Eric in North TX wrote:
picture this.

I'm crouched on the living room floor using my good old metal bodied
electric drill with it's three prong plug in my right hand and my left
arm is braced against a radiator.

I drill through the sheetrock and hit the wire behind it going to the
laundry dryer's 240 V receptical. I'd get zapped, and that ungrounded
GFCI outlet my drill was plugged into wouldn't even know it. If there
was a real ground connected to that receptical, The dryer's breaker
would trip, and I'd still be breathing.


Some how I doubt it would make a lot of difference if you had the
drill plugged into a ground fault if you nail a 240 volt line with a
metal drill while touching a radiator. It's like; oh good the drill
power supply disconnected, now I only have my body stuck between the
power station and the radiator to worry about zzza-zzza-zzza zap pow,
wish I didn't have a pacemaker. zzza-zzza-zzza, zzza-zzza-zzza
zapzapzap, thank god I was plugged into a ground fault zzza-zzza-zzza,
zzza-zzza-zzza zapzapzap.


That's eggzactly the point I was making. If the ground pin on the
drill's power cord was plugged into a receptical whose ground pin was
REALLY connected to ground then.....

When the drill bit touched the live wire (only 120 volts to ground, not
240 BTW.) the drill's body would NOT elevste to that voltage, and the
short circuit would cause an overcurrent trip of the breaker feeding
that 240 volt line. Well, the drill body might rise a couple of volts
off ground during the moment it took for the 240 volt line's breaker to
pop, but probably not high enough to even be felt.

But, if the receptical my drill was plugged into had a ground hole which
WASN'T connected to ground, then I'd get fried, whether or not it was a
GFCI type receptical. The GFCI wouldn't trip because the drill bit
hitting the wire does not create a path to ground from the GFCI's hot or
neutral outputs. I described the drill bit hitting a 240 volt laundry
dryer feed just to eliminate it from being a downstream 120 volt
conductor from the output side of the GFCI receptical. If it was, then
the GFCI would trip and save my ass.

Capice?

Jeff

--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
"What do you expect from a pig but a grunt?"