On Fri, 15 May 2009 20:48:20 -0700, "Richard W."
wrote:

I bought 3 4' shop light fixtures from Home Depot and when I plugged them
into a ground faulted line. They all tripped the ground fault. So I have
them sitting in the box not being used.

If you plugged them into a GFCI protected receptacle and they
tripped it, the light fixtures aren't necessarily bad - the normal
Class A GFCI receptacle is overly sensitive looking for 3 milliamps of
current imbalance and they trip.

If you paid less than $15 per fixture, it's very likely caused by a
crappy "Lowest Bidder" electronic ballast. The cheap electronic
ballasts that are not properly filtered can cause enough harmonics to
fool the GFCI currrent sensor and trip it. Doesn't take much.

First thing is to plug the strips into a regular outlet and confirm
that they do work. Then pop one open and see what the ballasts are
and that they do have the polarities correct.

You might have to go back to HD and get the better shoplight
fixtures, or run a seperate Non GFCI lighting circuit to the garage.
Tap off the existing garage ceiling light fixture and extend the
circuit with receptacles on the ceiling, that should be non GFCI.

Lights and dedicated appliance circuits (garage door opener, central
vacuum, freezers and refrigeration equipment, low-voltage lighting
transformers, sprinkler control timers) do not have to be GFCI
protected, only the convenience receptacles. You can either run
hardwired circuits to the appliances or place a single receptacle for
them without a GFCI in most cases.

Please don't use a cube tap into one of these single outlets to run
extension cords outside without a GFCI - they insist on them for a
reason, people do get zapped and occasionally killed.

-- Bruce --