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The storm is coming, and this time you’re prepared. You've got your stockpile of food and water, a portable generator and a supply of fuel to get you through a week with no power. You start up your generator, plug in your refrigerator and … the generator trips.
You turn off your generator and reset the “breaker”, restart and five minutes later the power is out again.
This is an especially frustrating scenario for homeowners who are depending on a portable generator as back-up power in an emergency.
There are a couple common causes for portable generator tripping, and the solution could be ensuring the power cord is sized correctly for the amperage of the device.
In general, there are two devices that can “trip” (shut off power) on a portable generator – the Ground Fault Circuit Interrupter (GFCI) receptacles and the circuit breaker. Both are protection devices, but they serve different purposes and detect different problems.
Circuit breakers (and fuses) are overcurrent protective devices that will trip if you’re drawing more amps than the circuit can provide.
The GFCI receptacle senses electrical “leaks” – electrical current is escaping the device and taking a different path to ground other than the one provided for the device. Leaks are usually caused by water, dust, worn insulation, a defective electrical appliance or the human skin. A GFCI will trip and shut off power when a leak is detected to protect against electric shock, electrocution, burns, and fires.
First, confirm that your generator has GFCI receptacles. Most Cat® portable generators are built with GFCI as a standard safety feature, but some manufacturers only include GFCI on “professional” models.
Next, check to see if the circuit breaker is tripping before and / or simultaneously with the GFCI receptacle trip. If the circuit breaker trips, confirm that you’re not overloading the generator. If the breaker doesn't trip but the GFCI does trip, you may have an electrical leak. Follow the troubleshooting steps below:
Step 1. Turn off the generator. Disconnect all cords and devices from the generator. Then restart the generator.
Step 2. Reset GFCI receptacle by pressing the “Reset” button on the outlet. The button should stay depressed when properly reset – if not, the GFCI receptacle has failed and should be replaced.
Step 3. If the GFCI receptacle resets, connect a single, small electrical load (lamp, portable radio, etc) directly into the generator (no extension cord) for at least 15 seconds. Does it trip? If not, then the GFCI receptacle is probably operating properly. Go to Step 4. If it does trip, then repeat this step with a different lamp, radio, etc. to make sure the problem isn't with your lamp, etc. If the GFCI receptacle still trips, then the GFCI receptacle requires further testing by qualified service personnel. Stop troubleshooting and have your generator properly serviced. Otherwise, unplug the single electrical load and proceed with troubleshooting.
Step 4. Connect your extension cord and repeat step 3 (plug in your lamp, radio, what have you, for at least 15 seconds). If you’re using multiple extension cords, test one at a time, and make sure all intermediate connections are tight and not exposed to dirt or moisture. If, at any time, the GFCI receptacle trips, then a defective extension cord has been detected. Replace the extension cord with a new, dry extension cord and try again.
Step 5. If you were using a multi-outlet power strip, try connecting it now and plug in an electrical load. If not, then proceed to step 6. If the GFCI receptacle trips, then a defective multi-outlet strip has been detected. Replace the multi-outlet strip with a new multi-outlet strip and proceed with troubleshooting.
Step 6. Once you've verified that your extension cords and power strips aren't leaking, connect other electrical loads one at a time to see if they trip the generator.
If the GFCI receptacle trips, then a defective (“leaky”) electrical load has been detected. The generator should be turned off and the electrical load should be unplugged and replaced or serviced by qualified personnel.
Still no trip?
It’s possible that the issue was eliminated during the recent GFCI receptacle trip, especially if the defect was caused by accumulated dirt, dust, and/or moisture.
Using multiple connections and extension cords greatly increases the chances of tripping the GFCI.
Multi-outlet strips should not be "daisy chained or jumpered", i.e. connected to one another. It’s not safe.
Make sure all your cord connections are dry (not in the rain or standing water) – this is not safe and likely to cause electrical leakage (and GFCI trips).
Older household appliances (freezers, refrigerators, etc) may be prone to electrical leakage and can cause the GFCI to trip. If this happens, contact appliance manufacturer to get more information.
Never operate a portable generator indoors, in a garage (even if the door is open) or near an air intake on your home – carbon monoxide poisoning is lethal.
Never operate a portable generator in the rain. This will damage your generator and cause a potential electrical hazard.