Buying Guide

Types of Circuit Breakers

Types of Circuit Breakers
A single-pole and a double-pole circuit breaker.

The three types of circuit breakers are standard, GFCI and AFCI. Each handles different amp capacities and operates in different locations in the home. 


Standard circuit breakers monitor the flow of electricity as it enters your home and makes its way through your electrical wiring system to outlets and appliances. 


In the event of an overload or short circuit — caused when a hot wire touches a neutral wire, ground wire or another hot wire — the breaker trips and breaks the current to prevent wires from overheating, diminishing the potential for electrical fires. Standard circuit breakers are either single- or double-pole.


Single-pole breakers 

  • Are the most common breakers used in homes.
  • Protect one energized wire. 
  • Supply 120V to a circuit. 
  • Handle 15 to 30 amps. 
  • Available in three types: Full size (1-inch wide), half size (1/2-inch wide) and twin/tandem (1-inch wide with two switches and controls two circuits).


Double-pole breakers

  • Occupy two slots on a breaker panel and protect two energized wires. 
  • Consist of two single-pole breakers with one handle and a shared trip mechanism. 
  • Supply 120V/240V or 240V to a circuit. 
  • Range in capacity from 15 to 200 amps. 
  • Are required for large appliances such as dryers and water heaters.


GFCI Circuit Breakers
A GFCI circuit breaker.

Ground fault circuit interrupter (GFCI) circuit breakers cut power to the circuit when they are tripped by an overload of current, a short circuit or a line-to-ground fault, which occurs when an unwanted path forms between an electrical current and a grounded element. 


All GFCI breakers have test buttons on the front and coiled wires. GFCI breakers are required in wet locations such as kitchens, bathrooms, outdoor areas, basements and garages. They are also recommended for workshops and areas where power tools are in use. 


Tip: GFCI protection is not recommended for appliances that must run all the time, such as refrigerators or medical devices, as the breaker may trip without your knowledge. 

AFCI Circuit Breakers
An AFCI circuit breaker.

Arc fault circuit interrupter (AFCI) circuit breakers protect against an unintentional electrical discharge in an electrical cord or wiring that could cause a fire. Once the breaker senses the electrical jump and abnormal path, it instantly disconnects the damaged circuit before the arc builds enough heat to catch fire. 


Arcs generally occur due to worn or damaged electrical cords and wiring. Regular circuit breakers don’t always trip in these instances because standard breakers are designed to respond to a sustained amount of heat, not a quick surge. 


Combination arc fault circuit interrupters (CAFCI) protect against the same arcs covered by AFCI as well as low-energy series arcing. They are becoming more common in homes as they protect downstream branch circuit wiring and power cords.


Dual function CAFCI/GFCI circuit breakers are a new type that protect against both arc faults and ground faults, which can save time and money while providing more safety than the other versions.


When installing, check the latest National Electrical Code, as requirements in most areas call for AFCI breakers in all rooms of the house under the 2017 code update. National building codes require AFCI breakers be used instead of standard breakers in new homes. 

Compatibility
A man installing a circuit breaker into an electrical panel.

The circuit load will determine the breaker size you need – and you’ll need to make sure to get the right brand, as all breakers are not interchangeable. 


Load Capacity: Determine the amp size of the circuit breaker you need to install based on the total circuit load. Remember that the safety rating for circuit breakers is 80 percent of the maximum load.
 

Tip: Most appliances have the amp rating listed on them. Permanently installed large appliances such as A/C units, washing machines and ovens require their own dedicated circuit. Consult an electrician if you are unsure of your total circuit load. 


Brand: Always install the correct brand of breakers in your breaker panel. While some breakers are interchangeable, many are not, even if they look the same. Replacing one brand of breaker with another can be dangerous, may void your breaker or panel warranty, and may cause you to fail an electrical inspection. Look on your breaker panel door for information about which breakers are compatible with your panel. Breakers continue to be manufactured for most panels, including older models.

Electrical Safety

Working with circuit breakers is dangerous and best left to licensed electricians due to the high voltage involved. Even minor jobs may require a permit, so check local building codes. 


  • Always shut off the main breaker in the breaker box before beginning any work in a breaker panel.  
  • Be sure the device you choose matches the wiring, load requirements and type of breaker panel you have. The information should be on the breaker panel door. 
  • Never replace a circuit breaker with one of a higher amp rating. 
  • Only add an additional breaker if you have an open slot in your breaker panel. 
  • The bus bar in the electrical panel may still be hot even if the main power is off. 
  • The wires leading into the electrical panel are always energized and should never be touched.  
  • Always have new electrical work inspected to ensure that it's properly installed and meets code requirements. 
  • Test AFCI and GFCI breakers every month to ensure they are in good working condition.

Circuit breakers provide overload protection to your electrical systems and ensure proper power distribution. Make sure you use the correct type of breaker to avoid an electrical overload or short circuits.


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