# Typical max voltage for a typical protoboard

#### jaydnul

Joined Apr 2, 2015
163
For a typical protoboard like this one

about how high does the voltage need to get across two neighboring pads before they spark across?

I am afraid of connecting my 20V power supply across two neighboring pads for fear of discharge but I can't find any info on the protoboard's datasheet.

Thanks

#### tindel

Joined Sep 16, 2012
933

#### wayneh

Joined Sep 9, 2010
17,405
I agree that 20V is no concern. I'd begin to wonder at maybe 100V or more.

#### crutschow

Joined Mar 14, 2008
32,848

#### wayneh

Joined Sep 9, 2010
17,405
My boards have a pad spacing of 0.1", and adjacent pads come within ~0.9mm (0.036") of each other (0.036"). According to the reference provided by above by @crutschow, that allows for a voltage difference of >150V, maybe up to 160V or so.

That's plenty for most stuff but it does tell me that rectified AC at ~170V would not be a good idea. That fits my hunch that getting over 100V warrants looking into the details.

#### jaydnul

Joined Apr 2, 2015
163
K cool, thanks everyone!

#### ErnieM

Joined Apr 24, 2011
8,362
My boards have a pad spacing of 0.1", and adjacent pads come within ~0.9mm (0.036") of each other (0.036"). According to the reference provided by above by @crutschow, that allows for a voltage difference of >150V, maybe up to 160V or so.

That's plenty for most stuff but it does tell me that rectified AC at ~170V would not be a good idea. That fits my hunch that getting over 100V warrants looking into the details.
What you are assuming is the voltage is across two adjacent pads.

If you skip a row you get not 150 V but 300 volt iolation, and you can keep skipping rows till your sleep at night remains undisturbed.

#### wayneh

Joined Sep 9, 2010
17,405
Yeah, putting even 12V onto two adjacent pads makes me nervous. It's so easy to get a whisker of solder or a bent component lead or whatever. Those don't really seem to happen but I prefer not temp fate.