1. Clearances for US Safety: I'd cite the relevant standards, but they are so alike (identical Clearance tables), and so alike to UL 508, I'll defer. Here's the question: When citing clearance spacing from "uninsulated live components" does one measure from the edge of a PCB to the enclosure well, or only from the live components, like a pad, or the bottom pin of a thru-hole cap?1a. what sort of passivation or RTV could make those live components not "uninsulated"? 2. Slots to increase creepage for high-voltage components A FET that's rated for say 600V does not have to follow PCB-creepage rules for 600V, is clearly stated places like UL 1741, ยง26.1.1 exception #8. For other components, like say 1000V caps in 0805 packages or FET driver chips the requirements aren't as clear. Is a slot needed to maintain creepage or not if the component is properly rated? It does appear from a TI support page for dual-bridge converters, that slots are recommended in order to prevent contamination that may compromise the components isolation performance. My gut says: no, slots are not needed between component terminals on a PCB, but could be recommended for sensitive parts, like FET drivers. Thoughts? Colorado Brian
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