How to Test a GFCI Socket with a Multimeter (5 Step Guide)

Do you think your GFCI outlet has gone bad? To find out what is causing the outlet to malfunction, it is best to test with a multimeter.

Follow these steps to test the GFCI outlet with a multimeter. 

First, you need to check your GFCI for any faults. To do this, use the "TEST" and "RESET" buttons. Next, insert the multimeter into the grooves. You need to make sure that there is power left in the outlet (while it is turned off). Next, measure the voltage at the outlet. This step is aimed at determining if the GFCI outlet is transmitting the correct voltage. Then check the wiring of the outlet. Start by turning off the power using the main switch. Unscrew the socket and remove it from the wall. Look for any patched wires or improper connections. Finally, check if the outlet is properly grounded. 

In this 5 step guide, we will teach you how to test your GFCI, which helps prevent electrical faults and shocks, using a multimeter for any ground faults.

Requirements 

1. Multimeter - A multimeter is a fantastic tool for measuring electrical parameters such as voltage, resistance, and current. You can choose between analog and digital multimeter. If you're on a budget, an analog multimeter will do. However, if you're looking for a more advanced device, a digital multimeter might be your best bet. In addition to higher resistance, they also offer accurate digital displays. DMMs are more suitable for measuring electrical voltage, especially when testing a GFCI outlet. (1)

2. Personal protective equipment – For hands, use insulating gloves capable of completely and reliably isolating electricity. It would be helpful if you also had an insulating mat that prevents electricity from passing from the floor and through your body in the event of a ground fault. Before and after troubleshooting the GFCI circuit breaker, you will need to determine the current flowing in the power supply. Carry a voltage detector with you instead of erroneously operating a live GFCI breaker. It will show the current electricity level. (2)

5-Step Ground Fault Testing Guide

Checking the GFCI output is a simple process if you are using a multimeter. Here are the detailed steps to find out if the GFCI switch is faulty.

1. Check GFCI (Ground Fault Circuit Breaker) 

You need to check the GFCI for faults. To do this, use the "TEST" and "RESET" buttons. Manually press the "TEST" button until you hear the socket click, which means that the power is off. Then press the "RESET" button. Sometimes the problem may be in the switch. See if it clicks and stays in place.

2. Inserting the multimeter into the slots 

You need to make sure that there is power left in the outlet (while it is turned off). Place the probes of the multimeter plug into the vertical slots, starting with the black wire and then the red wire. A reading of zero indicates the outlet is reasonably secure and confirms that it is still working.

To turn on the power, press the RESET button and continue to measure the voltage at the GFCI receptacle.

3. Measuring the voltage in the socket 

This step is aimed at determining if the GFCI outlet is transmitting the correct voltage. Set the analog or digital multimeter to the resistance value and select the maximum scale. Multimeters with a resistance setting greater than one position should be set to 1x.

You are ready for the ground fault test after setting up the multimeter. Connect one probe to the terminal so that the other touches the device case or mounting bracket. Then move the first probe touching the terminal to the other terminal. A ground fault is present if your multimeter reads anything other than infinity at any point in the test. Lack of reading indicates problems. You may want to consider checking the wiring of the outlet.

4. Checking the wiring of the outlet 

Start by turning off the power using the main switch. Unscrew the socket and remove it from the wall. Look for any patched wires or improper connections. Your wiring is not a problem as long as the black wire is connected to the "line" pair and the white wire to the "load" pair of wires. See if the colors match accordingly - black should go with black and white with white.

Check if the wire nuts are securely fastened to the connectors, if everything is in order. Return to the main electrical panel, turn on the power and check the voltage again with a multimeter. Be careful while doing this, because you have restored the living energy in the circuits.

5. Is the socket properly grounded?

This step is the same as step 3 (voltage measurement). The only difference is that the multimeter's black lead goes into the U-shaped (ground) slot of the ground fault interpreter. Expect voltage readings similar to those you selected earlier if the outlet is properly grounded. On the other hand, if you're getting a different voltage reading, you're dealing with an improperly grounded outlet or incorrect wiring.

Troubleshooting the GFCI switch should be a monthly affair. This is one of the things you must undertake for your own safety. If the socket stops working as before, replace it. You never know when he's going to bow.

How to fix a ground fault

The most appropriate way to eliminate a ground fault is to replace the faulty wire. If you are dealing with one or more bad or old wires, you can remove them and put in new ones. Sometimes a ground fault can be in a certain part. In such a situation, it is best to replace this entire part. Fixing this is unsafe and not worth the hassle. It is dangerous to use a part with a ground fault. To solve the grounding problem, buy a new part and replace it entirely. This is safer than fixing the part. Also, a new part gives you peace of mind because your GFCI circuit will be in perfect condition after you replace the ground fault part.

Eliminating a ground fault is not difficult. Perhaps the problem lies in finding them, especially when working with a large circuit or GFCI system. If so, break the scheme into smaller, more manageable sections. Also, here you will get a test of your patience. To avoid disappointment and ensure successful testing of the GFCI socket, take your time to finish. Do not rush.

Summing up

Did you find this article informative? Now that you've learned how to test a GFCI outlet with a multimeter, give it a try. As mentioned earlier, this procedure is worth doing every month as ground faults are potentially dangerous. In addition to dangerous electrical shock, ground faults can also cause the device to malfunction.

Take a look at some of our articles below.

• How to read an analog multimeter
• How to Use a Cen-Tech Digital Multimeter to Check Voltage
• Setting up a multimeter for a car battery

Recommendations

(1) limited budget - https://www.thebalance.com/budgeting-101-1289589

(2) current thread - http://www.csun.edu/~psk17793/S9CP/

S9%20Flow_of_electricity_1.htm