Dan Lanciani wrote:
In article , zzzzzzzzzz ) writes:
| On Sat, 12 Mar 2011 13:52:58 -0800, David Nebenzahl
| wrote:
|
| Just a li'l anecdote for those who've always wondered what happens if
| you wire a GFCI to protect "downstream" outlets wrong (all 2 of
| you)--that is, if you mix up the "line" and "load" wires.
|
| The answer? Nothing.
|
| Installed a GFCI in a client's kitchen, thinking I'd need two, one for
| each outlet on a sink counter. It became clear, though, that they were
| in a chain, so I could protect both with just one GFCI. So I wired in
| the GFCI, wiring the downstream outlet on the "load" side, ass-u-ming
| that the position of the cables in the box indicated the upstream and
| downstream wiring respectively.
|
| Wrong.
|
| When I turned on the power, the GFCI's LED lit, but I couldn't reset the
| outlet, and both outlets were dead.
|
| Strange, when I made the same mistake the outlets worked normally but wouldn't
| trip on a "downstream" fault. The differential current sensing was on the
| wrong side of the device, so didn't detect the fault. I can't see how they'd
| fail the way you suggest.
Newer GFCIs are specifically designed to be idiot-proof in this respect.
They aren't failing; they are just helping you. 
Although older GFCIs
would not be damaged by the incorrect wiring, they wouldn't be able to
shut off the power to the local outlet even if they trip.
Dan Lanciani
ddl@danlan.*com
I agree.
Older GFCIs had the load terminals connected to the receptacle. If
connected line-load reversed the receptacle was always powered and a
ground fault on the receptacle would not trip the GFCI. The test button
would trip the GFCI but the outlet was still hot. Anything connected
downstream would be protected as intended. Instructions are likely to
say to connect a lamp and push the test button - make sure the lamp goes
out.
A while ago the UL standards changed. Now if a GFCI trips, the
receptacle is not connected to the line or load terminals. The internal
electronics are probably connected to the receptacle. If these GFCI
receptacles are "set" and installed with line-load reversed they
shouldn't detect a ground fault on the receptacle. Downstream protects
as intended. If you push the test button the GFCI trips and can not be
reset. They are intentionally shipped in the tripped condition, so if a
new GFCI is installed line-load reversed it can not be reset.
--
bud--