Spacing between AC mains traces on pcb?

"Air is a pretty good insulator."

Unfortunately, tracking across the surface of a printed circuit board is a different problem, and cutting slots is expensive.

---------- Bill Sloman, Nijmegen

The UL standard books relevant to what application this is .. and whether this is "Safety Insulation" or merely "Insulation" ?? (There are several UL standards, I have an "Office/Indoor" somewhere on Paper, "Industrial" would be different, e.t.c.).

What did Google say about whatever Standard Institute applicable to your part of the world?

Google, as usual, said way too much that had nothing to do with it no matter how I refined the search. Is it me, or is google now so overinflated it is useless?. I feel like a guy trying to use a million pimps for some serious research. I went to a clients yesterday and read UL 840, that spelled it out pretty well. If you know the environment rating and the material (air, and PCB) you can find a number. This ranged from 40 to 157 mils depending on environmental conditions. I decided my client should try for 100 mils, or as close as they can get between the raw ac mains, that will allow them to pass with flying colors if they get a 2 or 3 environment rating, and that is what I expect.

Rocky

Google was a snap.

external conductor, uncoated, sea level to 10000ft

found at

and at

Al