How to Install a New Circuit Breaker

Electrician doing electrical work in breaker box
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Swapping out an old or faulty breaker is a simple way to address electrical problems around your home. Here’s a quick guide to help you identify a faulty breaker and install a replacement.

What Are Circuit Breakers?

Circuit breakers are devices designed to regulate the flow of electricity throughout your home. Breakers cut the flow of electricity in the event of an overloaded current and eliminate the risk of fires, burned wiring and ruined appliances.

Circuit breakers are housed in a breaker box. Most breaker boxes are found in basements, utility rooms and laundry rooms. Call a pro to help you find your breaker box if you’re unsure where it’s located.

Types of Circuit Breakers

Circuit breakers come in standard, ground fault interrupter (GFCI) and arc fault interrupter (AFCI) models. Here’s a look at each type of breaker:

  • Standard Circuit Breakers: Standard breakers monitor the flow of electricity to your home’s outlets and appliances and cut power in the event of an overload or short circuit. Most standard breakers protect one energized wire and supply 120 volts to a circuit. Standard circuit breakers also come in double-pole models, which protect two energized wires and can handle up to 240 volts.
  • Ground Fault Circuit Interrupter (GFCI): GFCI breakers cut power in the event of an overload, short circuit or line-to-ground fault. Line-to-ground faults happen when electricity forms an unwanted path between a current and a grounded object. GFCI breakers are required in wet areas of your home like bathrooms, kitchens, basements and garages. It’s also a good idea to install GFCI breakers in places like shops and outdoor areas.
  • Arc Fault Circuit Interrupters (AFCI): AFCI breakers detect a wide range of unwanted electrical arcs and help prevent fires. Arcs can occur due to faulty or worn wiring. Conventional breakers are designed to detect constant heat or current rather than quick surges or arcs. An AFCI breaker will disconnect in the event of an immediate surge.

    Breakers also come in single- and double-pole varieties. Single-pole breakers are common in most homes and supply 120 volts to a circuit. Double-pole models occupy two slots in a breaker panel and supply 120 or 240 volts to a circuit. Larger appliances like dryers and water heaters require double-pole breakers.

    Tripped Breakers

    In most cases, tripped breakers don’t require a replacement. You can fix a flipped breaker by simply pushing the switch back to the on position. Be sure to turn off light switches and unplug major appliances in the affected room before flipping your breaker. Continuing to overload the circuit will result in constant power outages.

    Identifying Faulty Breakers

    Constant electrical interruptions, appliance-specific overloads, switches stuck in the off position and burned breakers are common signs of questionable breakers. Be sure to replace any problematic breakers immediately. Ignoring a broken breaker will threaten the safety and efficiency of your home. Burned and hot-to-the-touch breakers are especially dangerous. Call a pro if you notice heat-affected breakers. This can sometimes be a sign of more serious electrical malfunctions.

    You can also use a multimeter to test the condition of your breakers.

    Begin by unplugging and switching off all the appliances connected to your problematic breaker. Next, remove the breaker box cover and make sure the breaker is in the on position. Touch your multimeter’s red power lead to the screw connected to the breaker by a black wire. Place your black power lead on the grounded breaker box. If your multimeter doesn’t have a reading, your breaker is faulty and needs to be replaced. If there is a reading, it should match the voltage of your breaker (120 or 240). A lower voltage is usually a sign of faulty wiring. Hire a professional electrician to diagnose the problem.

    Installing a New Breaker

    Once you’ve identified the faulty breaker, it’s time to install a replacement. Here’s a step-by-step guide:

    1. Power down. Shut off your branch circuit breakers one at a time. Next, turn off the power to your breaker box by flipping the power main. Your power main should be a large switch above or below your breaker panel. Call a professional if you’re unsure how to locate your power main.
    1. Remove the panel cover. Unscrew the panel cover to gain access to the breakers.
    2. Loosen the terminal screws. Turn the screws until the terminal and wires are loose. Pull the wires out of the breaker terminals.
    3. Remove the breaker. Press the breaker handle toward the outside of the breaker panel until it comes loose.
    4. Install your new breaker. Line up your new breaker with the clips on the side of the bus bar. Press the breaker down firmly until it snaps in place. Reconnect the wires to the terminal screws and replace your panel cover.
    5. Power up. Turn on the branch circuit breakers and your power main.

    When to Call a Professional

    Installing a new breaker is a simple DIY job. But certain circumstances can present a real danger to you and your home. Always call a professional if you’re unsure about replacing your breaker or notice dangerous signs like moisture, burns or corrosion around your breaker box.