Creepage and clearance question

Yes - the actual amount of non conductive material is what counts

Dan

Thanks Dan, that's what I thought, it would make sense!

Mark

Do you really have a connector that's rated below 75 volts pin-to-pin?

John

LV Directive stuff I should think.

No, the connector's fine but is on a 1mm pitch. It's the PCB I'm concerned about. The inter-gap spacing is around 0.4mm, given tolerances I'd like to increase it somewhat by using no-connects on the connector.

Mark.

Not this time! This is for an EL backlight circuit, the EL has to get to the PCB via a 1mm pitch FPC connector with several spare pins on it.

OK, skipping pins will certainly increase breakdown voltage, from maybe 3000 to maybe 6000.

John

Is it for a one-off, or production? If it's a one-off, I'd ask, is it possible to physically pull that middle pin out of the connector body?

If it's production, I'd say order some connectors with that pin not installed, maybe not even a hole there.

But, what do I know? The last time I saw anyone making connector headers, they were .025 pins on .1" centers. :-)

Cheers! Rich

Ask your PCB maker how small of a pad he can make - or don't even put a pad there at all, just the PTH, for the solder to stick to so it isn't flapping in the breeze - but just let them etch all the copper off around that hole.

Just an idea. :-)

Thanks! Rich

Hi John,

I guess you're suggesting that I've over-estimated the problem! Where did you get those breakdown figures BTW? I've always used *much* larger distances than that for PCBs. I'm looking for a minimum of Pollution Degree

Mark.

It's a surface mounted connector unfortunately but interesting idea anyway!

Mark.

I was guessing about *actual* breakdown voltages. UL seems to generally want 1 mm on a pc board, up to 85 volts (electronic test equipment), not too different from your numbers. If it's regulatory compliance, you've got to do it, but it's gross overkill in real life.

John

Just saw an ad for some AVX high-voltage ceramic caps. 2KV in a 1206 package, which, using our standard footprint, gives a pad-pad clearance of 52 mils, 1.3 mm!

John

On Thu, 20 Apr 2006 14:41:45 +0100, "markp" Gave us:

The Mfgr's spec on the connector will declare voltage isolation specs for you.

IEC 60065 or whatever standard may be more appropriate to your product.

Graham