Test wires using magnets?

7dswinger said

There's a device that us electricians use that when you put it up against a wire it'll light up saying there's voltage running through the wire. Looks like a pen but bigger.

Click to expand...

I have one for AC power and it looks like a big fat Crayon. I think it came from one of the tool stores and was in a kit. It was really cheap. I don't know if mine would work on DC, I never thought about it but have.

Here is the AC version of it.
http://www.ebay.com/itm/AC-Non-Cont...296?pt=LH_DefaultDomain_0&hash=item43ae87a230