I just finished wiring a new pole barn, the building will be used as a detached garage/workshop. An electrician friend helped me run power from the house to a new 100 amp panel in the barn and set the barn up with its own ground, isolating the grounding wires from the neutral and bonding the ground to the steel barn siding (not sure if that matters for this problem). I did the wiring inside the barn itself. Much of it was done before the panel was energized and was checked over by my friend. To be safe, I started all my circuits with a GFI with all other outlets downstream of the GFIs. The panel came with non-GFI breakers. My main lighting circuit wasnt in place yet, but was my next project once the power was in. That circuit has a couple of outlets next to the overhead doors, the first a GFI, then runs through a couple of 3-way switches placed by the overhead doors and the walk-through door so I can turn on the lights from either location. The wire runs from the second 3-way to two outlets in the rafters that I plugged fluorescent lights into and hung from chains. The problem I am having is that the GFI shuts off about 10 minutes after I turn on the lights. I can plug a load into either of the lower outlets with the lights off and have no trouble. Only the lights cut the circuit. If I switch the overhead outlets on, but leave the fluorescents unplugged there is no problem, but if I plug in any one of the three light fixtures and turn it on the probem comes back. If I disconnect the grounding wire to the overhead outlets the GFI doesn't cut out, but then the light fixtures aren't grounded. I suspect the light fixtures are "leaking" a small amount of current to ground. It's probably in the design of the fixtures, since any of the three fixtures will cut the GFI by itself. They aren't cheap fixtures, but better quality HO lamps designed to start immediately even at low temperatures. What is the best way to address this problem? I shouldn't leave the grounding wires disconnected, should I? The light fixtures hang about 10 feet above the concrete floor. Can I run a separate grounding wire back to the panel, or just to the barn siding, bypassing the GFIs grounding wire? Will that even solve the problem? Should I just wire the lighting circuit directly back to the panel and forget the GFI for that circuit?
|