How to Check a Circuit Breaker

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  • 2 hours
  • Intermediate
  • 50
What You'll Need
Battery operated light
Screwdrivers
Multimeter
Circuit breaker

The basic function and purpose of circuit breakers found in today’s homes are to interrupt the flow of current as soon as a fault is detected within a circuit, relative to each of three types of breakers used—the standard, the GFCI, and the AFCI circuit breakers (CB).

The standard CB (Figure 1) is designed to detect an excess of current flowing through a circuit and exceeding the rated CB value or a sudden surge of current such as one caused by a short circuit.

The GFCI CB (Figure 2) designed to “sense” the slightest differential in current between the amps flowing-in through the hotline and the amps returning through the neutral line when the slightest amount is unintentionally diverted through an alternate path such as a human body, thus saving lives.

The AFCI CB (Figure 3) designed to “sense” any irregular “arcing” that neither of the other CB types is able to detect, caused by current leaks between hot and neutral lines within a circuit, usually caused by old, degraded, or damaged cables. Often occurring inside walls, it is known as the most common cause of electrical fires.

circuit breaker elements

Circuit breakers are designed to last for decades, but occasional or frequent tripping will cause them to deteriorate and eventually fail you. Regular systematic inspection of the electric panel can be beneficial and should be performed periodically. Pay particular attention to those breakers that trip often as the electrical sparking whenever they’re turned on or off will gradually corrode and burn the contacts. There are several issues that can alert you to malfunctioning circuit breakers.

Here's a step by step approach to inspecting your circuit breakers.

Issue 1 - Breaker Tripping Frequently or Not Staying Reset

While resetting it, the tripped breaker clicks as you switch it off but doesn’t stay in the on position. It could be caused by a short circuit, an overloaded circuit, or the current arcing across due to faulty wiring.

Step 1.1—Switch off the breaker.

Step 1.2—Go around unplugging and switching off everything affected by that circuit while observing for burnt or scorch outlets and plugs and burnt smells. That would give you a clue to the possible cause.

Step 1.3—Switch the breaker back on. If it still trips the problem is likely mechanical and the breaker must be replaced. If not, the issue is probably with one of the fixtures or outlets in the circuit.

Step 1.4—Switch and re-plug everything back on, ONE AT A TIME waiting a few minutes between each one, until the breaker trips again.

Step 1.5—With the probable culprit isolated, unplug and turn back off everything else on that circuit. If the breaker still trips, it will confirm that the outlet—or what’s plugged into it—is bad and needs to be fixed.

Step 1.6—If it does no longer trip with everything else off, however the cause can be a circuit overload from too many appliances—which will require adding a new outlet circuit. Alternately, it could be from arcing where current leaks in old or deteriorated wiring inside the walls.

If you’re not sure which, it’s probably time to seek professional advice.

Issue 2 - Switch Lever Moves Freely but Can’t Be Reset.

This is usually a mechanical failure from one of the breaker’s internal components (Figures 4 and 5) operating the lever, but just to confirm that it’s not electrical, turn off the main panel breaker and test it again. If the problem remains, replace the breaker

circuit breaker trip bar

If the problem disappears, continue troubleshooting by following the steps in “Issue # 1”.

Issue 3 - Breaker Is On but Doesn’t Power the Circuit

Step 3.1—This is where a decision must be made to either call in a professional to investigate further and repair the problem or if you have adequate previous experience of electrical work inside an electric panel, to push it a step further.

Step 3.2—At this stage, safety must be the very first concern as access is opened to the full 200 plus amperage of your house’s electrical entrance. Get a battery-operated light and switch off the main breaker to the panel (Figure 6 & 7).

circuit breaker panels

Step 3.3—Remove the front cover to the main panel exposing the wiring to each breaker terminal (Figure 7).

Step 3.4—Verify that the wires are properly secured to each terminal, then remove the breaker from the bus bar (Figure 8).

circuit breaker fixing

Step 3.5—Switch the breaker on and with a multimeter set to continuity, measure across the switch terminals, or each switch terminals as in Figure 8. A switch resulting in an infinity ) reading is a defective breaker and must be replaced.

Step 3.6—If the breaker turns out to be good, the problem is most likely a broken or disconnected line at one of the receptacles or fixture boxes along the circuit.

Step 3.7—Re-install the breaker, wires, and front main panel, since the breaker is good, and proceed to troubleshoot the rest of the circuit, or call for professional assistance if you don’t feel comfortable doing it yourself.

Issue 4 - Standard Breaker Tripping with the Slightest Load

This is a common internal problem often seen in defective circuit breakers where the breaker’s actual rating value changes due to components deterioration or failure. It will require the replacement of the breaker. If the problem still persists, however, investigate further by following the steps 1.1 through 1.5.

Issue 5 - Humming Sound Inside the Circuit Breaker Box

A buzzing, sparking or fizzling noise coming from a circuit breaker is usually caused by a bad or corroded internal contactor, or from the circuit drawing too much current.

Step 5.1—Open the electric panel’s door and take an inquisitive look inside at all the breakers, paying close attention for burning odors indicating that wires and insulation are overheating or that a breaker’s plastic casing is melting.

Step 5.2—When burning smells are detected, feel the breakers and around them with your hand for signs of the one that’s heating up to isolate it and switch it off.

Step 5.3—If no heat is detected and the smell persists, switch off the main breaker to the panel (Figure 6). For your safety, the removal of the front panel must be done with the main breaker of the panel turned off and remain turned off until the cover is back on.

Step 5.4—If you feel comfortable accessing the inside of the main panel, remove its front cover and listen for where the noise comes from, inspect the wires, terminal connections, and breakers for scorching or burnt parts and wires and pay attention to burnt smells and where they originate.

It is imperative to locate and replace the bad breaker, as the humming or buzzing indicates resistance and will eventually cause a fire.

Whenever a circuit breaker needs replacing, be aware that there are different types, different makes, and different ratings of circuit breakers. Where there was a GFCI CB, replacing it with a standard CB will “work” but it will not provide the proper protection to you and your family, and different brands are not interchangeable.