ISO 13063-3:2022

INTERNATIONAL ISO
STANDARD 13063-3
First edition
2022-07
Electrically propelled mopeds and
motorcycles — Safety specifications —
Part 3:
Electrical safety
Cyclomoteurs et motocycles à propulsion électrique — Spécifications
de sécurité —
Partie 3: Sécurité électrique
Reference number
© ISO 2022
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Published in Switzerland
ii
Contents Page
FOREWORD .v
1 Scope . 1
2 Normative references . 1
3  Terms and definitions . 1
4 Abbreviated terms . 7
5 Voltage classes .7
6 General requirements . 8
6.1 Environmental and operational conditions . 8
6.2 Marking . 8
6.2.1 Marking of voltage class B electric components . 8
6.2.2 Marking of voltage class B wiring . 8
7 Requirements for protection against electric shock . 8
7.1 General requirements . 8
7.1.1 General requirements for connected sections of a circuit . 8
7.1.2 General requirements for voltage class B . 9
7.1.3 Requirements for voltage class A . 9
7.1.4 Requirements of voltage class A power cables and conduits. 10
7.2 Basic protection . 10
7.3 Fault protection and additional measures . 10
7.3.1 Equipotential bonding . 10
7.3.2 Isolation resistance . 11
7.3.3 Provisions for capacitive coupling and capacitive discharge .12
7.3.4 Alternative electrical or mechanical measures .12
7.3.5 De-energization . 13
7.3.6 Provision for chassis-connected voltage class B circuit .13
7.4 General requirements for protective provisions . 13
7.4.1 General .13
7.4.2 Requirements for insulation of voltage class B .13
7.4.3 Requirements of protective barrier and protective enclosures of voltage
class B electric components . 14
7.5 Requirements for connectors . 14
7.6 Insulation coordination . 15
7.7 Alternative approach for protection against electric shock . 15
8 Protection against thermal incidents .15
8.1 Overload protection . 15
8.2 Short-circuit protection . 15
9 Requirements for vehicle power supply circuit .15
10 Owner’s guide manual .15
11 Test procedures .16
11.1 General . 16
11.2 Continuity test for equipotential bonding . 16
11.3 Isolation resistance measurements for voltage class B electric circuits . 16
11.3.1 Preconditioning and conditioning . 16
11.3.2 Isolation resistance measurements of the balance of electric circuits. 16
11.3.3 Isolation resistance measurement of the voltage class B electric power
sources . 17
11.3.4 Isolation resistance measurement of entire electric circuits. 19
11.4 Test for isolation resistance monitoring system . 19
11.5 Touch current. 19
11.6 Withstand voltage test .20
iii
11.6.1 General .20
11.6.2 Preconditioning and conditioning . 20
11.6.3 Test procedure. 21
11.6.4 Test criteria . 21
11.7 Test method of voltage class A wiring . 21
11.7.1 Test method for the movable part of the voltage class A wiring . 21
11.7.2 Test method for withstand voltage . 21
Bibliography .23
iv
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 of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 38,
Motorcycles and mopeds.
This first edition of ISO 13063-3, together with ISO 13063-1 and ISO 13063-2, cancels and replaces
ISO 13063:2012, which has been technically revised.
The main changes are as follows:
— extension of protection against electric shock to all electric safety requirements;
— alignment of structure and requirements as possible with ISO 6469-3:2018;
— splitting the document into three documents which consist of the following parts, under the general
title Electrically propelled mopeds and motorcycles — Safety specifications:
— Part 1: On-board rechargeable energy storage system (RESS);
— Part 2: Vehicle operational safety;
— Part 3: Electrical safety;
— addition of specific requirements for capacitive discharge;
— new test specification for the isolation resistance monitoring system;
— new requirements and test for touch current; and
— the requirements for conductive connection to an external electric power supply can be covered by
ISO 18246.
A list of all parts in the ISO 13063 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
INTERNATIONAL STANDARD ISO 13063-3:2022(E)
Electrically propelled mopeds and motorcycles — Safety
specifications —
Part 3:
Electrical safety
1 Scope
This document specifies electric safety requirements for protection against electric shock and thermal
incidents of electric propulsion systems and conductively connected auxiliary electric systems of-
electrically propelled mopeds and motorcycles when used in normal conditions. It is applicable to a
maximum working voltage of the on-board electrical circuit up to 1 000 V alternating current (a.c.) or
1 500 V direct current (d.c.). This document does not provide comprehensive safety information for
manufacturing, maintenance and repair personnel.
NOTE Requirements for conductive connections of electrically propelled mopeds and motorcycles to an
external electric power supply are described in ISO 18246.
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.
ISO 20653, Road vehicles — Degrees of protection (IP-code) — Protection of electrical equipment against
foreign objects, water and access
IEC 60227-1, Polyvinyl chloride insulated cables of rated voltages up to and including 450/750 V — Part 1:
General requirements
IEC 60245-1, Rubber insulated cables — Rated voltages up to and including 450/750 V — Part 1: General
requirements
IEC 60990:2016, Methods of measurement of touch current and protective conductor current
3  Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
auxiliary electric system
vehicle system, other than the propulsion system (3.46), that operates on electric energy
[SOURCE: ISO 6469-3:2021, 3.1]
3.2
balance of electric circuit
remaining section of an electric circuit when all electric power sources that are energized (e.g. RESS
(3.23) and fuel cell stacks) are disconnected
[SOURCE: ISO 6469-3:2021, 3.2]
3.3
protective barrier
part providing protection against direct contact (3.9) from any usual direction of access
[SOURCE: IEC 60050-826:2004, 826-12-23, modified — Domain “” was removed.]
3.4
basic insulation
insulation of hazardous live parts (3.35) which provides basic protection (3.5)
Note 1 to entry: This concept does not apply to insulation used exclusively for functional purposes.
Note 2 to entry: Where insulation is not provided by solid insulation only, it is complemented with protective
barriers (3.3) or protective enclosures (3.15) to prevent access to live parts (3.19) in order to achieve basic
protection.
[SOURCE: IEC 60050-581:2008, 581-21-24, modified — “Note 2 to entry was added.]
3.5
basic protection
protection against electric shock (3.13) under fault-free conditions.
[SOURCE: IEC 60050-195:2021, 195-06-01, modified — "normal" was replaced by "fault-free".]
3.6
conductive part
part which can carry electric current
[SOURCE: IEC 60050-195:2021, 195-01-06]
3.7
conductor
conductive part (3.6) intended to carry a specified electric current
[SOURCE: IEC 60050-195:2021, 195-01-07]
3.8
creepage distance
shortest distance along the surface of a solid insulating material between two conductive parts (3.6)
[SOURCE: IEC 60050-151:2001, 151-15-50]
3.9
direct contact
electric contact of persons or animals with live parts (3.19)
[SOURCE: IEC 60050-826:2004, 826-12-03]
3.10
double insulation
insulation comprising both basic insulation (3.4) and supplementary insulation (3.25)
[SOURCE: IEC 60050-195:2021, 195-06-08]
3.11
electric chassis
conductive parts (3.6) of a vehicle that are electrically connected and whose potential is taken as
reference
3.12
electric drive
combination of traction motor, power electronics and their associated controls for the conversion of
electric to mechanical power and vice versa
[SOURCE: ISO 6469-3:2021, 3.13]
3.13
electric shock
physiological effect resulting from an electric current passing through a human body or animal body
[SOURCE: IEC 60050-826:2004, 826-12-01]
3.14
electrically propelled vehicle
vehicle with one or more electric drive(s) (3.12) for vehicle propulsion
[SOURCE: ISO 6469-3:2021, 3.15]
3.15
protective enclosure
electrical enclosure surrounding internal parts of equipment to prevent access to hazardous live parts
(3.35) from any direction
[SOURCE: IEC 60050-195:2021, 195-06-14, modified — Domain “” was removed.]
3.16
exposed conductive part
conductive part (3.6) of equipment which can be touched and which is not normally live, but which can
become live when basic insulation (3.4) fails
Note 1 to entry: A conductive part of electrical equipment which can become live only through contact with an
exposed conductive part which has become live is not considered to be an exposed conductive part itself.
[SOURCE: IEC 60050-442:1998, 442-01-21]
3.17
isolation resistance monitoring system
system that periodically or continuously monitors the isolation resistance (3.18) between live parts
(3.19) and the electric chassis (3.11)
[SOURCE: ISO 6469-3:2021, 3.24]
3.18
isolation resistance
insulation resistance
resistance between live parts (3.19) of an electric circuit and the electric chassis (3.11) as well as other
electric circuits which are insulated from this electric circuit
[SOURCE: ISO 6469-3:2021, 3.23]
3.19
live part
conductor (3.7) or conductive part (3.6) intended to be energized in normal use, but by convention not
the electric chassis (3.11)
[SOURCE: IEC 60050-442:1998, 442-01-40, modified — “including a neutral conductor” and Note were
removed, and "combined protective and neutral conductor (PEN)" was replaced by "electric chassis".]
3.20
maximum working voltage
highest value of AC voltage (rms) or of DC voltage that can occur under any normal operating conditions
according to the manufacturers’ specifications, disregarding transients and ripple
[SOURCE: ISO 6469-3:2021, 3.26]
3.21
equipotential bonding
provision of electric connections between conductive parts (3.6), intended to achieve equipotentiality
[SOURCE: IEC 60050-826:2004, 826-13-19]
3.22
degree of protection
IP
protection provided by an enclosure or barriers against access, foreign objects and/or water and
verified by standardized test methods in accordance with ISO 20653
[SOURCE: ISO 20653:2013, 3.2, modified — The term "IP" and the phrase “in accordance with ISO 20653”
were added.]
3.23
rechargeable energy storage system
RESS
rechargeable system that stores energy for delivery of electric energy for the electric drive (3.12)
EXAMPLE Battery, capacitor, flywheel.
[SOURCE: ISO 6469-3:2021, 3.31]
3.24
reinforced insulation
insulation of hazardous live parts (3.35) which provides protection against electric shock (3.13)
equivalent to double insulation (3.10)
Note 1 to entry: Reinforced insulation may comprise several layers that cannot be tested singly as basic insulation
(3.4) or supplementary insulation (3.25).
[SOURCE: IEC 60050-581:2008, 581-21-27]
3.25
supplementary insulation
independent insulation applied in addition to basic insulation (3.4) for fault protection (3.29)
[SOURCE: IEC 60050-195:2021, 195-06-07]
3.26
voltage class
classification of an electric component or circuit according to its maximum working voltage (3.20)
[SOURCE: ISO 6469-3:2021, 3.36]
3.27
wiring
system of wires providing electric circuits and including cables and connectors
3.28
service disconnect
device for deactivation of the electrical circuit when conducting checks and services of the vehicle, RESS
(3.23), etc.
3.29
fault protection
protection against electric shock (3.13) under single-fault conditions
[SOURCE: IEC 60050-195:2021, 195-06-02]
3.30
functional insulation
insulation between conductive parts (3.6), necessary for the proper functioning of the component
[SOURCE: IEC 60050-195:2021, 195-02-41, modified — "equipment" replaces "component".]
3.31
touch current
electric current passing through a human body or through livestock when it touches one or more
accessible parts of cables or equipment
[SOURCE: ISO 17409:2020, 3.57, modified — “cables” replaces “an installation”.]
3.32
vehicle power supply circuit
voltage class (3.26) B electric circuit which includes all parts that are conductively connected to the
vehicle inlet (3.33) [case B (3.40), case C (3.41)] or the plug (3.45) [case A (3.39)]
[SOURCE: ISO 6469-2:2022, 3.18, modified — “conductively” replaces “galvanically” and "and that is
operational when connected to an external electric power supply" was deleted.]
3.33
vehicle inlet
part of a vehicle coupler incorporated in, or fixed to, the electric vehicle
[SOURCE: IEC 62196-1:2014, 3.3.2, modified — "electric vehicle inlet" was deleted.]
3.34
removable RESS
RESS (3.23) that by design can be taken out from the vehicle by the vehicle user for off-board charging
and/or other operation
3.35
hazardous live part
live part (3.19) which, under certain conditions, can give a harmful electric shock (3.13)
Note 1 to entry: For guidance on harmful physiological effects see IEC 61140:2016.
[SOURCE: IEC 60050-195:2021, 195-06-05, modified —Note 1 to entry was replaced.]
3.36
specific voltage condition
condition that the maximum voltage of a conductively connected electric circuit between a DC live part
(3.19) and any other live part (DC or AC) is ≤ 30 V a.c. (rms) and ≤ 60 V d.c.
Note 1 to entry: When a DC live part of such an electric circuit is connected to chassis and the specific voltage
condition applies, the maximum voltage between any live part and the electric chassis (3.11) is ≤ 30 V a.c. (rms)
and ≤ 60 V d.c.
Note 2 to entry: For pulsating DC voltages (alternating voltages without change of polarity) the DC threshold is
applied.
3.37
chassis-connected electric circuit
electric circuit that is conductively connected to each other, where the DC part of this circuit is
connected to the electric chassis (3.11) and the specific voltage condition (3.36) is fulfilled
3.38
clearance
shortest distance in air between two conductive parts (3.6)
[SOURCE: IEC 60050-581:2008, 581-27-76]
3.39
case A
connection of an EV to the supply network with a plug (3.45) and cable permanently attached to the EV
[SOURCE: IEC 61851-1:2017, 3.1.10]
3.40
case B
connection of an EV to the AC supply network with a cable assembly detachable at both ends
[SOURCE: IEC 61851-1:2017, 3.1.11]
3.41
case C
connection of an EV to the AC supply network utilizing a cable and vehicle connector permanently
attached to the EV charging station
[SOURCE: IEC 61851-1:2017, 3.1.12]
3.42
conductively connected circuit
two electric circuits are considered conductively connected unless they are separated by at least basic
insulation (3.4)
[SOURCE: ISO/TR 8713:2019, 3.26]
3.43
overload protection
protection intended to operate in the event of overload on the protected section
[SOURCE: IEC 60050-448:1995, 448-14-31]
3.44
overcurrent protection
protection intended to operate when the current is in excess of a predetermined value
[SOURCE: IEC 60050-448:1995, 448-14-26]
3.45
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
[SOURCE: IEC 61851-1:2017, 3.5.9]
3.46
propulsion system
combination of power source and powertrain for vehicle propulsion
[SOURCE: ISO 6469-2:2022, 3.12]
4 Abbreviated terms
AC alternating current (adjective)
a.c. alternating current (noun)
DC direct current (adjective)
d.c. direct current (noun)
rms root mean square
RESS rechargeable energy storage system
EV electrically propelled vehicle
DUT device under test
SPD surge protective device
RFI radio frequency interference
IEC International Electrotechnical Commission
ISO International Organization for Standardization
5 Voltage classes
Depending on its maximum working voltage U, an electric circuit, a section of a circuit or an electric
component belongs to the voltage classes specified in Table 1. Voltage class A is specified with maximum
working voltage of ≤30 V a.c. (rms) or ≤60 V d.c., respectively.
Voltage class B is specified with maximum working voltage between (> 30 and ≤ 1 000) V a.c. (rms) or (>
60 and ≤ 1 500) V d.c., respectively.
Table 1 — Voltage classes
Voltage class Maximum working voltage
V (DC) V (AC) (rms value)
A 0 < U ≤ 60 0 < U ≤ 30
B 60 < U ≤ 1 500 30 < U ≤ 1 000
NOTE The values 60 V d.c. and 30 V a.c. are selected taking into account humid weather
conditions.
6 General requirements
6.1 Environmental and operational conditions
The requirements given in this document shall be met across the range of environmental and
operational conditions for which the electrically propelled vehicle is designed to operate, as specified
by the vehicle manufacturer.
NOTE See the ISO 16750 series, ISO 21498-1 and the ISO 19453 series for guidance.
6.2 Marking
6.2.1 Marking of voltage class B electric components
The symbol ISO 7010–W012 shown in Figure 1 shall be visible on protective barriers and protective
enclosures, which, when removed, expose hazardous live parts of voltage class B electric circuits.
Accessibility and removability of protective barriers and protective enclosures should be considered
when evaluating the requirement for the symbol.
The symbol may be embossed or engraved in accordance with Figure 1. In this case colour is not
required.
For a protective enclosure consisting of several parts, one symbol is sufficient when visibility of the
symbol is given.
Figure 1 — Symbol ISO 7010–W012
6.2.2 Marking of voltage class B wiring
The outer covering of cables and harness for voltage class B electric circuits not within protective
enclosures or behind protective barriers shall be marked with orange colour.
Voltage class B connectors may be identified by the harnesses to which the connector is attached.
NOTE Specifications of the orange colour are given, for example in standards in the US (8.75R5.75/12.5) and
in Japan (8.8R5.8/12.5), according to the Munsell colour system.
7 Requirements for protection against electric shock
7.1 General requirements
7.1.1 General requirements for connected sections of a circuit
If not specified otherwise, an electric circuit consisting of conductively connected sections with
different maximum working voltages shall be classified according to the highest maximum working
voltage.
In case of electric circuits, that are conductively connected to each other, and fulfilling the specific
voltage condition, only the parts of the electric circuit that operate on voltage class B shall be classified
as a voltage class B circuit.
NOTE In the case above, parts of the electric circuit that operate on only voltage that is ≤ 30 V a.c. (rms) and
≤ 60 V DC are classified as a voltage class A circuit.
The electric chassis may be used as a conductor for the DC sections of a voltage class A electric circuit, if
the specific voltage condition is fulfilled.
The electric chassis shall not be used as a conductor for the AC sections of a voltage class B electric
circuit.
7.1.2 General requirements for voltage class B
Protection against electric shock for voltage class B shall be comprised of:
— provisions for basic protection; and
— provisions for fault protection.
The provisions for protection shall meet the requirements of 7.2 and 7.3. Provisions for fault protection
shall include combination of 7.3.1, 7.3.2, 7.3.3, and 7.3.6.
Compliance shall be tested according to test methods specified in Clause 11.
The provisions for electric cables and connectors, specified as a), b) and c) in 7.1.3.3, shall be applied.
7.1.3 Requirements for voltage class A
7.1.3.1 General requirements for voltage class A
Protection against electric shock for voltage class A shall be comprised of:
— limitation of voltage in accordance with Table 1.
At least functional insulation shall apply to live parts of voltage class A components or circuits to
prevent direct contact to live parts other than portion which are connected to electric chassis.
The protective measures required for voltage class B component and circuit may apply also to voltage
class A component or circuit.
7.1.3.2 General requirements of barrier and enclosures of voltage class A components
If a measure to prevent direct contact is provided by barriers and enclosures, live parts shall be placed
inside enclosures or behind barriers from any usual direction of access.
The barriers and enclosures shall provide sufficient mechanical strength under normal operating
conditions, as specified by the manufacturer.
7.1.3.3 Requirements for electric cables and connectors
The following provisions apply to voltage class A wirings.
a) Wire ways shall be smooth and free from sharp edges.
b) Wires shall be protected so that they do not come into contact with burrs, cooling fins or similar
sharp edges that may cause damage to their insulation. Holes in metal through which insulated
wires pass shall have smooth well-rounded surfaces or be provided with bushings.
c) Wiring shall be effectively prevented from coming into contact with moving parts.
Compliance with a), b), c) shall be checked by inspection.
d) If an open coil spring is used, it shall be correctly installed and insulated. Flexible metallic tubes
shall not cause damage to the insulation of the conductors contained within them.
Compliance with d) shall be checked by inspection.
e) The movable part is moved backwards and forwards, so that the conductor is flexed through the
largest angle permitted by its construction.
Compliance with e) shall be checked by the test described in 11.7.
f) The insulation of internal wiring shall withstand the electrical stress likely to occur in normal
use. Alternatively, the wiring shall not reduce the basic insulation adopted by the manufacturer or
the basic insulation shall be electrically equivalent to the basic insulation of cords complying with
IEC 60227-1 or IEC 60245-1.
Compliance with f) shall be checked by the test described in 11.7 or appropriate test for basic insulation.
7.1.4 Requirements of voltage class A power cables and conduits
Conduit entries, cable entries and knockouts shall be constructed or located so that the introduction of
the conduit or cable does not reduce the protective measures adopted by the manufacturer.
Compliance is checked by inspection.
7.2 Basic protection
The protective measures against direct contact shall be provided by either one or both of the following:
— basic insulation of the live parts;
— barriers and enclosures, preventing access to the live parts.
The protective measures of chassis-connected voltage class B electric circuit against direct contact,
shall be barriers and enclosures, preventing access to the live parts.
The protective provision in 7.4 shall apply.
7.3 Fault protection and additional measures
7.3.1 Equipotential bonding
Exposed conductive parts of voltage class B electric equipment that can be touched by a test finger
according to IPXXB (see ISO 20653) after removing all other parts that can be removed without using
tools, shall be bonded to the electric chassis to achieve equipotentiality.
All components forming the equipotential bonding current path (conductors, connections) shall
withstand the maximum current in a single fault condition.
The resistance of the equipotential bonding path between any two of these exposed conductive parts
of the voltage class B electric circuit that can be touched simultaneously by a person shall not exceed
0,1 Ω.
Compliance shall be tested in accordance with 11.2.
NOTE 1 Parts that are separated by a distance of more than 2,5 m are normally considered not to be
simultaneously accessible.
NOTE 2 Physical barriers are means to prevent simultaneous access to exposed conductive parts.
7.3.2 Isolation resistance
7.3.2.1 General
The isolation resistance requirement shall not apply to chassis-connected electric circuits.
The voltage class B electric circuits shall have sufficient isolation resistance.
The isolation resistance, divided by the maximum working voltage, shall have a minimum value of
100 Ω/V for DC circuits and a minimum value of 500 Ω/V for AC circuits.
NOTE According to IEC/TS 60479-1, body currents within zone DC-2 or zone AC-2 are not harmful. The
currents calculated from 100 Ω/V for DC and 500 Ω/V for a.c. are 10 mA and 2 mA respectively, and within these
zones.
To meet the above requirements for the entire circuit, it is necessary to provide a higher isolation
resistance for each component, depending on the number of the components and the structure of the
circuit to which they belong.
If DC and AC voltage class B electric circuits are conductively connected (see Figure 2), one of the
following two requirements shall be fulfilled for the conductively connected circuit:
— Option 1: isolation resistance, divided by the maximum working voltage, shall have a minimum
value of 500 Ω/V for the combined circuit;
— Option 2: isolation resistance, divided by the maximum working voltage, shall have a minimum
value of 100 Ω/V, if at least one of the alternative protective measures as specified in 7.3.4 is applied
to the AC circuit.
Compliance shall be tested in accordance with 11.3.
a) Option 1 b) Option 2
Key
1 fuel cell system
2 RESS
3 inverter
4 motor
5 vehicle electric chassis
6 partial isolation resistances
7 additional protection measures for AC circuit
NOTE The isolation resistance results from all partial isolation resistances “6” of the relevant electric
circuits.
Figure 2 — Isolation resistance - examples for conductively connected AC and DC circuits
7.3.2.2 Additional measures at a non-maintained isolation resistance
If the minimum isolation resistance requirement of a voltage class B circuit cannot be maintained
under all operational conditions and over the entire service life, one of the following measures shall be
applied.
— The isolation resistance shall be monitored periodically or continuously. An appropriate warning
shall be provided if the minimum isolation resistance requirement is violated. The voltage class B
circuit may be deactivated and de-energized (see 7.3.5) depending on the operational state of the
vehicle or the ability to activate the voltage class B circuit may be limited. The insulation resistance
monitoring system shall be tested in accordance with 11.4.
— Alternative protective measure according to 7.3.4.
NOTE 1 Isolation resistances below the required minimum values can occur due to deterioration of fuel cell
systems' cooling liquids or of certain battery types.
NOTE 2 If multiple isolation monitoring systems are applied for an electric circuit, their coordination is
considered.
NOTE 3 It is possible that de-energization is not applicable for the RESS.
7.3.3 Provisions for capacitive coupling and capacitive discharge
Capacitive coupling between the electric chassis and live parts of an electric circuit usually results from
Y capacitors, used for electromagnetic compatibility reasons, or from parasitic capacitive coupling.
The following applicable requirement shall apply to any individual voltage class B section of an electric
circuit which is not conductively connected to the electric chassis, if the touch current depends on
different operating conditions, e.g. working voltage, AC circuit, DC circuit.
NOTE 1 An AC section of a voltage class B electric circuit can possibly have a conductive connection to the
electric chassis through a different section of the same circuit.
If a touch current between a live part of a voltage class B electric circuit and electric chassis can occur
in case of a single failure, one of the following requirements shall apply:
— the stored electric energy between any energized voltage class B live part and the electric chassis
shall be <0,2 J and, after discharge, the touch current shall not exceed 5 mA for an AC circuit;
— alternative protective measures shall be followed according to 7.3.4.
NOTE 2 5 mA represents the threshold between AC-2 and AC-3 in IEC/TS 60479-1.
The relevant capacitance is the total capacitance resulting from all parallel capacitances between a
live part of a voltage class B electric circuit and the electric chassis. For the energy requirement the
maximum working voltage of a section of a circuit shall apply.
The requirement on the energy limit is deemed to be fulfilled, if the energy limit is confirmed by
calculation based on the designed capacitances of all related parts and components.
The touch current shall be measured according to 11.5.
7.3.4 Alternative electrical or mechanical measures
The following protective measures shall provide both basic protection and fault protection:
— double insulation;
— reinforced insulation;
— protective barriers in addition to the basic protection;
— protective enclosures in addition to the basic protection;
— conductive protective barrier with equipotential bonding in addition to basic insulation;
— conductive protective enclosure with equipotential bonding in addition to basic insulation;
— rigid protective barriers with sufficient mechanical robustness and durability over the vehicle
service life;
— rigid protective enclosures with sufficient mechanical robustness and durability, over the vehicle
service life.
The selected measure or combination of measures shall address the single failure for which it is
intended.
Different measures may be used for different sections of a circuit.
As the alternative protective measures, the following measure shall not be used for the chassis-
connected voltage class B electric circuits:
— conductive protective barrier with equipotential bonding in addition to basic insulation;
— conductive protective enclosure with equipotential bonding in addition to basic insulation.
The requirements for protective provisions in 7.4 shall apply.
7.3.5 De-energization
The voltage class B electric circuit in question may be de-energized as a protective measure. The
monitoring of faults within the circuit or the detection of events may be used to trigger the de-
energization. One of the following conditions shall be met for the de-energized circuit:
— the voltage shall be reduced to a value below 30 V a.c. (rms) and 60 V d.c.;
— the total stored energy of the circuit shall be <0,2 J,
— the touch current flowing between simultaneously accessible conductive parts shall not exceed
2 mA a.c. or 10 mA d.c.
The transition time and conditions to reach the de-energized state shall be specified by the manufacturer
in accordance with expected failures and vehicle operating conditions including driving.
7.3.6 Provision for chassis-connected voltage class B circuit
In case of a single-failure on the measure of basic protection, chassis-connected voltage class B electric
circuits shall meet alternative protective measures according to 7.3.4.
7.4 General requirements for protective provisions
7.4.1 General
All protective provisions shall be designed and constructed to be effective during the anticipated
lifetime of the vehicle when used as intended and properly maintained according to the vehicle
manufacturer´s specification.
7.4.2 Requirements for insulation of voltage class B
If protection is provided by insulation, the live parts of the electric system, electric circuit and
component shall be totally encapsulated by insulation which can be removed only by destruction.
The insulating material shall be suitable to the maximum working voltage and temperature ratings of
the vehicle and its systems.
Insulating varnish, dope, enamel, and other similar materials are not acceptable as basic insulation of
the voltage class B.
The insulation shall have sufficient withstand voltage capability. Compliance shall be tested according
to 11.6.
7.4.3 Requirements of protective barrier and protective enclosures of voltage class B electric
components
7.4.3.1 General
If protection is provided by protective barriers and protective enclosures, live parts shall be placed
inside protective enclosures or behind protective barriers, preventing access to the live parts from any
usual direction of access.
The protective barriers and protective enclosures shall provide sufficient mechanical resistance under
normal operating conditions, as specified by the manufacturer.
If protective barriers and protective enclosures are accessible directly, they shall be opened or removed
only by the use of tools or maintenance keys or they shall have means to deactivate
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