FAQ #358
Conductors > 150 mm for Precharge and Discharge

Last Updated On 12/8/2023 09:03:27 AM by

sayovitz

Question
Per EV.6.6.6, all reduced ampacity conductors branching off the TS high current path must be fused within 150mm of the source. However, EV.5.6.1 / EV.5.6.3 state that branched circuits related to the precharge & discharge circuits must not be fused.

We would like to clarify whether the intent of this rule is to create an exception from the overcurrent protection requirements for the aforementioned 2 circuits, or it should be interpreted as effectively limiting the pack side precharge lead & both discharge leads to <150mm.
Answer
EV.5.6.1.c and EV.5.6.3.c are NOT exceptions to EV.6.6.6. With that said, the precharge and discharge resistors can serve as the overcurrent protection if the conductors need to be longer than 150 mm.

For example, if you split the discharge resistance into two separate resistors (each half the total discharge resistance), and positioned one within 150 mm of TS+, and one within 150 mm of TS-, the total conductor length could be greater than 150 mm and the design would be in conformance with EV.6.6.6.
No Attachments
Rule Numbers
2024:EV.5.6.1 
2024:EV.5.6.3 
2024:EV.6.6.6