Testing transistor with multimeter in circuit breaker

Testing transistor with multimeter in circuit breaker

It is recommended that you learn how to test circuit breakers with a digital multimeter. If you know how, you can save time and money by troubleshooting basic problems without calling an electrician.

Tools needed

You will need the following tools to test circuit breakers.

A digital multimeter

A one-piece screwdriver to expose the breaker housing.

You can use any type or brand of digital multimeter to measure any current. It is important to know the correct settings for your application to avoid damaging the multimeter. Watch the "Ratchet" instructional video to learn how to test AC voltages with a digital multimeter.

Testing Circuit Breakers with a Digital Multimeter

How do I test a circuit breaker with an ohmmeter?

You can test circuit breakers with a digital multimeter in two ways.

Voltage testing

You can check the circuit breaker voltage directly on the control panel. Be careful when doing this, as you are working with live equipment. If the voltage is zero or below the standard value, your circuit breaker may be faulty.

Checking the resistance

You can also find a faulty circuit breaker by checking the resistance of the circuit breaker with a digital multimeter. This method is especially recommended when replacing a circuit breaker before installing it in a panel. It is also a safer way to test circuit breakers, as it is not necessary to test them with electricity.

Step-by-step instructions for testing circuit breaker voltages

Step 1: Open the circuit breaker

Use a flat-blade screwdriver to unscrew the circuit breaker cover. Hold it firmly before removing the last screw to avoid accidents. It is a good idea to ask someone to help uncover the breaker panel so that it does not come off.

Step 2: Set the multimeter to AC voltage.

Testing the Circuit Breaker with a Digital Multimeter

Set the multimeter scale to AC voltage and connect the black test lead to the common terminal and the red test lead to the voltage terminal. Note that some digital multimeters require a voltage setting. In this case, set the multimeter to a higher voltage than you have (typically 120V).

Once the unit is set up correctly, you can move on to the next step.

Step 3: Test the circuit breaker

Essential for continuity

To test the continuity of your circuit breaker, you must connect the black or common wire to the ground of the circuit breaker panel. Then connect the red wire to the energized line of the circuit breaker you wish to test. The single-pole circuit breaker should read about 120 volts.

If the reading is too low or there is no voltage, the circuit breaker is defective and should be replaced.

To test a 220 volt double-pole circuit breaker, connect the red and black wires of the digital multimeter directly to the terminals of the circuit breaker. The reading should be about 240 volts and you should test your two-pole breakers one at a time.

To test one side of the two-pole circuit breaker, place the common wire on the panel ground and the hot wire directly to one terminal of the circuit breaker. Both should be near 125 volts.

If the other side of your double-pole breaker is zero, you have a faulty breaker and it should be replaced.

Checking the resistance of a circuit breaker

To test the resistance of a circuit breaker, set the multimeter to ohms or resistance.

Then place one lead on the power terminal and the other on the screw terminal. You should be able to read the resistance value when the circuit breaker is open, and there should be no resistance value when it is closed.

Test the two-pole circuit breaker in the same manner. If it has no resistance when open, or no resistance when closed, your circuit breaker is defective and should be replaced.

Before you buy a new circuit breaker, take a look at these 10 best circuit breakers I've used in my projects. In this article, I explain the pros and cons of each type of circuit breaker so you can understand which one is best for you.

Summary

Did you find this guide to testing circuit breakers with a digital multimeter helpful? Knowing how to test a circuit breaker can save you money, as you can find out what's wrong before you call an electrician.

And if you need to buy a new circuit breaker, I recommend these ten most reliable circuit breakers I've used in past projects.

Did you find anything interesting in this article? Share it in the comments below.

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