Find and compare quality circuit breaker box products online - load center, panelboard, main service panel, sub panel options, and electrical power distribution devices.

Circuit Breaker Box (Load Center) and Electrical Panel Board Products

How Does a Breaker Box or Load Center Work?

A circuit breaker box (also known as a load center) is the component of a residential or commercial electricity supply system that distributes electrical power into subsidiary (branch) circuits while also housing protective fuses or circuit breakers for each circuit. If an electrical short or overload occurs, the circuit breaker automatically disconnects power to prevent potential damage, electrical fires, and/or personal injury.

What is a load center or breaker box, and how is it different from a panelboard?

What is a Breaker Box Commonly Called?

The term "breaker box" is the most common name for this important part of your home's electrical system, but it is also known by several other names. The name that is used most often may vary depending on the region or country. Some other names for a breaker box are load center, electrical panel, breaker panel, main panel, service panel, circuit breaker box, fuse box, DB box, panel box, and distribution board.

How to Know if a Load Center or Circuit Breaker Meets Safety Standards?

Load centers and circuit breakers must meet certain standards and requirements per the International Electrotechnical Commission (IEC) and the National Electrical Manufacturers Association (NEMA). Elliott Electric Supply offers a variety of these products at industry standard.

Load Center
(Breaker Box)

A load center serves as a safety mechanism similar to a whole house surge protector that prevents appliance damage or fire. Typically housed in a sheet-metal enclosure, a load center is constructed with a "dead front" that prevents contact with "live" electrical parts, and is placed near the power supply in a central location.

Homeowners or electrical professionals can disconnect electrical contacts in the main breaker to de-energize circuits and safely work on wiring or outlets during maintenance or repair. Historically, these surge protection safety devices employed fuses that would require replacement after failure, but modern boxes typically use circuit breakers that can be reset without replacement. Standard trip circuit breakers are the most common in household usage and they are available with two mounting options: plug-in and bolt-on. Load centers are commonly used in residential applications and feature plug-in breakers that easily snap in and out of any available slots.
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Circuit Breaker
(Plug-in breakers & bolt-on breakers)

A circuit breaker is a switch that shields an electrical circuit from overload and/or short circuit. Once protective supplies (e.g. a protective relay) detect fault within a current, the circuit breaker will interrupt the flow so little to no damage is caused. They come with metal or molded-insulated frames, at least one toggle switch for opening and closing the current, a trip unit, and an arc extinguisher. Additionally, circuit breakers can have protective features like a ground fault.

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A panel board, or panelboard, is often found in commercial and industrial lighting with higher voltage tolerances up to 600V and with a maximum current rating of 1,200 A. They feature a larger and deeper enclosure with bolt-on breakers that attach with threaded screws.

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Subpanel Load Center
(MLO - Main Lug Only)

A subpanel load center, often main lug only (MLO) type, is a smaller electrical panel that is connected to the main service panel. It is used to distribute electricity to specific areas of a home or building, such as the garage, workshop, or outdoor areas. Subpanels can also be used to add additional circuits to a home that has outgrown its main service panel.

Subpanel load centers are typically made of metal and have a hinged door that provides access to the circuit breakers. The circuit breakers are mounted on bus bars, which are metal strips that carry the electricity from the main service panel to the subpanel.

Subpanel load centers come in a variety of sizes and ratings. The size of the subpanel will depend on the number of circuits that need to be protected, and the rating will depend on the amount of current that the subpanel can safely handle.

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What's the Difference Between a
Main Electrical Panel Box and Sub Panel?

Main electrical panel: Known as a breaker box or load center, this is the foundation of any building's electrical circuits and systems. The main electrical service panel activates, controls, and regulates power supplied by a utility company as electricity comes from the meter through service conductors to the main panel.

Sub panel: Sometimes called a satellite panel, a sub panel breaker box can be added to segment power from the main electrical panel into a separate, downstream load center. Once installed, subpanels have their own breakers and circuits that originate from a single power circuit from the main electrical panel. A sub panel board, typically a Main Lug Only (MLO) type load center, can be placed anywhere on a structure and allows electricians to safely add extra circuits without replacing the main panel. It's important to note, however, that the power / amperage demands of a sub panel cannot exceed the capacity provided by the main electrical panel, and the subpanel requires an isolated and insulated neutral bar as well as a ground bar.

What Is a Circuit Breaker?

Circuit breakers are safety mechanisms designed to prevent damage or fire resulting from an excess or surge of electrical current. With tens of thousands of fires annually resulting from electrical damage or malfunction, the National Electrical Code® (NEC) requires electrical safety features in residential and commercial construction, and circuit breakers are one of those requirements.

Molded Case Circuit Breaker

How Do Circuit Breakers Work?

A standard circuit breaker is rated by wattage and amperage, and they operate by automatically separating (breaking) electrical contacts which interrupts the flow of electricity when a fault is detected. This separation can occur via tensioned spring, compressed air, thermal expansion, or magnetic field, depending on the voltage class and type of breaker. A typical circuit breaker features a reset lever, reset button, or reset switch, and it can be found in a wide variety of settings from low-current residential circuits and appliances to high-voltage commercial, industrial, and municipal systems, depending on the rating and type. Additionally, breakers can feature single pole, double pole, or more (three or four) poles to control additional circuits that share a neutral wire for specific installations.

What are the different types of circuit breakers?

Standard circuit breakers: These are the most basic type of circuit breaker and are used to protect circuits from overloads and short circuits. They have a single switch that trips when the current exceeds the breaker's rating.

Ground fault circuit interrupters (GFCIs): GFCIs are designed to protect against electrical shock. They work by detecting small imbalances in the current flowing through the hot and neutral wires. If an imbalance is detected, the GFCI will trip and cut off power to the circuit.

Arc fault circuit interrupters (AFCIs): AFCIs are designed to protect against fires caused by arc faults. Arc faults occur when electricity arcs across two conductors that are not supposed to be connected. AFCIs can detect arc faults and trip to cut off power to the circuit before a fire can start.

Standard Trip Breaker

Standard trip circuit breakers consist of a bimetallic strip and a solenoid. The bimetallic strip is made of two metals that expand at different rates when heated. When the current flowing through the circuit exceeds a certain level, the bimetallic strip bends, triggering the solenoid. The solenoid is a coil of wire that creates a magnetic field when energized. The magnetic field generated by the solenoid pulls a lever that opens the circuit, stopping the flow of current. To reset the circuit breaker, simply push the lever back into the "on" position.

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Ground Fault Breaker
(GFCI - Ground Fault Circuit Interrupter Breaker)

A ground fault circuit interrupter (GFCI) circuit breaker features a grounded wire to protect against unwanted or unintended line-to-ground connections. These residual-current devices are designed to detect small leakage current (typically 5-30 mA) and disconnect the circuit quickly to prevent appliance damage or electrocution.

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Arc Fault Breaker
(AFCI - Arc Fault Circuit Interrupter Breaker)

Arc fault circuit interrupter (AFCI) breakers are specifically designed to detect dangerous electrical arcing and small amounts of excess current, and feature an arc extinguishing chamber. An AFCI breaker can also distinguish between incidental arcs and potentially dangerous ones.

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Dual Function Circuit Breaker (DFCB)

A dual-function circuit breaker (DFCB) is a type of circuit breaker that provides both arc-fault circuit interrupter (AFCI) and ground-fault circuit interrupter (GFCI) protection. This can save space in electrical panels and help comply with the NEC, the National Electric Code®.

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Types of Circuit Breaker by Design: Magnetic, Thermal, Molded

Circuit breakers are available in numerous construction and structural types such as Magnetic Circuit, Thermal Magnetic, and Molded Case circuit breakers.

Circuit Breaker

A magnetic circuit breaker is the most common type of breaker used in the US and is primarily used in low-current circuits (less than 100 amps). A magnetic circuit breaker is kept closed by a spring-latching mechanism that gets released by an electromagnetic solenoid when a fault is detected.

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Thermal Magnetic
Circuit Breaker

Arc Fault Breaker, AFCI  to protect against electrical arc danger

A thermal magnetic circuit breaker features bi-metal switches that can detect heat and are triggered by large overloads However, thermal magnetic breakers allow smaller overloads to persist, permitting short current spikes that are required for electric motors or other non-resistive loads. A thermal magnetic circuit breaker can also be sensitive to ambient temperature.

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Molded Case
Circuit Breaker

A Molded Case Circuit Breaker (MCCB) is used for robust residential, commercial, and industrial applications, including heavy current circuits (up to 2500 A). MCCBs protect motors, switchgear, and industrial or telecom equipment from overloads or short circuits at high amperage. Some molded case breakers can communicate trip data electronically.

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Warning: When using this information to perform electrical work, call a licensed electrician or consult the NEC® for safety. All licensed electricians have passed examinations covering the National Electric Code®, know state and local building codes, and may carry insurance to cover damages.