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GFI and switch contolling two florescent fixtures not working

GFI and switch contolling two florescent fixtures not working


Old 08-31-00, 10:31 AM
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I am wiring two florescent fixtures (four 40 watt bulbs each) with a silent glow switch and GFI. When I turn on the switch it trips the GFI. I had the florescent fixtures temporarily wired to an older basement circuit for two months, so I know they are wired correctly.

To keep from having all 10 lights in my basement on at one time, I added a brand new circuit to by circuit breaker box. I first wired the new circuit to a GFI outlet to protect the second outlet and switch on the circuit (all components are new). The second outlet is correctly connected to the load side of the GFI. I tested the GFI and second outlet with a receptacle & GFI tester and everything tested OK.

From the second outlet, I wired the black wire (brass terminal) to the in terminal on the switch. Then I wired the out terminal on the switch to the black wire going to the florescent fixtures. I next wired the white wire coming from the florescent fixtures to the neutral side (silver terminal) of the second outlet. The bare ground wire is connected to the GFI, second outlet, switch and florescent fixtues.

I thought this wiring was correct, but when I flip the switch it trips the GFI. I replaced the switch with a new one and I get the same problem. Do you know where I went wrong?

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Old 08-31-00, 05:02 PM
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YOu have a hard one to diagnose let alone explain. I might attempt to answer your question with some knowledge involved in how a gfi works and how a light fixture works. You did not explain wheather the light fixtures were rapid start or HO type. I suspect your gfi is registering a current between the grounded white and the grounding green or bare.
A gfi will kick if the bare wire and the white wire make contact in any manner. The gfi will kick if any current registers on the grounding conductor green or bare.
A flourescent fixture has a ballast that ignites the gases in the tubes in order to produce light. The flourescent fixture relies on the grounding conductor green or bare to excite the tube during ignition of their gases. The hot and the white grounded conductor completes the circuit to maintain the ignited gases of the light.
The receptacles in a basement are required to be gfi protected unless found behind a large appliance and on a single outlet not a duplex outlet.
The lighting in the basement are not required to be gfi protected.
The gfi seems to be sensitive to the momentary current on the bare or green grounding conductor experienced during the ignition of the gases of the flourescent tubes.
I suggest that you power your light switch and flourescent fixtures from the line side of the gfi receptacle if you are using a receptacle style gfi control. This would keep the gfi from reacting from this impedance during the ignition of the gases in the light fixtures.
If you are using a breaker style gfi, I suggest that you return the breaker style gfi and install a receptacle style so that you can get the load of the flourescent fixtures off of the load side of the gfi by connecting to the line side of the gfi receptacle control.
Please remember to maintain gfi protection on you basement receptacles as required by the minimum safety standards.

Good luck

Old 08-31-00, 08:26 PM
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They are rapid start. Each fixture has two ballasts. I am using a receptacle style 20 Amp GFI. Thanks for your response. I will try your suggestions this week-end.

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