ISO 6469-3:2021

INTERNATIONAL ISO
STANDARD 6469-3
Fourth edition
2021-10
Electrically propelled road vehicles —
Safety specifications —
Part 3:
Electrical safety
Véhicules routiers électriques — Spécifications de sécurité —
Partie 3: Sécurité électrique
Reference number
© ISO 2021
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ii
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Voltage classes .6
5 General requirements . 6
5.1 Environmental and operational requirements. 6
5.2 Marking . 7
5.2.1 Marking of voltage class B electric components . 7
5.2.2 Marking of voltage class B wiring . 7
6 Requirements for protection of persons against electric shock. 7
6.1 General requirements . 7
6.1.1 General requirements for connected sections of a circuit . 7
6.1.2 General requirements for voltage class B1 . 7
6.1.3 General requirements for voltage class B2 . 8
6.2 Basic protection . 8
6.3 Fault protection and additional measures . 8
6.3.1 Equipotential bonding . 8
6.3.2 Isolation resistance . 9
6.3.3 Provisions for capacitive coupling and capacitive discharge . 10
6.3.4 De-energization . 11
6.3.5 Alternative protection measures . 11
6.4 General requirements for protective provisions .12
6.4.1 General .12
6.4.2 Requirements for insulation .12
6.4.3 Requirements for protective barriers and protective enclosures .12
6.4.4 Requirements for connectors . 13
6.4.5 Insulation coordination. 13
6.5 Alternative approach for protection against electric shock .13
7 Protection against thermal incidents .13
7.1 Overload protection . 13
7.2 Short-circuit protection . .13
8 Requirements for vehicle power supply circuit .14
9 Owner's manual .14
10 Test procedures .14
10.1 General . 14
10.2 Continuity test for equipotential bonding . 14
10.3 Isolation resistance measurements for voltage class B2 electric circuits . 14
10.3.1 Preconditioning and conditioning . 14
10.3.2 Isolation resistance measurements of the balance of electric circuits.15
10.3.3 Isolation resistance measurement of the voltage class B2 electric power
sources .15
10.3.4 Isolation resistance measurement of entire electric circuits. 18
10.4 Test for isolation resistance monitoring system . 18
10.5 Touch current. 18
10.6 Withstand voltage test . 19
10.6.1 General . 19
10.6.2 Preconditioning and conditioning . 19
10.6.3 Test procedure. 19
10.6.4 Test criteria . 20
10.7 Withstand voltage test for electric power sources which are not de-energized .20
iii
10.7.1 General .20
10.7.2 Preconditioning and conditioning . 21
10.7.3 Test . . . 21
10.7.4 Test criteria . 23
Bibliography .24
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
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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
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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).
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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 37,
Electrically propelled vehicles.
This fourth edition cancels and replaces the third edition (ISO 6469-3:2018), which has been technically
revised. It also incorporates the Amendment ISO 6469-3:2018/Amd.1:2020.
The main changes are as follows:
— changes from ISO 6469-3:2018/Amd.1:2020 were implemented,
— requirements for equipotential bonding were revised.
A list of all parts in the ISO 6469 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 6469-3:2021(E)
Electrically propelled road vehicles — Safety
specifications —
Part 3:
Electrical safety
1 Scope
This document specifies electrical safety requirements for voltage class B electric circuits of electric
propulsion systems and conductively connected auxiliary electric systems of electrically propelled
road vehicles.
It specifies electrical safety requirements for protection of persons against electric shock and thermal
incidents.
It does not provide comprehensive safety information for manufacturing, maintenance and repair
personnel.
NOTE 1 Electrical safety requirements for post-crash are described in ISO 6469-4.
NOTE 2 Electrical safety requirements for conductive connections of electrically propelled road vehicles to an
external electric power supply are described in ISO 17409.
NOTE 3 Specific electrical safety requirements for magnetic field wireless power transfer between an external
electric power supply and an electrically propelled vehicle are described in ISO 19363.
NOTE 4 Electrical safety requirements for motorcycles and mopeds are described in the ISO 13063 series.
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 17409, Electrically propelled road vehicles — Conductive power transfer — Safety requirements
ISO 20653, Road vehicles — Degrees of protection (IP code) — Protection of electrical equipment against
foreign objects, water and access
IEC 60664 (all parts), Insulation coordination for equipment within low-voltage systems
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, that operates on electric energy
3.2
balance of electric circuit
remaining section of an electric circuit when all electric power sources (3.37) that are energized (3.16)
[e.g. RESS (3.31) and fuel cell stacks (3.20)] are disconnected
3.3
basic insulation
insulation of hazardous live parts (3.22) which provides basic protection (3.4)
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 (3.29) or protective enclosures (3.30) to prevent access to live parts in order to achieve basic protection.
[SOURCE: IEC 60050-195:2021, 195-06-06, modified — The phrase “hazardous live parts” and Note 2 to
entry were added.]
3.4
basic protection
protection against electric shock (3.14) under fault-free conditions
[SOURCE: IEC 60050-195:2021, 195-06-01, modified — The phrase “fault-free conditions” replaces
“normal conditions”.]
3.5
clearance
shortest distance in air between two conductive parts (3.6)
[SOURCE: IEC 60050-581:2008, 581-27-76]
3.6
conductive part
part which can carry electric current
[SOURCE: IEC 60050-195:2021, 195-01-06]
3.7
conductively connected
not separated by at least a provision for basic protection (3.4)
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/Amd.1:2013, 151-15-50]
3.9
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 phrases “or barriers” and “in accordance with
ISO 20653”, and the term IP were added.]
3.10
direct contact
electric contact of persons or animals with live parts (3.25)
[SOURCE: IEC 60050-195:2021, 195-06-03, modified — “persons” replaces “human beings” and
“animals” replaces “livestock”.]
3.11
double insulation
insulation comprising both basic insulation (3.3) and supplementary insulation (3.33)
[SOURCE: IEC 60050-195:2021, 195-06-08]
3.12
electric chassis
conductive parts (3.6) of a vehicle that are electrically connected and whose potential is taken as
reference
3.13
electric drive
combination of traction motor, power electronics and their associated controls for the conversion of
electric to mechanical power and vice versa
3.14
electric shock
physiological effect resulting from an electric current through a human body or animal body
[SOURCE: IEC 60050-195:2021, 195-01-04, modified —“animal body” replaces “livestock”.]
3.15
electrically propelled vehicle
vehicle with one or more electric drive(s) (3.13) for vehicle propulsion
3.16
energized
live
at an electric potential different from that of electric chassis (3.12) at the worksite and which presents
an electrical hazard
Note 1 to entry: A part is energized when it is electrically connected to a source of electric energy. It can also be
energized when it is electrically charged and/or under the influence of an electric or magnetic field.
[SOURCE: IEC 60050-651:2014, 651-21-08, modified — “electric chassis” replaces “earth” and the Note
2 to entry was deleted.]
3.17
equipotential bonding
provision of electric connections between conductive parts (3.6), intended to achieve equipotentiality
[SOURCE: IEC 60050-195:2021, 195-01-10, modified — “provision” replaces “set”.]
3.18
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 (3.3) 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, modified — “equipment” replaces “electric equipment”.]
3.19
fault protection
protection against electric shock (3.14) under single-fault conditions
[SOURCE: IEC 60050-195:2021, 195-06-02]
3.20
fuel cell stack
assembly of two or more fuel cells that are electrically connected
3.21
fuel cell system
system, typically containing the following subsystems: fuel cell stack (3.20), air processing, fuel
processing, thermal management, water management, and their control
3.22
hazardous live part
live part (3.25) which, under certain conditions, can give a harmful electric shock (3.14)
Note 1 to entry: For guidance on harmful physiological effects see IEC 61140.
[SOURCE: IEC 60050-195:2021, 195-06-05, modified — Term changed from “hazardous-live-part” to
“hazardous live part” and Note 1 to entry was added.]
3.23
isolation resistance
insulation resistance
resistance between live parts (3.25) of an electric circuit and the electric chassis (3.12) as well as other
electric circuits which are insulated from this electric circuit
3.24
isolation resistance monitoring system
system that periodically or continuously monitors the isolation resistance (3.23) between live parts
(3.25) and the electric chassis (3.12)
3.25
live part
conductor or conductive part (3.6) intended to be energized (3.16) in normal use, but by convention not
the electric chassis (3.12)
3.26
maximum working voltage
highest value of AC voltage (rms) or of DC voltage that can occur under any normal operating conditions
according to the manufacturer's specifications, disregarding transients and ripple
3.27
overload protection
protection intended to operate in the event of overload on the protected section
[SOURCE: IEC 60050-448:1995, 448-14-31]
3.28
overcurrent protection
protection intended to operate when the current is in excess of a predetermined value
[SOURCE: IEC 60050-448:1995, 448-14-26]
3.29
protective barrier
part providing protection against direct contact (3.10) from any usual direction of access
[SOURCE: IEC 60050-195:2021, 195-06-15, modified — “against direct contact” replaces “against
contact by a human being or livestock with hazardous-live-parts” .]
3.30
protective enclosure
electrical enclosure surrounding internal parts of equipment to prevent access to hazardous live parts
(3.22) from any direction
[SOURCE: IEC 60050-195:2021, 195-06-14]
3.31
RESS
rechargeable energy storage system
rechargeable system that stores energy for delivery of electric energy for the electric drive (3.13)
EXAMPLE Battery, capacitor, flywheel.
3.32
reinforced insulation
insulation of hazardous live parts (3.22) which provides protection against electric shock (3.14)
equivalent to double insulation (3.11)
Note 1 to entry: Reinforced insulation may comprise several layers that cannot be tested singly as basic insulation
(3.3) or supplementary insulation (3.33).
[SOURCE: IEC 60050-581:2008, 581-21-27]
3.33
supplementary insulation
independent insulation applied in addition to basic insulation (3.3), for fault protection (3.19)
[SOURCE: IEC 60050-195:2021, 195-06-07]
3.34
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”.]
3.35
vehicle power supply circuit
voltage class (3.36) B electric circuit which includes all parts that are conductively connected (3.7) to
the vehicle inlet (case B, case C) or the plug (case A) or part of an autoconnect charging device that
is mounted on the electrically propelled vehicle (3.15) (case D, case E) and that is operational when
connected to an external electric power supply
Note 1 to entry: Case A, case B, case C are defined in IEC 61851-1.
1)
Note 2 to entry: Case D, case E and autoconnect charging device are defined in IEC 61851-23–1 .
[SOURCE: ISO 17409:2020, 3.61, modified — Note 1 to entry replaced and Note 2 to entry added.]
3.36
voltage class
classification of an electric component or circuit according to its maximum working voltage (3.26)
1) Under preparation. Stage at the time of publication: IEC/PRVC 61851-23-1:2021.
3.37
electric power source
system that provides electric energy
EXAMPLE RESS (3.31), fuel cell system (3.21), photovoltaic system.
4 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.
Table 1 — Voltage classes
Maximum working voltage
Voltage class
DC in V AC in V (rms value)
A 0 < U ≤ 60 0 < U ≤ 30
B 60 < U ≤ 1 500 30 < U ≤ 1 000
B1 60 < U ≤ 75 30 < U ≤ 50
B2 75 < U ≤ 1 500 50 < U ≤ 1 000
The voltage classes B1 and B2 are subclasses of voltage class B. Due to the different voltage levels,
different requirements are specified for voltage class B1 and voltage class B2, whereas the requirements
for voltage class B2 are more stringent. The requirements for voltage class B2 may be applied for the
complete range of voltage class B, including the voltage range of voltage class B1. It is allowed to use
voltage class B instead of voltage class B1 and voltage class B2.
In cases where voltage class B is referenced by another standard, the requirements for voltage class B2
apply.
NOTE 1 Dividing voltage class B into two voltage classes B1 and B2 allows chassis-connected voltage class
B1 drivetrain and connected electrical systems in electric vehicles according to the given scope. Otherwise,
all circuits which contain AC sections with a maximum working voltage between 30 V AC and 50 V AC, and DC
sections with a maximum working voltage up to 60 V DC, would have to be insulated from the chassis, only
because the AC part of the circuit falls into voltage class B range, whereas it would be possible for the DC part to
still fall under the regulations for a voltage class A circuit.
NOTE 2 If the requirements of voltage class B1 are fulfilled, the maximum working voltage of an electric
circuit, a section of a circuit or an electric component can be up to 75 V DC and up to 50 V AC.
NOTE 3 The requirements for voltage class B1 are based on IEC 61140, IEC 60479-1, IEC 60479-2, IEC 60479-5,
and IEC 60364-4–41.
NOTE 4 The voltage limits of voltage class B1 are harmonized with the European Low Voltage Directive and
IEC 61140 (the AC limit). Electric vehicles are not in the scope of the European Low Voltage Directive.
5 General requirements
5.1 Environmental and operational requirements
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.
5.2 Marking
5.2.1 Marking of voltage class B electric components
The symbol ISO 7010–W012 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 — ISO 7010-W012 - Warning; Electricity
5.2.2 Marking of voltage class B wiring
The outer covering of cables and harness for voltage class B2 electric circuits not within protective
enclosures or behind protective barriers shall be marked with orange colour. Voltage class B1 cables
and harness shall be marked with a two-colour combination of orange and purple or with orange colour.
In case of the two-colour combination, each colour shall cover at least 30 % of the surface. The marking
shall be visible over the whole cable length and from all usual directions of access.
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.
6 Requirements for protection of persons against electric shock
6.1 General requirements
6.1.1 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.
6.1.2 General requirements for voltage class B1
Protection against electric shock for voltage class B1 shall be comprising:
— limitation of voltage in accordance with Table 1 under normal conditions;
— provisions for basic protection according to 6.2; and
— additional measures according to 6.3.1 and 6.3.3.
The electric chassis may be used as a conductor for the DC sections of a voltage class B1 electric circuit.
The electric chassis shall not be used as a conductor for the AC sections of a voltage class B1 electric
circuit.
An electric circuit may consist of sections with voltage class B1 and sections with voltage class A. In
this case the following conditions shall apply.
— At a single fault in this circuit the voltage of the voltage class A sections shall not exceed the limits
specified for voltage class A.
— The voltage class A sections shall be classified as voltage class A.
NOTE A failure of an electronic switch is an example for a single fault.
6.1.3 General requirements for voltage class B2
Protection against electric shock for voltage class B2 shall be comprising:
— provisions for basic protection according to 6.2; and
— provisions for fault protection according to 6.3.
The provisions for protection shall meet the requirements as described in 6.2. and 6.3.
Provisions for fault protection shall include 6.3.1, 6.3.2 and 6.3.3.
6.2 Basic protection
For basic protection, the requirement of basic insulation shall be fulfilled.
The protective provisions in 6.4 shall apply.
Different measures to provide basic protection may be used for different sections of a circuit.
6.3 Fault protection and additional measures
6.3.1 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 shall withstand the maximum current
it will be exposed to in the event of a single insulation fault between a voltage class B live part and an
exposed conductive part or between a voltage class B live part and the equipotential bonding current
path.
If de-energization in case of such a single insulation fault is not implemented, provisions shall be taken
to avoid risk of harmful electric shock in the event of two insulation faults, each between a voltage class
B live part and an exposed conductive part or between a voltage class B live part and the equipotential
bonding current path, existing simultaneously.
NOTE 1 The fault current originated from an insulated voltage class B electric circuit (i.e. a voltage class B2
electric circuit or a voltage class B1 electric circuit which is not conductively connected to the electrical chassis)
is low in the event of such a fault and de-energization is not imperative.
EXAMPLE 1 The equipotential bonding current path is designed to withstand a short-circuit current until de-
energization is achieved.
EXAMPLE 2 The isolation monitoring according to 6.3.2.2 is used to deactivate and de-energize (see 6.3.4) the
voltage class B2 system depending on the operational state of the vehicle and the ability to activate the voltage
class B2 system is limited if the minimum isolation resistance requirement is violated.
NOTE 2 Currents caused by electromagnetic interference (EMI) and currents from voltage class A and voltage
class B1 systems using the equipotential bonding path as a conductor contribute to the maximum current
through the equipotential bonding current path.
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.
Conformance shall be tested in accordance with 10.2.
NOTE 3 Parts that are separated by a distance of more than 2,5 m are normally considered not to be
simultaneously accessible.
NOTE 4 A physical barriers is a means that can prevent simultaneous access to exposed conductive parts.
6.3.2 Isolation resistance
6.3.2.1 General
The voltage class B2 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 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 AC are 10 mA and 2 mA respectively, and within these zones.
To meet the above requirement 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 B2 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 protection measures as specified in 6.3.5 is applied
to the AC circuit.
Conformance shall be tested in accordance with 10.3.
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
6.3.2.2 Additional measures at a non-maintained isolation resistance
If the minimum isolation resistance requirement of a voltage class B2 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 B2
circuit may be deactivated and de-energized (see 6.3.4) depending on the operational state of the
vehicle or the ability to activate the voltage class B2 circuit may be limited. The insulation resistance
monitoring system shall be tested in accordance with 10.4.
— Alternative protection measure according to 6.3.5.
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 De-energization is not applicable for the RESS.
6.3.3 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 requirements apply to:
— any section of a voltage class B2 electric circuit individually, if the touch current depends on different
operating conditions, e.g. working voltage, AC circuit, DC circuit; and
— an AC section of a voltage class B1 electric circuit which is not conductively connected to the electric
chassis.
NOTE 1 It is possible that an AC section of a voltage class B1 electric circuit has 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 of this stored energy, the touch current shall not exceed 5 mA for
an AC circuit and 25 mA for an DC circuit.
— Alternative protection measure according to 6.3.5.
NOTE 2 5 mA represents the threshold between AC-2 and AC-3 in IEC 60479-1 and 25 mA represents the
threshold between DC-2 and DC-3.
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 10.5.
6.3.4 De-energization
The voltage class B2 electric circuit in question may be de-energized as a protection 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 50 V AC and 75 V DC;
— the total stored energy of the circuit shall be < 0,2 J and
the touch current flowing between simultaneously accessible conductive parts shall not exceed
5 mA AC or 25 mA DC.
NOTE 5 mA represents the threshold between AC-2 and AC-3 in IEC 60479-1 and 25 mA represents the
threshold between DC-2 and DC-3.
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.
6.3.5 Alternative protection measures
The following 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; and
— 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 fault for which it is intended.
Different measures may be used for different sections of a circuit.
The requirements for protective provisions in 6.4 shall apply.
6.4 General requirements for protective provisions
6.4.1 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.
6.4.2 Requirements for insulation
The following requirements apply to basic insulation, double insulation and reinforced insulation.
Insulation shall fulfil the specific requirements related to basic insulation, double insulation or
reinforced insulation in accordance with 6.4.5.
Insulation can be a solid, a liquid or a gas (e.g. air), or any combination.
Where insulation is not provided by solid insulation only, access to live parts shall be prevented by
protective barriers or protective enclosures according to 6.4.3.
Live parts of cables not within protective enclosures or behind protective barriers shall be totally
encapsulated by solid insulation that can be removed only by destruction.
6.4.3 Requirements for protective barriers and protective enclosures
6.4.3.1 General
Protective barriers and protective enclosures shall have sufficient mechanical strength, stability
and durability to maintain the specified provisions of protection, taking into account all relevant
environmental conditions.
It shall not be possible to open or remove protective barriers and protective enclosures without the use
of tools or they shall have means to de-energize voltage class B live parts according to 6.4.4 c).
The protective barriers and protective enclosures may be electrically conductive or provided by solid
insulation.
6.4.3.2 Degree of protection for protective barriers and protective enclosures
Protective barriers and protective enclosures shall comply with the degree of protection IPXXB at a
minimum.
Protective barriers and protective enclosures in passenger and load compartments shall comply with
the degree of protection IPXXD at a minimum.
Conformance shall be tested in accordance with ISO 20653.
6.4.4 Requirements for connectors
Connectors for voltage class B electric circuits shall comply with 6.4.3.2 in the mated condition.
Connectors for voltage class B electric circuits including vehicle inlet (in case B or C according
to IEC 61851-1) or the plug (in case A according to IEC 61851-1) and including the contacts of an
autoconnect charging device (case D and E according to IEC 61851-23-1) shall comply with at least one
of the following requirements.
a) A connector shall comply with 6.4.3.2 in the unmated condition.
b) It shall not be possible to unmate a connector without the use of tools. This requirement is deemed
to be fulfilled by placing a connector behind a protective barrier or inside a protective enclosure.
c) Voltage class B live parts of a connector shall be de-energized when it is unmated. One of the following
conditions shall be met for the de-energized live parts:
— the voltage shall be reduced to a value below 30 V AC and 60 V DC;
— the total stored energy of the circuit shall be ≤ 0,2 J and the touch current flowing
between simultaneously accessible conductive parts shall not exceed 2 mA AC or 10 mA DC
Conformance shall be tested according to 10.5 or demonstrated by calculation.
NOTE 2 mA AC touch current aligns with an isolation resistance of 500 Ohm/V. 10 mA DC touch current
aligns with an isolation resistance of 100 Ohm/V.
6.4.5 Insulation coordination
Clearance, creepage distance and solid insulation of voltage class B components and wiring shall be
designed according to the applicable sections of the IEC 60664 series.
A different approach may be used if it provides equivalent safety.
Voltage class B circuits not conductively connected to the electric chassis shall be tested according to
10.6.
6.5 Alternative approach for protection against electric shock
As an alternative to 6.3, the vehicle manufacturer shall conduct an appropriate hazard analysis and
establish a set of measures which give sufficient protection against electric shock under single fault
conditions.
7 Protection against thermal incidents
7.1 Overload protection
Overload protection shall be provided fo
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