GFCIs are very useful in kitchens, bathrooms and other areas where there’s a concern about potential shorts in an outlet. Depending on a client’s needs, they may require either specific receptacles with GFCI protection or you might protect entire circuits with GFCI breakers in the service panel. If anything goes wrong in a protected outlet or circuit, the unit trips and is shut off until the reset button is pushed. Most of the time, this is exactly the sort of protection that your client wants (and that local codes often require for wet environments).
If a GFCI unit keeps tripping, though, the reality is less than ideal. A good portion of these units are installed in damp or humid areas where water could cause shorts, and if you get called in because a GFCI keeps tripping then that’s probably the first thing you’ll check. If it’s not water that’s the culprit, though, here are a few other options you might consider.
GFCIs don’t do well in long circuits, especially if you’re only using the standalone receptacle versions. To prevent issues with repeated tripping you should avoid installing a GFCI receptacle in any circuit longer than 100 ft. Sometimes mistakes are made, and if you weren’t the original installer then you might not even be aware that the circuit is longer than it should be. This can be annoying as it may require some rewiring, but if you don’t reduce the length of the circuit then even replacement GFCIs may continue to yield nuisance trips.
Having one or even a few splices in a circuit is usually fine for GFCIs. The more splices there are, though, the more it strains the GFCI unit and the more likely it is to break the circuit. If the circuit has multiple splices in it, then replacing the wiring with a single length of wire may prevent the GFCI from tripping in the future.
Heavy Circuit Loads
Take a moment and look at what else is installed on the circuit with the GFCI. If there are heavy-load items such as fluorescent lighting, fans or other items with electric motors then they might be the cause of the problem. These items require a lot of electricity to operate, especially when starting up; the draw they create through the circuit may overwhelm the GFCI and cause it to trip. It may function perfectly fine most of the time, but once those heavy-load devices start up then you’re all but guaranteed a trip every time.
This isn’t talking about the GFCI itself, or even the circuit it’s connected to… this is referring to the equipment that’s plugged into the GFCI. Loose wires or other faults within the equipment can cause grounding issues that will trip the GFCI. It may not be evident if the equipment gets unplugged often or if the client unplugs it before attempting a reset. And depending on the issue with the equipment, it may not trip the GFCI consistently. This can be tricky to diagnose, so it’s important to always make sure that you find out what the outlet or circuit is being used for.
This is much more common with power cords that have a GFCI component built into them, though it’s possible that you might find some other GFCI equipment with this feature built in. Though it may seem annoying to have the GFCI trip frequently, these cords may trip by design every time the cord is unplugged or the power is otherwise deenergized. This ensures that connected equipment such as saws that you might see at a work site can’t automatically turn back on after a power outage. If the unit trips every time the power is turned off, that’s probably what’s going on.
What was the most annoying situation you’ve faced that involved a tripping GFCI?