Ground fault protection for fan/light
alhimprov
| Posted in Construction Techniques on
I’m doing work for a customer who is moving. Inspector said that fan/light combo in bathroom needs to be protected on ground fault circuit because it is above shower. The fan/light combo is on its own circuit. The homeowner installed a GFI circuit breaker, but when they turn the light or fan on it trips the breaker immediately. The power comes from the panel to the switch and then to the fan unit. What is the proper way to protect the circuit and eliminate the breaker tripping?
Replies
A WAG says the breaker or something in the circut isn't wired correctly...
The GFI breaker is the way to go in this case.
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The fixture should be listed for "wet locations". Doing work and not meeting min. code leaves you open to liability.
I'm going to guess that two circuits in that bathroom are coming in on a single piece of 12/3 wire. Open everything up and see if you find a red wire somewhere. If so, that may be an issue. I'm not really sure, just having a flashback to something we had to troubleshoot once upon a time. In our bathroom here the fan is fed from a GFCI. Sometimes turning it off trips the GFCI. An electrician with a solid grasp of how stuff works could explain it...
Are you legally allowed to do electrical work in a clients home without being an electrician? Just wondering because where I live it is not allowed at all, besides the liability issues!
It does sound like a simple circuit that has been miswired if it's tripping the breaker, maybe time for an electrician?
Discounting a defective GFI, I assume it is new and properly hooked up as it doesn't trip without the fan or light on and turning on the fan or light consistently trips it, it seems to be a local wiring issue. Possibly a defective fan and or light unit. Possibly weak or damaged insulation somewhere between the hot or neutral and the ground. Because it is not arcing or smoking I would strongly suspect a neutral to ground fault. Wouldn't trip a regular breaker but GFIs are sensitive to this sort.
Somewhere in the fan/light you have a classic 'ground fault', not trying to be cute here. A GFI in effect measures the current going out on the hot and compares it to the current coming back on the neutral.
If the ground makes connection to the neutral ahead of the GFI some of the neutral current goes down the ground wire. Minus this current diverted to the ground wire the current remaining on the neutral no longer matches the current flowing down the hot wire leaving the GFI. You can often check this by disconnecting the ground on the circuit and seeing if the GFI still trips. I expect it won't .
Once you know this it should be a simple matter of laying everything open and disconnecting a piece at a time to isolate what is causing the problem. Time and trouble but not too difficult.