I am starting to layout my 1st mains (90-260VAC 1Ph) PCB that will be fully encapsulated within epoxy potting compound (PX804C Flame Retardant 18kV/mm), and obviously this is a Class 1 device. Space will be limited, so I was wondering if the epoxy insulation will allow me to reduce the 8mm E-L/E-N Spacing? There is an exposed 'Earthed' Heat sink that will protrude through the epoxy, and low voltage terminals <32VDC. I do not have a issue with the mains to DC spacing, just the L/N/E spacing. Logic would tell me that the potting would act as a very good basic insulation, with little creepage possibility, so a much smaller spacing would be allowable. I cant specifically find this situation referenced, any advice would be greatly appreciated. Kind regards Jon

Edited: 15 February 2013 at 10:12 AM by jonrossmorgan

>8mm E-L/E-N Spacing

That's high - which standard are you using / what directives do you need to comply with?

Charlie

I used to work in Military with high pollution levels, but now I'm in commercial I suppose that level of isolation is not required.
I haven't got a copy of any regulations here, what standards should I be looking at for a normal commercial/domestic CE marked product?
( EN60065?)
As far as I can tell EN60065 requires 3mm spacing on class I, is this good enough? Bearing in mind there is no pollution and high dielectric insulation (potting)

Pick the most appropriate Harmonised Standard for your product from http://ec.europa.eu/enterprise...-voltage/index_en.htm

60065 would be correct standard for AV and similar equipment, alternatively 60950-1 could apply.

Cheapest, reputable, place for standards is Estonian Standards Centre: http://www.evs.ee/Esileht/tabi...ge/en-US/Default.aspx

I don't have a copy of 60065, and there are normally a few things that feed into the creepage/clearance requirements, but 3mm is in the right ball park.