A GFCI uses a current transformer (CT) to detect differences in current between the ungrounded (hot), and the grounded (neutral) conductors. Since the GFCI is tripping with only the grounded (neutral) conductor connected, that means that there's current on the grounded (neutral) conductor. This would lead me to believe, that this neutral is tied to the neutral of another circuit somewhere.
You'll want to make sure this isn't part of a multi-wire branch circuit. If the neutral in question enters a cable with two hot conductors, it's likely a multi-wire branch circuit.
If not, you'll want to look for places where this circuit might be in close proximity to other circuits. A multi-gang box with two or more devices, would be a prime suspect. If you find such a location, you'll want to open it up and make sure the grounded (neutral) conductors are separated properly. It's common; especially with DIYers, to simply connect all the grounded (neutral) conductors in a box together. However, this can lead to the exact problem you're describing.
Residential Kitchen
In a dwelling unit (residential), GFCI protection is only required for kitchen receptacles that serve the countertop surfaces. There's no requirement to GFCI protect receptacles that serve a refrigerator. Unless the fridge is plugged into a countertop receptacle.
National Electrical Code 2014
Chapter 2 Wiring and Protection
Article 210 Branch Circuits
I. General Provisions
210.8 Ground-Fault Circuit-Interrupter Protection for Personnel. Ground-fault circuit-interrupter protection for personnel shall be provided as required in 210.8(A) through (C). The ground-fault circuit-interrupter shall be installed in a readily accessible location.
(A) Dwelling Units. All 125-volt, single-phase, 15- and
20-ampere receptacles installed in the locations specified in
210.8(A)(1) through (10) shall have ground-fault circuit interrupter protection for personnel.
(6) Kitchens— where the receptacles are installed to serve the countertop surfaces.
Garages, Unfinished Basement, and Other Locations
If the refrigerator is in a garage, boathouse, or unfinished basement. All the receptacles are required to be GFCI protected, so the fridge will have to be plugged into a GFCI protected receptacle.
Why does the fridge trip the GFCI?
Any inductive load when switched off, can produce electromagnetic interference (EMI). This interference can, and often does, trip GFCI devices. Most vapor compression refrigerators have a few inductive loads, any of which could cause the trip.
Is there anything that can be done?
There are devices called snubbers that can be used to reduce, or eliminate the effects of EMI. Installing one between the fridge and the GFCI device, could prevent nuisance trips. The best solution though, is to connect the fridge to a non-GFCI protected circuit.
If that's all it takes, why isn't there already one built in?
While most (all) manufacturers are aware that refrigerators can cause nuisance tripping of GFCI devices, most (none) seem willing to provide a solution. It would be complete speculation for me to try and tell you why they don't care, so of course I'll go through a few possibilities.
- Cost.
Plain and simple, it costs money to implement a solution.
- Warranties and Operating Conditions.
Most refrigerators are designed to operate in a kitchen. Running them in dusty, dirty garages and basements could lead to more warranty covered repairs.
An electrician put an electrical outlet box in our covered porch ceiling. We want to hang a light fixture (one with a cord and plug over a dining table). I will be installing the outlet myself. Do I need a GFCI outlet or just a 15 amp regular outlet? The wiring is in the attic above the ceiling. The porch has sliding glass windows, the ceiling cannot get wet from rain, but there is normal humidity when the windows are open.
Best Answer
It sounds like you described a damp area, like a bathroom. Bathroom lighting does not require GFCI. But...
First, you are never required to use a GFCI receptacle. You can use a plain receptacle, and if GFCI protection is even required, that can be provided from another GFCI device upstream. Also, having a GFCI device past a light switch is a bad idea, so if this is sourced from a wall switch, no GFCI here. That's a hardware limitation, not Code.
You also can't put a GFCI where shorter members of your family need a ladder to reset it. How will they see to work?
Also practical, you don't want to put any GFCI device where it'l be exposed to rain, spray or condensate, so an upstream/more indoor location is more appropriate. You wouldn't charge your iPhone out here!
The next question to ponder is whether you'll be touching or contacting this light. Bathroom lights are generally grounded and garage or hi-bay lighting is usually unreachable. If frequent contact or no ground, there’s a practical argument to be made toward GFCI protection, just because it "takes off the table" any risk of electrocution.
Now ceiling receptacles are perfectly normal for lighting. Wiring luminaires via cord and plug connection is perfectly allowed due to NEC 400.6.