ISO 6469-3:2021 pdf download – Electrically propelled road vehicles — Safety specifications — Part 3: Electrical safety.
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]
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.