or two of the
above-mentioned functions, but acting together in order to accomplish all three functions, is
also covered by this document.
NOTE 2 RCMs (residual current monitor according to IEC 62020) whose purpose is to monitor an electrical
installation and not to provide protection are not covered by this document and cannot be considered similar or
equivalent to DC-RCDs.
DC-RCDs are intended to provide fault protection, the exposed conductive parts of the
installation being connected to an appropriate earth electrode, in accordance with
IEC 60364-4-41.
DC-RCDs having a rated residual operating direct current not exceeding 80 mA are also used
as a provision for additional protection in case of failure of the protective means against
electric shock.
In accordance with IEC 60364-4-42, residual current devices with a rated residual operating
current not exceeding 300 mA can also be used to provide protection against fire hazards due
to a persistent earth fault current.
DC-RCDs are suitable for isolation. They are suitable for all supply systems, with the
exception of single-pole DC-RCDs with two current paths which are not suitable for use in
IT systems.
DC-RCDs of the general type are resistant to unwanted tripping including the case where
surge voltages (as a result of switching transients or induced by lightning) cause loading
currents in the installation without occurrence of flashover.
NOTE 3 Installation and application rules of RCDs are given in IEC 60364 (all parts).
NOTE 4 Surge protective devices installed downstream of DC-RCDs and connected in common mode can cause
unwanted tripping.
The requirements of this document apply for normal environmental conditions (see 7.1).
Additional requirements can apply for RCDs type DC used in locations having severe
environmental conditions.
NOTE 5 For DC-RCDs having a degree of protection higher than IP 20 special constructions can be applicable.
DC-RCDs which include batteries are not covered by this document.
Specific additional requirements for RCDs incorporated or embedded in equipment are
covered in IEC TR 60755. Those specific additional requirements are also applicable for
DC-RCDs.
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 60060-1, High-voltage test techniques – Part 1: General definitions and test requirements
IEC 60060-2, High-voltage test techniques – Part 2: Measuring systems
IEC 60068-2-30:2005, Environmental testing – Part 2-30: Tests – Test Db: Damp heat, cyclic
(12 h + 12 h cycle)
IEC 60068-3-4, Environmental testing – Part 3-4: Supporting documentation and guidance –
Damp heat tests
IEC 60364-4-41:2005, Low-voltage electrical installations – Part 4-41: Protection for safety –
Protection against electric shock
IEC 60417, Graphical symbols for use on equipment (available at http://www.graphical-
symbols.info/equipment)
IEC 60529, Degrees of protection provided by enclosures (IP Code)
IEC 60664-1, Insulation coordination for equipment within low-voltage systems – Part 1:
Principles, requirements and tests
IEC 61000-4-2, Electromagnetic compatibility (EMC) – Part 4-2: Testing and measurement
techniques – Electrostatic discharge immunity test
IEC 61000-4-3, Electromagnetic compatibility (EMC) – Part 4-3 Testing and measurement
techniques – Radiated, radio-frequency, electromagnetic field immunity test
IEC 61000-4-4, Electromagnetic compatibility (EMC) – Part 4-4: Testing and measurement
techniques – Electrical fast transient/burst immunity test
IEC 61000-4-5, Electromagnetic compatibility (EMC) – Part 4-5: Testing and measurement
techniques – Surge immunity test
IEC 61000-4-6, Electromagnetic compatibility (EMC) – Part 4-6: Testing and measurement
techniques – Immunity to conducted disturbances, induced by radio-frequency fields

– 10 – IEC TS 63053:2017 © IEC 2017
IEC 61000-4-16, Electromagnetic compatibility (EMC) – Part 4-16: Testing and measurement
techniques – Test for immunity to conducted common mode disturbances in the frequency
range 0 Hz to 150 kHz
IEC 61000-4-17, Electromagnetic compatibility (EMC) – Part 4-17: Testing and measurement
techniques – Ripple on d.c. input power port immunity test
IEC 61000-6-1, Electromagnetic compatibility (EMC) – Part 6-1: Generic standards –
Immunity for residential, commercial and light-industrial environments
IEC 61000-6-2, Electromagnetic compatibility (EMC) – Part 6-2: Generic standards –
Immunity standard for industrial environments
IEC 61000-6-3, Electromagnetic compatibility (EMC) – Part 6-3: Generic standards –
Emission standard for residential, commercial and light-industrial environments
IEC 61000-6-4, Electromagnetic compatibility (EMC) – Part 6-4: Generic standards –
Emission standard for industrial environments
IEC 61140, Protection against electric shock – Common aspects for installation and
equipment
IEC 61543:1995, Residual current-operated protective devices (RCDs) for household and
similar use – Electromagnetic compatibility
IEC 61543:1995/AMD1:2004
IEC 61543:1995/AMD2:2005
IEC 62873-2, Residual current operated circuit-breakers for household and similar use –
Part 2: Residual current devices (RCDs) – Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62873-2 and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
residual operating direct current
value of residual direct current which causes the DC-RCD to operate under specified
conditions
[SOURCE: IEC 60050-442:1998, 442-05-20, modified – Adapted to DC-RCDs.]
3.2
residual non-operating direct current
value of residual direct current at and below which the DC-RCD does not operate under
specified conditions
[SOURCE: IEC 60050-442:1998, 442-05-21, modified – Adapted to DC-RCDs.]

3.3
residual direct making and breaking capacity
value of a residual prospective direct current which a DC-RCD can make, carry for its opening
time and break under specified conditions of use and behaviour
[SOURCE: IEC 60050-442:1998, 442-05-27, modified – Adapted to DC-RCDs.]
3.4
conditional direct short-circuit current
value of a prospective direct current, which a DC-RCD without integral short-circuit protection,
but protected by a short-circuit protective device in series, can withstand under specified
conditions of use and behaviour
3.5
conditional residual direct short-circuit current
value of a residual direct prospective current, which a DC-RCD without integral short-circuit
protection, but protected by a SCPD in series, can withstand under specified conditions of use
and behaviour
[SOURCE: IEC 60050-442;1998, 442-05-22, modified – Adapted to DC-RCDs.]
3.6
mid-point
common point between two symmetrical circuit elements the opposite ends of which are
electrically connected to different line conductors of the same circuit
[SOURCE: IEC 60050-195:1998, 195-02-04]
3.7
M-pole
part of a DC-RCD associated exclusively with one electrically separated conducting path
intended to connect and to disconnect the mid-point
3.8
time constant
rise time T = L/R (ms) of a prospective direct current to reach a value of 0,632 times the
maximum peak current
4 Classification
4.1 According to the type of installation
4.1.1 DC-RCD for fixed installation and fixed wiring.
4.1.2 Portable DC-RCD with corded connection.
4.2 According to the possibility of adjusting the residual operating current
4.2.1 DC-RCD with a single value of rated residual operating current.
4.2.2 DC-RCD with multiple settings of residual operating current by fixed steps.
4.3 According to time-delay (in presence of a residual current)
4.3.1 DC-RCD without time-delay: for general use, with normal resistance to unwanted
tripping.
– 12 – IEC TS 63053:2017 © IEC 2017
4.3.2 DC-RCD with time-delay: for selectivity, with increased resistance to unwanted
tripping.
4.4 According to the protection against external influences
4.4.1 Enclosed-type DC-RCD (not requiring an appropriate enclosure).
4.4.2 Unenclosed-type DC-RCD (for use with an appropriate enclosure).
4.5 According to the method of mounting
4.5.1 Surface-type DC-RCD.
4.5.2 Flush-type DC-RCD.
4.5.3 Panel board type DC-RCD, also referred to as distribution board type.
NOTE These types can be intended to be mounted on rails.
4.6 According to the method of connection
4.6.1 DC-RCD, the electrical connections of which are not associated with the mechanical
mounting.
4.6.2 DC-RCD, the electrical connections of which are associated with the mechanical
mounting.
NOTE 1 Specific requirements for this classification are under consideration.
NOTE 2 Examples of this type are:
– plug-in type;
– bolt-on type;
– screw-in type.
Some DC-RCDs can be of the plug-in type or bolt-on type on the line side only, the load terminals being usually
suitable for wiring connection.
4.7 According to the type of terminals
4.7.1 DC-RCD with screw-type terminals for external copper conductors.
4.7.2 DC-RCD with screwless type terminals for external copper conductors.
NOTE 1 The requirements for DC-RCDs equipped with these types of terminals are given in IEC 62873-3-1.
4.7.3 DC-RCD with flat quick-connect terminals for external copper conductors.
NOTE 2 The requirements for DC-RCDs equipped with these types of terminals are given in IEC 62873-3-2.
4.7.4 DC-RCD with screw-type terminals for external aluminium conductors.
NOTE 3 The requirements for DC-RCDs equipped with these types of terminals are given in IEC 62873-3-3.
4.8 According to the number of poles and current paths
4.8.1 Single-pole DC-RCD with two current paths.
4.8.2 Two-pole DC-RCD.
4.8.3 Two-pole DC-RCD with three current paths.

4.8.4 Three-pole DC-RCD.
4.9 According to the instantaneous tripping current
This classification applies to the residual current function combined with the circuit-breaker
and is defined in the relevant product standard.
4.10 According to the I²t characteristics
This classification applies to the residual current function combined with the circuit-breaker
and is defined in the relevant product standard.
4.11 According to overcurrent protection
4.11.1 Residual current devices without integral overcurrent protection.
4.11.2 Residual current devices with integral overcurrent protection.
4.11.3 Residual current devices with integral overload protection only.
4.11.4 Residual current devices with integral short-circuit protection only.
4.12 According to the method of construction
4.12.1 DC-RCD completely assembled by the manufacturer as one device (standalone
DC-RCD)
4.12.2 DC-RCD comprised of a circuit-breaker and r.c. unit to be assembled on site
4.12.3 Any association of devices acting together in order to accomplish the three main
functions of a DC-RCD – detection of a residual current, comparison to a reference value and
opening the contacts or poles when the residual current exceeds this reference value.
NOTE The current sensing means and/or the processing device can be mounted separately from the current
breaking device.
4.13 According to the range of ambient air temperature
4.13.1 Residual current devices intended for use between –5 °C and +40 °C.
4.13.2 Residual current devices intended for use between –25 °C and +40 °C.
4.13.3 Residual current devices intended for use in more severe conditions.
4.14 According to the time constant
4.14.1 Residual current devices suitable for DC circuits with a time constant of T ≤ 4 ms.
4.14.2 Residual current devices suitable for DC circuits with a time constant of T ≤ 15 ms.
NOTE It is assumed that short-circuit currents of 1 500 A are not exceeded in installations in which, due to the
loads connected, time constants in normal service up to 15 ms can occur. Where higher short-circuit currents can
occur, the time constant of T = 4 ms is considered sufficient.
4.15 According to the current direction through the poles
4.15.1 Polarised DC-RCD.
4.15.2 Non-polarised DC-RCD.
– 14 – IEC TS 63053:2017 © IEC 2017
5 Characteristics of residual current devices
5.1 Summary of characteristics
The characteristics of the DC-RCD are given in the relevant DC-RCD standard in accordance
with this document.
The characteristics of a DC-RCD shall be stated in the following terms:
– rated voltages (see 5.2.1);
– rated direct current I (see 5.2.2);
n
– rated making and breaking capacity I (see 5.2.3);
m
– rated residual operating direct current I (see 5.2.4);
∆n
– rated residual non-operating direct current I (see 5.2.5);
∆no
– rated residual direct making and breaking capacity I (see 5.2.6);
∆m
(see 5.2.7);
– rated conditional direct short-circuit current I
nc
– rated conditional residual direct short-circuit current I (see 5.2.8);
∆c
– time-delay, if applicable (see 5.2.9);
– operating characteristics (see 5.2.10)
– degree of protection (see IEC 60529).
5.2 Rated quantities and other characteristics
5.2.1 Rated voltages
5.2.1.1 Rated operational voltage (U )
e
The rated operational voltage (hereafter referred to as "rated voltage") of a DC-RCD is the
value of direct voltage, assigned by the manufacturer, to which its performance is referred.
5.2.1.2 Rated insulation voltage (U )
i
The rated insulation voltage of a DC-RCD is the value of voltage, assigned by the
manufacturer, to which dielectric test voltages and creepage distances are referred.
Unless otherwise stated, the rated insulation voltage is the value of the maximum rated
voltage of the DC-RCD. In no case shall the maximum rated voltage exceed the rated
insulation voltage.
5.2.1.3 Rated impulse withstand voltage (U )
imp
The rated impulse withstand voltage of a DC-RCD is defined in the relevant product standard
taking into account the overvoltage category and the rated operational voltage, according to
IEC 60664-1.
5.2.2 Rated direct current (I )
n
A direct current assigned by the manufacturer as the current which the DC-RCD can carry in
uninterrupted duty (see IEC 62873-2), at a specified reference ambient air temperature.
5.2.3 Rated making and breaking capacity (I )
m
The value of the prospective direct current assigned by the manufacturer, which a DC-RCD
can make, carry and break under specified conditions.

5.2.4 Rated residual operating direct current (I )
∆n
The value of residual operating direct current, assigned to the DC-RCD by the manufacturer,
at which the DC-RCD shall operate under specified conditions.
For a DC-RCD having multiple settings of residual operating direct current, the highest setting
is used to designate it.
5.2.5 Rated residual non-operating direct current (I )
∆no
The value of residual non-operating direct current, assigned to the DC-RCD by the
manufacturer, at which the DC-RCD does not operate under specified conditions.
5.2.6 Rated residual direct making and breaking capacity (I )
∆m
The value of the residual prospective direct current, assigned by the manufacturer, which a
DC-RCD can make, carry and break under specified conditions.
5.2.7 Rated conditional direct short-circuit current (I )
nc
The value of the prospective direct current, assigned by the manufacturer, which a DC-RCD,
protected by a specified SCPD, can withstand under specified conditions without undergoing
alterations impairing its functions.
5.2.8 Rated conditional residual direct short-circuit current (I )
∆c
The value of residual prospective direct current, assigned by the manufacturer, which a
DC-RCD, protected by a specified SCPD, can withstand under specified conditions without
undergoing alterations impairing its functions.
5.2.9 Time-delay DC-RCD
Time-delay DC-RCD which complies with the relevant part of Table 3 if applicable.
5.2.10 Operating characteristics
DC-RCD ensures tripping for residual smooth direct currents, whether suddenly applied or
slowly rising, independent of polarity.
5.3 Standard and preferred values
5.3.1 Preferred values of rated operational voltage (U )
e
Preferred values of rated operational voltage are given in Table 1.
Examples for the connection of DC-RCDs in different DC supply systems are given in
Figure 2 a) to d).
...