On Mon, 4 Feb 2013 13:49:40 -0800 (PST), DerbyDad03
wrote:

A couple of years ago I built a shed and ran power to it through some
underground PVC conduit. Power to the shed is sourced from a GFCI
receptacle under my deck. The shed has an interior light fixture, an
external receptacle and an external motion sensor light fixture.

Last week I noticed that the motion sensor fixture was not turning on
so I went out to the shed and found that the GFCI receptacle had
tripped. I reset the GFCI, both lights came on and seconds later the
GFCI tripped again. I turned off the disconnect switch in the shed,
reset the GFCI and it stayed on. Flipped on the disconnect and the
GFCI tripped.

Satisfied that (thankfully) it did not appear to be my underground
wiring, I opened the junction box for the motion sensor fixture and
disconnected it. When I reset the GFCI it stayed on. OK, problem
found.

I took the Made In China light fixture - which was clearly marked "For
External Use" - off of the shed and into the workshop. I opened the
bulb housing and saw water around the wires that went to the bulb
socket. I guess it's "For External Use" in dry locations only. The
best I can tell is that the water got in through the ball and socket
joint that allows you to aim the light.

I let the unit dry out and then filled the tube from the ball and
socket joint to the light socket with silicone so the water can't
reach the socket. I remounted it, aimed the light and then put some
more silicon around the exterior of the ball and socket joint to
hopefully prevent water from entering the fixture in the first place.

Piece of crap Chinese fixture. Maybe the GFCI was made in China also,
but at least it works the way it is supposed to.

I've believed that GFCI's work or don't work. I think two
(pool/garage) act funny during a reset.

The garage trips occasionally as it is also a bathroom circuit. It
trips if a hairdryer is used when I have something plugged in with a
higher amp draw? Lately, it tripped a few times. When I try to reset
it would not, but a little force on the reset button it did. The
thing "chattered" as I reset it.

I'll be replacing both the garage and the one for the pool light -
real soon (next trip to the Borg).

(something tripped at the Super Bowl G)