ISO 17409:2015

Electrically propelled road vehicles -- Connection to an external electric power supply -- Safety requirements

ISO 17409:2015 specifies electric safety requirements for conductive connections of electrically propelled road vehicles to an external electric power supply using a plug or vehicle inlet. It applies to electrically propelled road vehicles with voltage class B electric circuits. In general, it may apply to motorcycles and mopeds if no dedicated standards for these vehicles exist. It applies only to vehicle power supply circuits. It applies also to dedicated power supply control functions used for the connection of the vehicle to an external electric power supply. It does not provide requirements regarding the connection to a non-isolated d.c. charging station. It does not provide comprehensive safety information for manufacturing, maintenance, and repair personnel. The requirements when the vehicle is not connected to the external electric power supply are specified in ISO 6469-3. NOTE 1 This International Standard does not contain requirements for vehicle power supply circuits using protection by class II or double/reinforced insulation but it is not the intention to exclude such vehicle applications. NOTE 2 Requirements for EV supply equipment are specified in IEC 61851.

General Information

• Status: Published
• Publication Date: 22-Oct-2015
• ICS: 43.120 - Electric road vehicles
• Technical Committee: TC 69 - Electrical power/energy transfer systems for electrically propelled road vehicles and industrial trucks
• Current Stage: DELPUB - Deleted Publication
• Start Date: 12-Dec-2023
• Completion Date: 26-Oct-2025

Overview

ISO 17409:2015 - Electrically propelled road vehicles - Connection to an external electric power supply - Safety requirements - defines electrical safety requirements for conductive connections between electrically propelled road vehicles and an external electric power supply using a plug or vehicle inlet. The standard applies to vehicle power supply circuits in voltage class B and to dedicated power-supply control functions used during connection. It excludes connections to non‑isolated d.c. charging stations and does not provide comprehensive safety guidance for manufacturing, maintenance, or repair personnel. Requirements for vehicles when not connected are covered by ISO 6469-3.

Key topics and technical requirements

ISO 17409 organizes safety content around protection, thermal behavior, connectors, and testing. Major topics include:

• Protection against electric shock
  • Basic protection and protection under single‑failure conditions
  • Isolation resistance requirements for A.C. (Modes 1–3) and D.C. (Mode 4)
  • Protection from unintended voltage on contacts and unmated inlets
• Insulation coordination and touch current considerations for safe EV charging
• Thermal and overcurrent protection
  • Overload and short‑circuit protection for A.C. and D.C. connections
  • Arc fault protection and residual energy after disconnection (critical for DC charging)
• Connector and cable requirements
  • Specific requirements for the plug, vehicle inlet and cable assemblies
  • Locking mechanisms for vehicle connectors (AC and DC)
• Additional AC and DC requirements
  • Control pilot functions for DC, disconnection devices, DC isolation resistance monitoring, contact temperature, inrush and fault current behavior
• Operational and documentation requirements
  • Owner’s manual and marking obligations
• Test procedures
  • Isolation resistance, withstand voltage, inrush, touch current and protective conductor resistance tests

Practical applications and users

ISO 17409 is intended for:

• Vehicle manufacturers designing EV high-voltage power circuits and inlets
• Component and connector designers specifying plugs, inlets and cables for conductive charging
• Test laboratories performing safety verification and type testing of vehicle charging interfaces
• Regulators and certification bodies assessing compliance of vehicle-side charging hardware
• EV system architects coordinating vehicle-side safety functions with charging infrastructure

This standard helps ensure safe conductive EV charging interfaces and informs design choices for insulation, fault protection, connector locking, and control functions.

Related standards

• ISO 6469-1 / ISO 6469-3 - vehicle RESS and shock protection when not connected
• IEC 61851 - EV supply equipment (charging stations) requirements
• IEC 62196 - plugs, socket‑outlets, vehicle connectors and vehicle inlets for EVs
• IEC 60309 / IEC 60884 - industrial and household connector standards
• ISO 26262, ISO 20653 - functional safety and environmental protection

Keywords: ISO 17409, electrically propelled road vehicles, external electric power supply, vehicle inlet, plug, EV charging safety, conductive connection, voltage class B, IEC 61851.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 17409
First edition
2015-11-01
Corrected version
2015-12-15
Electrically propelled road vehicles —
Connection to an external electric
power supply — Safety requirements
Véhicules routiers à propulsion électrique — Connexion à une borne
d’alimentation électrique externe — Exigences de sécurité
Reference number
©
ISO 2015
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. [phone]
Fax [phone]
[e-mail]
www.iso.org
ii © ISO 2015 – All rights reserved

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Environmental conditions . 6
5 Requirements for protection of persons against electric shock . 6
5.1 Basic protection . 6
5.2 Protection under single failure conditions . 7
5.3 Isolation resistance . 8
5.3.1 A.C. connection (Mode 1, 2, and 3) . 8
5.3.2 D.C. connection (Mode 4) . 8
5.4 Protection from unintended voltage . 9
5.4.1 Mode 1 . 9
5.4.2 Mode 2 and mode 3 . 9
5.4.3 Mode 4 . 9
5.4.4 Contacts of unmated portion of vehicle inlet .10
5.5 Insulation coordination .10
5.5.1 General.10
5.5.2 A.C. connection (Mode 1, 2, and 3) .10
5.5.3 D.C. connection (Mode 4) .10
6 Protection against thermal incident .10
6.1 Overcurrent protection .10
6.1.1 Overload protection .10
6.1.2 Short-circuit protection for a.c. connection .11
6.1.3 Short-circuit protection for d.c. connection .11
6.2 Arc protection for d.c. connections .12
6.3 Residual energy after disconnection .12
7 Specific requirements for the vehicle inlet, plug, and cable .12
7.1 Requirements for the plug and cable .12
7.2 Requirements for the vehicle inlet .12
8 Additional requirements for a.c. electric power supply .13
8.1 Standard a.c. external electric power supply conditions for operation in service .13
8.2 Current characteristics.13
8.2.1 Load current .13
8.2.2 Inrush current .13
8.3 D.C. fault currents .14
8.4 Touch current .14
8.5 Unintended reverse power flow .14
8.6 Power factor .14
8.7 Locking of the vehicle connector .14
9 Additional requirements for d.c. electric power supply .15
9.1 Disconnection device .15
9.2 Control pilot functions.15
9.3 Vehicle isolation resistance monitoring system .15
9.4 Locking of the vehicle connector .15
9.5 A.C. or D.C. electric power at the same contacts.16
9.6 Contact temperature at vehicle inlet .16
9.7 Overvoltage in case of a load dump .16
9.8 Unintended reverse power flow .17
9.9 Y capacitances .17
10 Operational requirements .17
11 Owner’s manual and marking .17
11.1 Owner’s manual .17
11.2 Marking .17
12 Test procedure .17
12.1 General note on tests .17
12.2 Resistance of protective conductor .17
12.3 Isolation resistance test .17
12.3.1 Preconditioning and conditioning .17
12.3.2 Isolation resistance measurements at the vehicle inlet or plug .18
12.4 Withstand voltage test .18
12.4.1 General.18
12.4.2 Preconditioning and conditioning .19
12.4.3 Test procedure .19
12.4.4 Test voltage .19
12.5 Inrush current tests .20
12.5.1 General.20
12.5.2 Measurement .20
12.6 Touch current .21
Bibliography .23
iv © ISO 2015 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information.
The committee responsible for this document is ISO/TC 22, Road vehicles, Subcommittee SC 37,
Electrically propelled vehicles.
This corrected version of ISO 17409:2015 incorporates the following corrections.
6.1.2 and 6.1.3: The phrase ‘overload protection’ has been replaced with ‘short-circuit protection’ in
four places.
INTERNATIONAL STANDARD ISO 17409:2015(E)
Electrically propelled road vehicles — Connection to an
external electric power supply — Safety requirements
1 Scope
This International Standard specifies electric safety requirements for conductive connections of
electrically propelled road vehicles to an external electric power supply using a plug or vehicle inlet.
It applies to electrically propelled road vehicles with voltage class B electric circuits. In general, it may
apply to motorcycles and mopeds if no dedicated standards for these vehicles exist.
It applies only to vehicle power supply circuits. It applies also to dedicated power supply control
functions used for the connection of the vehicle to an external electric power supply.
It does not provide requirements regarding the connection to a non-isolated d.c. charging station.
It does not provide comprehensive safety information for manufacturing, maintenance, and repair
personnel.
The requirements when the vehicle is not connected to the external electric power supply are specified
in ISO 6469-3.
NOTE 1 This International Standard does not contain requirements for vehicle power supply circuits
using protection by class II or double/reinforced insulation but it is not the intention to exclude such vehicle
applications.
NOTE 2 Requirements for EV supply equipment are specified in IEC 61851.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 6469-1, Electrically propelled road vehicles — Safety specifications — Part 1: On-board rechargeable
energy storage system (RESS)
ISO 6469-3, Electrically propelled road vehicles — Safety specifications — Part 3: Protection of persons
against electric shock
ISO 13849 (all parts), Safety of machinery — Safety-related parts of control systems
ISO 20653, Road vehicles — Degrees of protection (IP code) — Protection of electrical equipment against
foreign objects, water and access
ISO 26262 (all parts), Road vehicles — Functional safety
IEC 60309-1, Plugs, socket-outlets and couplers for industrial purposes — Part 1: General requirements
IEC 60309-2, Plugs, socket-outlets and couplers for industrial purposes — Part 2: Dimensional
interchangeability requirements for pin and contact-tube accessories
IEC 60364-4-43, Electrical installations of buildings — Part 4-43: Protection for safety — Protection
against overcurrent
IEC 60364-5-54, Low-voltage electrical installations — Part 5-54: Selection and erection of electrical
equipment — Earthing arrangements and protective conductors
IEC 60364-6, Low-voltage electrical installations — Part 6: Verification
IEC 60664 (all parts), Insulation coordination for equipment within low-voltage systems
IEC 60884-1, Plugs, socket-outlets and couplers for household and similar purposes — Part 1: General
requirements
IEC 61851-1, Electric vehicle conductive charging system — Part 1: General requirements
IEC 61851-23, Electric vehicle conductive charging system — Part 23: D.C. electric vehicle charging station
IEC 62196-1, Plugs, socket-outlets, vehicle connectors and vehicle inlets — Conductive charging of electric
vehicles — Part 1: General requirements
IEC 62196-2, Plugs, socket-outlets, vehicle connectors and vehicle inlets — Conductive charging of electric
vehicles — Part 2: Dimensional compatibility and interchangeability requirements for a.c. pin and contact-
tube accessories
IEC 62196-3, Plugs, socket-outlets, vehicle connectors and vehicle inlets — conductive charging of electric
vehicles — Part 3: Dimensional compatibility and interchangeability requirements for dedicated d.c. and
combined a.c./d.c. pin and contact-tube vehicle couplers
ISO/IEC 15118 (all parts), Road vehicles — Vehicle to grid communication interface
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
balance of electric power system
remaining portion of a voltage class B electric circuit when all RESS and fuel cell stacks are disconnected
3.2
barrier
part providing protection against direct contact from any usual direction of access
3.3
basic insulation
insulation of hazardous-live-parts which provides basic protection
3.4
case A
connection of an EV to the a.c. supply network (mains) utilizing a supply cable and plug permanently
attached to the EV
3.5
case B
connection of an EV to the a.c. supply network (mains) utilizing a detachable cable assembly with a
vehicle connector and a.c. EV supply equipment
3.6
case C
connection of an EV to the a.c. supply network (mains) utilizing a supply cable and vehicle connector
permanently attached to the EV supply equipment.
Note 1 to entry: Only case C is applicable for mode 4 (see IEC 61851–1).
3.7
charger
power converter at the vehicle power supply circuit which supplies electric power, e.g. for charging a RESS
2 © ISO 2015 – All rights reserved

3.8
conductive part
part capable of conducting electric current
3.9
control pilot circuit
circuit designed for the transmission of signals and/or communication between an EV and an EV
supply equipment
3.10
control pilot conductor
insulated conductor incorporated in an EV cable assembly that creates, together with the protective
conductor, the control pilot circuit
3.11
control pilot function
functionality used to monitor and control the interaction between the electric vehicle and the
supply equipment
3.12
d.c. EV charging station
EV supply equipment intended to supply d.c. current to an EV
3.13
direct contact
contact of persons with live parts
3.14
distortion power factor
product of the displacement power factor and the total harmonic distortion up to the 40th harmonics of
the load current
3.15
displacement power factor
power factor due to the phase shift between voltage and current at the fundamental line frequency
3.16
double insulation
insulation comprising both basic insulation and supplementary insulation
3.17
electric chassis
conductive parts of a vehicle that are electrically connected and whose potential is taken as reference
3.18
electric shock
physiological effect resulting from an electric current passing through a human body
3.19
electric vehicle
electric road vehicle
EV
any vehicle propelled by an electric motor drawing current from a RESS intended primarily for use
on public roads
3.20
enclosure
part providing protection of equipment against direct contact from any direction
3.21
EV supply equipment
equipment or combined equipment providing dedicated functions for an electric power supply from
a fixed installation to an EV for the purpose of charging for all dedicated charging modes and cases
of connection
3.22
exposed conductive part
conductive part of the electric equipment, which can be touched by a test finger according to IPXXB (see
ISO 20653) after removing barriers/enclosures which can be removed without using tools and which is
not normally live, but which can become live under fault conditions
3.23
external electric power supply
electric power source that is not part of the vehicle for supplying electric energy to an EV using an EV
supply equipment
3.24
hazard
potential source of harm
3.25
isolation resistance
resistance between live parts of voltage class B electric circuit and the electric chassis, as well as the
voltage class A system
3.26
live conductor (line and neutral)
conductor which is energized in normal operation and capable of contributing to the transmission or
distribution of electric energy
3.27
live part
conductor or conductive part intended to be electrically energized in normal operation
3.28
maximum working voltage
highest value of a.c. voltage (rms) or of d.c. voltage which can occur in an electric system under any
normal operating conditions according to manufacturer’s specifications, disregarding transients
3.29
mode 1
connection of the EV to the a.c. supply network (mains) utilizing a cable and plug, that is not fitted with
any supplementary pilot or auxiliary contacts, and connects to a standard socket-outlet
3.30
mode 2
connection of the EV to the a.c. supply network (mains) utilizing a cable and plug connected to a
standard socket-outlet, with a control pilot function and system for personal protection against electric
shock placed between the EV and the socket outlet
3.31
mode 3
connection of the EV utilizing EV supply equipment permanently connected to the a.c. supply network
(mains) and where the control pilot function extends to control equipment in the EV supply equipment
Note 1 to entry: Mode 3 includes the use of cable assembly not permanently connected to the a.c supply network
(case A and case B).
4 © ISO 2015 – All rights reserved

3.32
mode 4
connection of the EV to the a.c. or d.c. supply network (mains) utilizing a d.c. EV supply equipment or
d.c. EV charging station using a control pilot function
3.33
non-isolated d.c. EV charging station
d.c. EV charging station with d.c. circuit on output side which is not electrically separated by at least
basic insulation from the supply system
3.34
plug
accessory having contacts designed to engage with the contacts of a socket-outlet, also incorporating
means for the electrical connection and mechanical retention of flexible cables or cords
3.35
protective conductor (PE)
conductor provided for purposes of safety, for example protection against electric shock
3.36
rechargeable energy storage system
RESS
system that stores energy for delivery of electric energy and which is rechargeable
EXAMPLE Batteries and capacitors.
3.37
reinforced insulation
insulation of hazardous-live-parts which provides a degree of protection against electric shock
equivalent to double insulation
Note 1 to entry: Reinforced insulation may comprise several layers which cannot be tested singly as basic
insulation or supplementary insulation.
3.38
residual current device
RCD
mechanical switching device or association of devices designed to make, carry and break currents
under normal service conditions and to cause the opening of the contacts when the residual current
attains a given value under specified conditions
Note 1 to entry: A residual current device can be a combination of various separate elements designed to detect
and evaluate the residual current and to make and break current.
3.39
socket-outlet
accessory having socket-contacts designed to engage with the contacts of a plug and having terminals
for the connection of cables or cords
3.40
standard plug and socket-outlet
plug and socket-outlet which meets the requirements of any IEC and/or national standard that
provides interchangeability by standard sheets, excluding the specific EV accessories as defined in the
IEC 62196 series
Note 1 to entry: The standards IEC 60309–1, IEC 60309–2, and IEC 60884–1 define standard plugs and
socket-outlets.
3.41
supplementary insulation
independent insulation applied in addition to basic insulation for fault protection
3.42
touch current
electric current passing through a human body or through an animal body when it touches one or more
accessible parts of an electrical installation or electrical equipment
3.43
vehicle connector
part of a vehicle coupler integral with or intended to be attached to the cable assembly
3.44
vehicle coupler
means of enabling the manual connection of a flexible cable to an EV for the purpose of supplying
electric energy to an EV
Note 1 to entry: It consists of two parts: a vehicle connector and a vehicle inlet.
3.45
vehicle inlet
part of a vehicle coupler incorporated in, or fixed to, an electric vehicle
3.46
vehicle isolation resistance monitoring system
system which periodically or continuously monitors the isolation resistance between live parts of
voltage class B electric circuits and the electric chassis
3.47
vehicle power supply circuit
voltage class B electric circuit which includes all parts that are galvanically connected to the vehicle
inlet (case B, case C) or the plug (case A) and that is operational when connected to an external
electric power supply
3.48
voltage class A
classification of an electric component or circuit as belonging to voltage class A, if its maximum working
voltage is ≤30 V a.c. (rms) or ≤60 V d.c., respectively
3.49
voltage class B
classification of an electric component or circuit as belonging to voltage class B, if its maximum working
voltage is (>30 V and ≤1 000) V a.c. (rms) or (>60 V and ≤1 500) V d.c., respectively
4 Environmental conditions
The requirements given in this International Standard shall be met across the range of environmental
conditions for which the electric vehicle is designed to operate when connected to an external electric
power supply, as specified by the vehicle manufacturer.
NOTE See ISO 16750-4 for guidance.
5 Requirements for protection of persons against electric shock
5.1 Basic protection
In this Clause, requirements for protection against direct contact at the vehicle inlet (case B and C) and
at the plug (case A) are specified.
Standard plug mated with standard socket-outlet (case A) shall comply with the requirements of relevant
standards and the national requirements of the country where the product is placed on the market.
6 © ISO 2015 – All rights reserved

Plug according to IEC 62196 mated with socket-outlet according to IEC 62196 (case A) shall comply with
the degree of protection IPXXD at minimum in accordance with ISO 20653.
Mated portion of the vehicle inlet mated with vehicle connector (case B and case C) shall comply with
IPXXD at minimum in accordance with ISO 20653. The requirements for unmated contacts of such a
vehicle inlet are specified in 5.4.
5.2 Protection under single failure conditions
For mode 1, 2, 3, and 4, the plug (case A) or the vehicle inlet (case B and case C) shall have a contact for
connecting the vehicle electric chassis to the protective conductor of an external electric power supply.
To provide protection under single failure conditions, at least one of the following requirements shall
be fulfilled.
— The protective conductor terminal of the plug (case A) or the vehicle inlet (case B and case C) shall
be connected to the vehicle electric chassis fulfilling the requirements for protective conductor
connection. All exposed conductive parts of the vehicle power supply circuit shall be connected to
the vehicle electric chassis fulfilling the requirements for the protective conductor connection. An
example for this option is given in Figure 1.
7 6
Key
1 vehicle power supply circuit 5 electric chassis
2 charger with galvanic separation 6 protective conductor
3 RESS 7 protective conductor
4 potential equalization according to ISO 6469 8 vehicle inlet
Figure 1 — Connection between protective conductor and electric chassis (example for Option 1)
— The protective conductor terminal of the plug (case A) or the vehicle inlet (case B and case C)
shall be connected to exposed conductive parts of the vehicle power supply circuit fulfilling the
requirements for protective conductor connection. All exposed conductive parts of the vehicle
power supply circuit shall be connected to the vehicle electric chassis fulfilling the requirements
for protective conductor connection. An example for this option is given in Figure 2.
Key
1 vehicle power supply circuit 5 electric chassis
2 charger with galvanic separation 6 protective conductor
3 RESS 7 protective conductor
4 potential equalization according to ISO 6469 8 vehicle inlet
Figure 2 — Connection between protective conductor and electric chassis (example for Option 2)
The cross-sectional area of the protective conductor shall be designed in accordance with IEC 60364-5-54.
For the specification of the protective conductor of a vehicle power supply circuit used for a d.c.
connection, a fault current and the disconnecting time in case of a fault current in accordance with
IEC 61851-23 shall be considered.
The resistance of the protective conductor connection between the protective conductor contact of
the plug (case A) or the vehicle inlet (case B, case C) and the vehicle electrical chassis, as well as all
exposed conductive parts of the vehicle power supply circuit shall be less than 0,1 Ω. All paths used for
protective conductor connection shall be considered.
The resistance of protective conductor shall be tested in accordance with 12.2.
NOTE Protective conductor requirement for double/reinforced insulation is under consideration.
5.3 Isolation resistance
5.3.1 A.C. connection (Mode 1, 2, and 3)
The total isolation resistance of the vehicle power supply circuit shall be at least 500 Ω/V when the
vehicle is not connected to an external electric power supply. The reference shall be the maximum
working voltage of the relevant electric circuit.
Compliance shall be tested in accordance with 12.3.
5.3.2 D.C. connection (Mode 4)
The isolation resistance of the vehicle power supply circuit shall comply with the requirements in
ISO 6469-3 when the vehicle connector is not mated with the vehicle inlet.
Compliance shall be tested in accordance with 12.3.
8 © ISO 2015 – All rights reserved

5.4 Protection from unintended voltage
5.4.1 Mode 1
The plug (case A) or vehicle inlet (case B and case C) shall comply with at least one of the following
requirements:
— the charge between any contacts shall be below 50 µC within 1 s after cut off of the external
electric power supply;
— the voltage between any contacts shall be below or equal to 60 V d.c. and 30 V a.c. (rms) within 1 s
after cut off of the external electric power supply.
For compliance, cut off of external electric power supply can be simulated by unmating the plug (case A)
or the vehicle connector (case B and case C).
NOTE Cut off of external electric power supply means loss of supply voltage, including disconnection and
voltage outage on the supply.
5.4.2 Mode 2 and mode 3
The plug (case A) or vehicle inlet (case B and case C) shall comply with at least one of the following
requirements if their voltage class B live parts are not protected at least by IPXXB in accordance
with ISO 20653:
— the charge between any contacts shall be below 50 µC within 1 s after disconnection of the vehicle
from external electric power supply;
— the voltage between any contacts shall be below or equal to 60 V d.c. and 30 V a.c. (rms) within 1 s
after disconnection of the vehicle from external electric power supply.
The plug (case A) or vehicle inlet (case B and case C) shall comply with at least one of the following
requirements if their voltage class B live parts are protected at least by IPXXB in accordance with
ISO 20653:
— the energy between any contacts shall be below 0,2 J within 10 s after disconnection of the vehicle
from external electric power supply;
— the voltage between any contacts shall be below or equal to 60 V d.c. and 30 V a.c. (rms) within 10 s
after disconnection of the vehicle from external electric power supply.
For case B and case C, the voltage or energy shall be measured at the unmated vehicle inlet.
5.4.3 Mode 4
The vehicle inlet shall comply with at least one of the following requirements if its voltage class B live
parts are not protected at least by IPXXB in accordance with ISO 20653:
— the charge between any contacts shall be below 50 µC within 1 s after disconnection of the vehicle
from external electric power supply;
— the voltage between any contacts shall be below or equal to 60 V d.c. and 30 V a.c. (rms) within 1 s
after disconnection of the vehicle connector from external electric power supply.
The vehicle inlet shall comply with at least one of the following requirements if its voltage class B live
parts are protected at least by IPXXB in accordance with ISO 20653:
— the energy between any contacts shall be below 0,2 J within 10 s after disconnection of the vehicle
from external electric power supply;
— the voltage between any contacts shall be below or equal to 60 V d.c. and 30 V a.c. (rms) within 10 s
after disconnection of the vehicle from external electric power supply.
The voltage or energy shall be measured at the unmated vehicle inlet
5.4.4 Contacts of unmated portion of vehicle inlet
The contacts of an unmated portion of the vehicle inlet shall fulfil at least one of the following
requirements, when the other contacts of this vehicle inlet are mated with a vehicle connector (e.g. d.c.
contacts of a combined vehicle inlet unmated and other contacts mated with a type 1 or type 2 vehicle
connector according to IEC 62196 series):
— the energy between any unmated contacts shall be below 0,2 J if live parts are protected at least by
IPXXB in accordance with ISO 20653;
— the voltage between any unmated contacts shall be below or equal to 60 V d.c. and 30 V a.c. (rms) if
live parts are protected at least by IPXXB in accordance with ISO 20653;
— the charge between any contacts shall be below 50 µC if live parts are not protected at least by
IPXXB in accordance with ISO 20653.
5.5 Insulation coordination
5.5.1 General
The vehicle power supply circuit shall fulfil the applicable sections of IEC 60664 series on insulation
coordination and meet the withstand voltage capability according to the details in 5.5.2 or 5.5.3.
Neither dielectric breakdown nor flashover shall occur during the withstand voltage test.
Compliance shall be tested in accordance with 12.4.
5.5.2 A.C. connection (Mode 1, 2, and 3)
The vehicle power supply circuit shall be designed according to the overvoltage category II unless
appropriate overvoltage reduction in accordance with IEC 60664-1 is provided in the vehicle power
supply circuit.
5.5.3 D.C. connection (Mode 4)
The vehicle power supply circuit shall be designed according to a rated impulse voltage of at least 2 500 V.
NOTE IEC 61851–23 has adopted this fixed value of the rated impulse voltage independent of input voltage of
d.c. charging station
6 Protection against thermal incident
6.1 Overcurrent protection
6.1.1 Overload protection
The cross-sectional area of the live conductors of the vehicle power supply circuit, as well as the rated
current of the plug (case A) or vehicle inlet (case B and case C), shall be according to the maximum load
current of the vehicle unless parts of this circuit are separately protected by an overcurrent protection
device in the vehicle. (e.g. fuse, circuit breaker, etc.).
10 © ISO 2015 – All rights reserved

6.1.2 Short-circuit protection for a.c. connection
For short-circuit current supplied by external power supply, the requirements in a), b), or c) shall
be fulfilled.
a) The cross-sectional area of the live conductors of the vehicle power supply circuit shall have a
short-circuit current withstand rating (I t) according to the characteristics of the overcurrent
protection device of the external electric power supply. For the connection to an external electric
power supply with a rated current up to 80 A, the vehicle power supply circuit shall have a short-
2 2 2
circuit current withstand rating (I t) of at least 80 000 A s. I t value shall be calculated according
to IEC 60364-4-43.
NOTE Breaking time for overcurrent protection device is less than 0,1 s (see IEC 60364–4-43).
b) An overcurrent protection device (e.g. fuse, circuit breaker) shall be provided in each live conductor
of the vehicle power supply circuit. The cross-sectional area of the live conductor downstream
this overcurrent protection device shall be designed according to the rating of this overcurrent
protection device.
c) For case B and case C, all of the following requirements shall be fulfilled:
— cross-sectional area of the vehicle power supply circuits shall be designed according to the
maximum load current of the vehicle;
— protection against mechanical damage for vehicle power supply circuit wiring between the
vehicle inlet and the charger shall be provided so that single failure does not cause insulation
fault between live conductors and between live conductors and electrical chassis;
— an overcurrent protection device (e.g. fuse, circuit breaker) shall be provided inside the charger.
The overcurrent protection device rating and short-circuit current interrupt rating shall be
sufficient to protect the wiring of the vehicle power supply circuit between the vehicle inlet and
the on-board charger.
For short-circuit current supplied by power sources of the vehicle, short-circuit protection shall be
provided for the vehicle power supply circuit.
6.1.3 Short-circuit protection for d.c. connection
For short-circuit current supplied by external electric power supply, the requirements in a) or b) shall
be fulfilled for short-circuit protection.
a) The cross-sectional area of the live conductors of the vehicle power supply circuit shall have a
short-circuit current withstand rating (I t) of at least the following values:
— 1 000 000 A s for System A according to IEC 61851-23;
— 5 000 000 A s for System C according to IEC 61851-23;
— a value in A s to be coordinated for any other d.c.-EV charging station.
I t value of the live conductors shall be calculated according to IEC 60364-4-43.
NOTE 1 This short-circuit current withstand rating (I t) corresponds to the characteristics of the
overcurrent protection device of the external electric power supply.
b) An overcurrent protection device (e.g. fuse, circuit breaker) shall be provided in the vehicle power
supply circuit. The cross-sectional area of the live conductors to be protected by this overcurrent
protection device shall be designed according to the short-circuit interrupt rating of this
overcurrent protection device. The cross-sectional area of the live conductors upstream from this
overcurrent protection device (to vehicle inlet) shall comply with the requirement of a).
The breaking time for interruption of a short-circuit current shall be gathered from the technical data
of the selected overcurrent protection device.
For short-circuit current supplied by vehicle sources, the vehicle power supply circuit shall have an
overcurrent protection device with a rating not higher than following values:
— 2 500 000 A s for System A according to IEC 61851-23;
— 12 000 000 A s for System C according to IEC 61851-23;
— a value in A s to be coordinated for any other d.c. EV charging station.
The cross-sectional area of the live conductors of the vehicle power supply circuit upstream from
this overcurrent protection device (to vehicle inlet) shall be designed according to the rating of the
overcurrent protection device of the vehicle power supply circuit.
I t value of the live conductors shall be calculated according to IEC 60346-4-43.
NOTE 2 This characteristics of the overcurrent protection device (I t) corresponds to the short-circuit
current withstand rating of the live conductors of an external electric power supply, if no additional overcurrent
protection device is provided, see e.g. IEC 61851–23.
6.2 Arc protection for d.c. connections
Arc protection is covered by the requirements in 9.4.
6.3 Residual energy after disconnection
One second after having disconnected the vehicle from the external electric power supply, the stored
energy at the voltage class B live parts at the plug (case A) or vehicle inlet
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