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Standard Circuit Breakers
The three main types of circuit breakers are standard, GFCI and AFCI. Some models have dual functionality. Each handles different amp capacities and operates in different locations in the home.
Standard circuit breakers monitor amp capacity of the devices they operate. Make sure to check the wattage and amperage of any device connected to a standard circuit breaker to make sure it can manage the load.
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 will interrupt the current to prevent wires from overheating, diminishing the risk of electrical fires. Standard circuit breakers are either single- or double-pole.
- 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).
- 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
Ground fault circuit interrupter (GFCI) circuit breakers cut power to the entire circuit. They are tripped by an overload of current, a short circuit or a line-to-ground fault. This can occur when an unwanted path forms between an electrical current and a grounded element.
GFCI circuit breakers can be a good choice when a circuit and everything connected to it require ground-fault protection. They are required in all 125-volt, single-phase, 15- and 20-ampere receptacles in locations such as finished basements, hallways and closets, kitchens, laundry areas and bedrooms.
It is not necessary to have GFCI receptacles on a circuit that is protected by a GFCI circuit breaker.
AFCI Circuit Breakers
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.
When having a circuit breaker installed, check the latest National Electrical Code, section 210.12 (A) 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.
CAFCI Circuit Breakers
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 breaker types protect against both arc faults and ground faults, which can save time and money while providing more safety than the other versions. CAFCI circuit breakers are required in all 15- and 20-amp circuits with the exception of locations where GFCI circuit breakers are required, including laundry rooms, kitchens, bathrooms, garages and unfinished basements.
Circuit Breaker Compatibility
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. Most appliances have the amp rating listed on them. Permanently installed large appliances such as AC 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 lead to a failed electrical inspection. Look on the 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 Tips
- Always shut off the main breaker in the breaker box before beginning any work in an electrical 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 energized even if the main power is off. It's always a good idea to work like everything is energized but if the bussing is energized after the main breaker is off please contact your local utility company because this should never happen.
- The feeder wires leading into the electrical panel are always energized and should never be touched.
- Always have new electrical work inspected by a licensed electrician or city/county inspector 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.
Installation or replacement of circuit breakers is best left to licensed electricians due to the high voltage involved. They understand electrical code requirements and the dangers of electric shock. Even minor jobs may require a permit, so check local building codes. Download The Home Depot Mobile App and check out the circuit breakers when it is time for your next project.
The three main types of circuit breakers are standard, GFCI and AFCI. Some models have dual functionality. Each handles different amp capacities and operates in different locations in the home. Standard circuit breakers monitor amp capacity of the devices they operate.What are the 4 classes of circuit breakers? ›
There are many different types of interrupting mechanisms in circuit breakers. Basically, the interrupting mechanism stops the current flow and shuts off the power. The most common types are air, oil, vacuum, MCCB, and ICCB.What are the two basic types of circuit breakers? ›
Standard circuit breakers come in two varieties: single-pole breakers and double-pole breakers. These are simpler breakers that monitor the cadence of electricity as it circulates an indoor space. It keeps track of electricity in electrical wiring systems, appliances and outlets.What is Type A and Type B breaker? ›
Firstly, Type A trips off the circuit when the current exceeds 2-3 times the actual current rating. Since this type is highly sensitive to short circuit, it is better suited for semiconductor devices. Next, type B, which trips off when the current flow is 3-5 times the actual flow and finds a use for cable protection.What are the different types of AC circuit breakers? ›
The AC circuit breaker is sub-classified into two types, i.e., the low voltage circuit breaker and the high voltage circuit breaker. The circuit breaker whose value lies below the 1000V is known as the low voltage circuit breaker, and above 1000V it is known as a high voltage circuit breaker.What are the 3 type classifications of circuit breakers? ›
There are three basic circuit breaker varieties: standard breakers (which include both single-pole and double-pole circuit breakers), ground fault circuit interrupter circuit breakers (GFCIs) and arc fault circuit interrupter circuit breakers (AFCIs).What is the difference between Type D and Type C breakers? ›
Type C devices are the normal choice for commercial and industrial applications where some degree of electrical inrush is expected. Type D devices have more limited applications, normally in industrial use where high inrush currents may be expected.What is a GFI breaker? ›
GFCI (Ground Fault Circuit Interrupter) circuit breakers are designed to shut off electric power in the event of a ground-fault within a fraction of a second. They work by constantly monitoring the amount of current going to and returning from equipment along the circuit.How do I know what type of circuit breaker I have? ›
Check the circuit breaker box label
Open the panel door and look for labels or markings indicating the circuit breaker type installed. The manufacturer's label will provide information on the model number, amperage, voltage rating, and other specifications (Figure 1).
Type I Circuit Breakers – Automatic Reset, which means the circuit breaker keeps cycling on and off until the overload is removed. Type II Circuit Breakers – Modified Reset or Non Cycling, where the circuit breaker doesn't reset until the overload is removed or the power is turned off.
Type D MCBs
D-rated MCBs are built for heavy-duty commercial and industrial devices where very strong current surges occasionally occur. Examples include welding equipment, X-ray machines, large motors, and uninterruptible power supply units.
For example, a type B 16A breaker will open without delay at an over current of 48A to 80A, while a type C 16A breaker will open the circuit without delay at a current value between 80A and 160A, and a type D 16A breaker between 160A and 320A.What is C breaker vs B breaker? ›
Type B devices are generally suitable for domestic applications. They may also be used in light commercial applications where switching surges are low or non-existent. Type C devices are the normal choice for commercial and industrial applications where some degree of electrical inrush is expected.What is the standard breaker for a house? ›
The standard for most household circuits are rated either 15 amps or 20 amps. An important note to remember is that circuit breakers can only handle about 80% of their overall amperage. That means a 15-amp circuit breaker can handle around 12-amps and a 20-amp circuit breaker can handle about 16 amps.How many outlets can be on a 20-amp circuit? ›
Ideally, you should spread as many outlets around your home as possible and assign them to a single circuit. Just keep in mind the maximum load for a single circuit. A good rule of thumb is to assume that there will be a maximum power draw of 1.5 amps for each outlet, allowing 10 outlets for a single 20-amp circuit.What are the two breakers on AC unit? ›
One AC, Two Breakers
Most central air-conditioner systems incorporate two circuit breakers. One protects interior components such as the air handler/blower fan inside the house. Another circuit breaker protects the outdoor condenser unit, including the compressor.
In simplest terms, a Class 2 circuit is of such low voltage and current, and therefore low power, that it does not present a shock hazard to personnel or a fire hazard. Ensuring available energy is limited provides many design, regulatory, installation, and operational benefits.What is a Class 4 circuit? ›
Class 4 circuits may be AC or DC and up to 450V peak. Class 4 circuits are constantly monitored for fault events. Despite the higher voltages, FMPS have a similar risk for fire and shock when compared to power-limited circuits because the FMPS limits the fault energy.What is a Class C circuit breaker? ›
Type C circuit breakers are used for more powerful electrical devices where any surges are likely to be higher – typically commercial and industrial environments. They are designed to trip at currents between five and ten times their rated load. Good examples include smaller electric motors and fluorescent lighting.What is a Class 3 circuit? ›
Class 3 circuits are often used for nurse call systems, public address systems, voice intercom systems, and security systems. If the power demand for circuits over 30V is over 0.5VA, but less than 100VA, you'll need a Class 3 circuit.