I have a question about pcb trace spacing. What trace spacing should I use on my pcb for 12v signals. Nominally it should be a few mils minimum for a peak voltage of 15v on an outer layer. My question is in an automotive application, there could be short transient spikes of 100v due to load dumping on the 12v trace. Do I have to space them for 100v peak?
for more safty you can use 5mil spasing for 100v
but you can use spasing smaller that it becouse 100v is not continuas (DC) it is just brust for small time you can avarege pulse power over it's time to
it is unusual to find a cheap manufacturer that can do less than 6 thou with any reliability. I would stick with 8 thou gaps and have the extra assurance.