On Fri, 01 Feb 2013 10:21:13 -0800, pyotr filipivich wrote:

Jim Stewart on Thu, 31 Jan 2013 15:09:38 -0800
typed in rec.crafts.metalworking the following:
I've had one inch sparks from the belt to my hands while using it. Any
suggestions? It's chassis is connected to the power plug ground.

Dry air where you are working? - those could be"static"
electricity.

That's what it is ... charge builds up on the
outer surface of the belt, but the belt itself
is an insulator so the charge can't easily get
to ground until the voltage is high enough to
bore through the belt material.

The solution is to add a grounded metal brush
that just barely touches the belt. That'll drain
off the charge. If it doesn't ... well ... maybe
you're not as 'grounded' as you imagine. Get one
of those cheapo outlet testers.