BS ISO 6469-4:2015 pdf download – Electrically propelled road vehicles — Safety specifications Part 4: Post crash electrical safety
5.2.2 Voltage limit The voltages V b , V 1 , and V 2 (see Figure 1) of the voltage class B electric circuits shall be equal to or less than 30 V a.c. (rms) or 60 V d.c. at a point in time t m which is specified as
— either 10 s after the initial impact, if the vehicle comes to rest within 5 s after the initial impact, or
— 5 s after the vehicle comes to rest, if the vehicle does not come to rest within 5 s after the initial impact. Compliance shall be tested in accordance with 7.2.2.
5.2.3 Isolation resistance
5.2.3.1 General The isolation resistance shall fulfil the requirements according to 5.2.3.2 and 5.2.3.3. If direct contact to one potential of the voltage class B electric circuit is possible, the energy in Y-capacitors, TE y , as calculated in 7.2.5.2.2 shall be less than 0,2 J.
NOTE A potential body current caused by Y-capacitors is not limited by isolation resistance. The isolation resistance criterion shall not apply if direct contact to more than one single potential of a part of the voltage class B electric circuit is possible; see 5.2.4 (physical protection). However, isolation resistance criterion is applicable if the voltage difference between those accessible live parts meets the voltage limit specified in 5.2.2 or the potential energy between them meets the energy limit specified in 5.2.5. Compliance shall be tested in accordance with 7.2.3. If test procedures include a static rollover test after a crash, evaluation of isolation resistance can be conducted before, during, and/or after the rollover test.
5.2.3.2 Separated d.c. and a.c. voltage class B electric circuits If the a.c. voltage class B electric circuits and the d.c. voltage class B electric circuits are not conductively connected to each other, isolation resistance, divided by the maximum working voltage, shall have a minimum value of 100 Ω/V for d.c. circuits, and a minimum value of 500 Ω/V for a.c. circuits.
5.2.3.3 Combined d.c. and a.c. voltage class B electric circuits If the a.c. voltage class B electric circuits and the d.c. voltage class B electric circuits are conductively connected, they shall meet one of the following requirements:
a) isolation resistance, divided by the maximum working voltage, shall have a minimum value of 500 Ω/V;
b) isolation resistance, divided by the maximum working voltage, shall have a minimum value of 100 Ω/V and the a.c. circuit meets the physical protection as described in 5.2.4;
c) isolation resistance, divided by the maximum working voltage, shall have a minimum value of 100 Ω/V and the a.c. circuit meets the voltage limit as described in 5.2.2;
d) isolation resistance, divided by the maximum working voltage, shall have a minimum value of 100 Ω/V and the a.c. circuit meets the electrical energy limit as specified in 5.2.5.
5.2.4 Physical protection For protection against direct contact with voltage class B live parts, the protection degree IPXXB in accordance with ISO 20653 shall be provided. Compliance shall be tested in accordance with 7.2.4.1.
In addition, one of the following requirements [a) or b)] shall be fulfilled:
a) The potential equalisation paths intended by design shall be clarified in advance in accordance with the manufacturer’s specification, e.g. using diagrams, etc. The potential equalisation paths intended by design are the relevant electric connections or potential equalisation in accordance with ISO 6469-3 for the vehicle as built. The resistance between all exposed conductive parts and the electric chassis shall be less than or equal to 0,1 Ω. This requirement is deemed to be satisfied if the connection is established and maintained by welding. Compliance shall be tested in accordance with 7.2.4.2.
In addition, one of the following requirements shall be fulfilled.
— A short circuit current, if any, shall be interrupted.