How To Find A Ground Fault With A Multimeter?

Most of our houses are built with an electrical grounding system; these systems help to prevent electrical faults and shocks. They are called the Ground Fault Circuit Interrupter (GFCI), but the groundings themselves can develop some kinds of flaws after some years.

Ground faults likely to occur in wet or damp areas of your house, like your kitchen or bathrooms, where electrical insulators might have been degraded. Ground faults are caused when your damaged wires or faulty appliances create contact between electrical conductors and the ground. So when your GFCI trips consistently, you have to see it as a warning you shouldn’t ignore so that you can maintain the safety of your home.

Now to detect the ground fault, you would need to make use of a multimeter, so the question comes down to, “How do you find ground faults with a multimeter?” It is always better to prevent, so we would guide you on how you can troubleshoot this faults with the multimeter before it damages the safety and efficiency of your home.

Before we start, check this video:

How To Find A Ground Fault With A Multimeter?

1. Check the GFCI

  1. The first thing to do is to check your ground fault circuit interrupter to ensure that there are no faults from it. To do that, you should check for the reset and trip buttons. Then push the reset button, because in some cases the failures could be with the switch, so check to see if it clicks and stays in place.
  2. You should also test it with a multimeter (for example, Fluke 115) to confirm that it is receiving a voltage, by turning off your power supply, disconnecting all your connected appliance, then turning the power back on.
  3. Set the AC voltage to the highest scale on the multimeter, for a single pole breaker your multimeter should read 110 volts after you place the probes in order of the black lead to the silver screw and the red lead to the brass screw.
  4. For two pole breaker, place the probes to the screws in the same order as above, but for this, the multimeter should read 220 volts. If it doesn’t, then your GFCI might need a replacement.
  5. Even if the GFCI detects the voltage and the button wouldn’t pop out after you have clicked it, then you should consider replacing the outlet.

!!! Before attempting any electrical test, for your safety, you should be sure you feel confident to do so if you have any doubt hire a professional to carry out these tests !!!

2. Check the Wiring

After you have attempted all this, we now get to the part, where you may have to dismantle the outlet, but before you do so, it is mandatory that you turn off all the power supply of your house.

  1. The next thing you do is to unscrew the GFCI outlet and detach it from the wall, then check the wiring to see that they are connected correctly. Then you can power back the electricity of your house and note that by this action, you have put live energy in the circuits, so carefully check the voltage of the GFCI by using a multimeter.
  2. Grounding fault is caused when the neutral wires that are connected to the earth come in contact with a conducting wire. With a digital multimeter, you can detect the unwanted voltage that is between two points. You can initiate the test by setting your multimeter to measure DC voltage, then connect the multimeter probes to the wires by place one lead on the positive and the other point on the negative; then your multimeter should read an open circuit voltage.

After that connect the multimeter negative to ground, it should read zero volts, also connect the positive to the ground; it should also read zero volts. If you have any reading asides this, then you have a ground fault.

If you need to replace a GFCI outlet, here’s how to do that:

3. Check the other Outlets

If your readings from the wiring check are accurate, you might need to perform some other checks. Your GFCI might not be receiving any voltage from outlets, so you should test your outlets with the multimeter. It could be that the outlets are not feeding the GFCI properly.

For situations where there are more than one GFCI connected to the same circuit, you would also need to reset all the GFCIs, to ensure that the power loss from the outlets is not the fault of a trip.

4. Check the Circuit Breakers

If the fault is not with the outlet, it may be that the GFCI is not receiving power from the breakers. To know the circuit that needs attention, confirm that they are not flipped.

In cases of a ground fault, they could have been tripped or accidentally switched off, so check your electrical panel to see that they are intact, if they are not, you can flip the switch.

Now, in some cases, when you flip the breakers, they won’t stay, and this is no longer a problem we suggest you should handle yourself, you should hire a professional to attend to it.

Conclusion

It might start with a slight tingling shock, here and there until you your electricity begin to develop some faults. When grounding faults occur, the GFCI circuit breakers trip, and may require some attention, the GFCI breakers might trip for several reasons, but grounding fault is one of them.

  • We would also like to warn that when performing any of the tests, ensure that you take proper safety precautions, by wearing insulating gloves.
  • Also, we advise that with situations of high currents or high voltages, hire a professional who has proper knowledge of the equipment and protective gears to be used. When working with a standard digital multimeter, make sure that the voltage you are testing is not higher than 120/240 volts AC power 40 volt-ampere.

You should note that ground faults trip GFCI circuit breakers, so checking your GFCI is a good way to start the test, then next check the wiring, and the other outlets, then lastly check the circuit breakers.

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