GFIC Nuisance Tripping

What is a Ground Fault Circuit Interrupter?

GFCI for short, some refer to as GFI. It's that special plug you find in your bathroom, kitchen, garage and anywhere else that is considered a wet location. Contrary to what some may think, they do not protect your electrical equipment, fuses and circuit breakers do. GFCIs are there to protect personnel. The circuitry inside compares the current coming from the ungrounded conductor to the grounding conductor. If the current is off by a few milliamps, it trips. This is normal if there is a ground fault so that you don't get shocked, or electrocuted. Think of it as a safety measure against a toaster in the bathtub, if you're ever trapped in an 80s horror movie.

GFCIs can also be built into equipment itself. Hair dryers have them in the plug as do window unit air conditioners. Additionally, they may be found inside of an electrical panel. Newer properties may have a GFCI built directly into the circuit breaker. This style usually stands out compared to normal ones, as they will have a small button marked 'test.' 

Whatever style you see, they tend to have some text telling you to test them monthly. To test, you simply hit the test button, use a specialized GFCI tester, or use a non-battery powered voltmeter. Testing with the voltmeter is done by testing the ungrounded(hot) conductor to the ground(grounding) conductor. Since these meters that a little bit of power to take a test measurement, they should make the GFCI trip almost immediately. Testing monthly should be worked into any PM schedule, it could save someone's life. 

What is a nuisance trip?

A nuisance trip is an unexpected trip without seemingly no action on your part. 

Radio equipment and walkie talkies are notorious for setting them off. You'll often hear a loud buzzing noise coming from the GFCI when trying to communicate over the airwaves when in close proximity to these devices. 

Moisture in the electrical could also be a culprit. Water can carry electricity and you wouldn't know if it's hidden inside the box your receptacle is housed in without removing the cover and checking the box. 

Equipment plugged into the circuit could be damaged. Just because it doesn't trip the breaker and run, doesn't mean it's safely operational.

There could also be a problem with wiring or devices downstream. Many GFCI protected circuits, only install a single one on the entire circuit and feed the rest of the line. Your kitchen and bathrooms may be wired like this. The outlet next to the sink trips, but it takes out everything on the counter. Likewise, an outlet on the counter could cause the one next to the sink to trip.

What to do?

1. First and foremost, isolate the circuit. What receptacles have been affected by the trip. Take a meter or testing device and see what lost power. 
2. Unplug everything from that circuit. 
3. Reset the GFCI, if it doesn't trip, skip to step 9.
4. If it does trip immediately, turn the power off at the breaker and take the GFCI from it's box to inspect for damage. If obviously damaged, replace it with a new one, turn the power back on and see what happens after resetting the GFCI. If it's still immediately tripping or was undamaged, turn off the power, disconnect and cap off the wires from the load side. Turn the power back on. If this fixes the trip, the issue is down the line.
5. Turn the power off again, reconnect the wires to the load side. 
6. Now it's time to start disconnecting outlets from the circuit one by one. After one is disconnected, cap any wires that you disconnected, then turn the power back on.
7. If the outlet you took out doesn't solve the trip, repeat step 6 till you isolate your problem receptacle. Replace the receptacle with a new one. 
8. If there is still a problem after replacing, you have a wiring issue. Disconnect the causes of the trip so the rest of the circuit can work properly, while you plan out or schedule a wiring job. Since that job is beyond the scope of this, it will be covered in another post.
9. Start plugging in what was on the circuit one by one. Turning on the device and waiting a few minutes before moving onto the next. The reason to wait a few minutes, is the device causing the issue may be time delayed problem, such as a fan or heating element turning on after starting up. One of these devices will be your problem. Set aside the problem device or devices and fix or replace them as you see fit.
10. Congratulations on fixing the problem or isolating it down to the wiring.

As always, when working with electricity, be safe. Test anything you plan on touching. Never assume the power is off without first testing it. Practice lock out tag out.