how to test a circuit breaker with multimeter



Have you ever experienced a situation where a circuit breaker in your home trips frequently, leaving you in the dark? A faulty circuit breaker can be a nuisance, disrupting the flow of electricity and causing inconvenience. Fortunately, you can use a multimeter, a versatile tool for measuring voltage, current, and resistance, to test the functionality of a circuit breaker. In this article, we will guide you through the process of testing a circuit breaker using a multimeter, enabling you to identify and resolve potential issues promptly.

Why Test a Circuit Breaker?

Before diving into the testing process, it is essential to understand why one should perform this task. Conducting regular tests on circuit breakers can help ensure that they are functioning correctly and are capable of protecting electrical systems from overload or short circuits. A malfunctioning circuit breaker may fail to trip when it should, potentially causing damage to appliances, wiring, or even electrical fires. By using a multimeter to test your circuit breaker, you can detect any faults and take appropriate actions to prevent these hazardous situations.

Preparing for the Test

To begin testing your circuit breaker, there are a few preparations to undertake. Firstly, ensure you have a multimeter suitable for measuring voltage and resistance. You will also need protective equipment like insulated gloves and safety glasses to minimize any potential risks. Familiarize yourself with the layout of your electrical panel and identify which circuit breaker you want to test.

Testing Voltage

The first step in testing a circuit breaker is to measure the voltage across it. This test determines whether the circuit breaker is receiving electricity and can effectively carry current. Follow these steps to perform the voltage test:

1. Turn off the circuit breaker: Start by switching off the circuit breaker you intend to test. This precautionary step ensures your safety during the process.

2. Set the multimeter to AC voltage: Choose the AC voltage setting on your multimeter, typically denoted by a "V" with a squiggly line.

3. Test the line side terminals: Locate the line side terminals on the circuit breaker. These terminals receive the incoming electrical supply. Place the multimeter probes on each of these terminals, making sure they do not touch any other part of the electrical panel.

4. Read the voltage: With the multimeter probes securely in place, switch on the circuit breaker. Observe the multimeter display, which should show the voltage being supplied to the circuit breaker.

5. Interpret the results: A properly functioning circuit breaker should display the expected voltage. If the multimeter reading indicates no voltage or a significantly low value, it may signify a problem with the circuit breaker.

Testing Resistance

In addition to voltage testing, measuring the resistance of a circuit breaker is crucial for detecting any internal faults. This test involves checking if the circuit breaker allows electricity to flow through it as it should or if it is obstructed. Follow these steps to perform a resistance test:

1. Make sure the circuit breaker is off: As a safety precaution, turn off the circuit breaker you wish to test.

2. Set the multimeter to resistance mode: Select the resistance mode on your multimeter. It is typically represented by an Ω (omega) symbol.

3. Identify the load side terminals: Locate the load side terminals on the circuit breaker. These terminals connect to the devices or appliances that the circuit breaker supplies power to.

4. Connect the multimeter probes: Place one multimeter probe on each of the load side terminals, ensuring no contact with other parts of the electrical panel.

5. Measure the resistance: With the probes securely attached to the load side terminals, turn on the circuit breaker and observe the multimeter display. It should show the resistance of the circuit breaker.

6. Analyze the results: A healthy circuit breaker will exhibit a low resistance value, indicating smooth electrical flow. If the resistance reading is unusually high or infinite, there may be an issue with the circuit breaker.

Testing Continuity

Continuity testing is essential to ascertain the integrity of a circuit breaker's internal connection. It involves checking if the circuit breaker's contacts are closing and conducting electricity as intended. Follow these steps to perform a continuity test:

1. Turn off the circuit breaker: As always, switch off the circuit breaker you are testing to ensure safety.

2. Switch the multimeter to continuity mode: Set your multimeter to the continuity mode or resistance mode if it has a built-in continuity feature. This mode usually provides an audible beep when continuity is present.

3. Place the multimeter probes: Position one probe on the line side terminal and the other on the load side terminal of the circuit breaker. Take care to avoid contact with any other electrical components.

4. Activate the continuity test: Turn on the circuit breaker and listen for the multimeter beep or observe the resistance reading on the display.

5. Interpret the results: If the multimeter emits a beep or displays a low resistance value, it signifies that the circuit breaker's contacts are working correctly. Absence of continuity or high resistance may indicate a faulty circuit breaker.

Testing Ground Fault Circuit Interrupter (GFCI) Breakers

Ground Fault Circuit Interrupter (GFCI) breakers are specifically designed to protect against electric shock by monitoring the flow of current between hot and neutral conductors. Testing a GFCI breaker ensures it can promptly identify ground faults and trip. Here's how to test a GFCI breaker:

1. Locate the GFCI breaker: GFCI breakers are generally installed in areas where water is present, such as bathrooms, kitchens, or outdoor outlets.

2. Press the "Test" button: Locate the "Test" button on the GFCI breaker and press it. This action should cause the breaker to trip and cut off power to the circuit.

3. Observe the breaker state: After pressing the "Test" button, the breaker should move to the tripped position. If it remains in the ON position, it indicates a faulty GFCI breaker that should be replaced.

4. Press the "Reset" button: To restore power, press the "Reset" button on the GFCI breaker. It should return to the ON position, allowing electricity to flow.


Testing a circuit breaker with a multimeter is a straightforward but vital procedure to ensure the safety and reliability of your electrical system. By following the steps outlined in this article, you can effectively measure voltage, resistance, and continuity to determine the functionality of your circuit breaker. Regular testing is paramount to identify any issues promptly and take appropriate measures to rectify them. Remember, safety is paramount, so always exercise caution while working with electricity and use protective equipment.


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