Mains Diode Bridge -Diode pad clearance?

[cupoftea]

Hi,
For a three diode bridge in 200-265VAC mains, (followed by smoothing cap) the diode may have up to 746V across it when off.
Please could you name the standard which governs the component packages that are acceptable here.?
Eg DO41 etc.
Is SMC acceptable to standards?
I appreciate it wont flash over, but ayk, "the standards is standards"

 

[dick_freebird]

Popcorn time

Looking into this for a couple-hundred-volt GaN driver I find the board processing as the big unknown. Free air creepage vs con-coat is a big deal and no way to know end user plans on a mass market part. I found no IC-packaging related guidelines, maybe because of the fog or maybe not knowing which rabbit-hole.

I imagine looking at Power Integrations packaging for a few in-range products would show you the "done thing" though not the "why, exactly -that-". But maybe there's app notes which offer their reasoning in more (than zero detail).