Electronics > PCB/EDA/CAD

HV Resistor layout

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floobydust:
UL does care about insulation line-line in polyphase and a certifier can and will bridge any two points at their discretion inducing a fault.
Because it's not only the shock hazard they look for with insulation failure, it's the fire hazard as well from lack of a fuse or too big a branch feed.
Are the battery connections to the board fused? To what current? If an arc happens, you'd like it to clear voltage-sense fuse(s) and not burn up the board, car and garage/house.

EV HV DC bus is not chassis grounded, that I have seen. I believe the isolation was to give an extra level of protection against shock and confuse all mechanics until the end of time.
Although OP's resistors likely ruin that, there is a low value path. It might be a requirement we don't know. I'd expect an artificial 1/2 battery voltage to chassis ground.

There should not be the same transient overvoltages as seen from mains on the DC bus but I see no harm designing using the tried and true. It's a few extra mm.
Fluke multimeter rated 1,000V Cat. III design uses 8.5mm spacings and clever 4-layer traces. But applying 61010 to a vehicle? That's the loophole- I've seen a lot of automotive skirt safety standards because they are not a building/permanent installation apparently.

T3sl4co1l:
EV standards are probably a very new and active area of development, anyway... not that they're actually very new things, they've been around literally forever, just not to commercially significant levels -- what's new is the market shift, simultaneously towards lower production costs (better profits from quantity production) and to higher regulatory thresholds (partly for worker and user safety, or ostensibly so, but also as barriers to entry against new manufacturers!).

But that's just my assumption, that along with the increase in available onboard electrical power, also comes standards for working with them.

In any case, clearly there's no more than the usual automotive transients on the battery -- very different from nominal mains voltage plus category transients environment seen in traditional standards like 60950, 61010, etc.

And I wouldn't be surprised if the usual automotive transients indeed have to be modified, as for example the impulse from a battery contactor opening/closing under load (or into supply bypass caps, etc.) will be different levels from traditional relay or starter transients.

Tim

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