The Ultimate Guide on Circuit Breakers

What Are Circuit Breakers – The Ultimate Guide

The circuit breaker is a vital safety feature of residential and commercial properties. Without circuit protection, homes and businesses would be at constant risk of fire or equipment failure caused by a current overload or power surges.

This article provides information and insight into the types of circuit breakers, their features, and their best applications for fire prevention and circuit overload.


What Is a Circuit Breaker?

A circuit breaker regulates the electricity throughout a home or business. True to their name, circuit breakers automatically break the electrical flow in the event of a circuit overload or fault. Circuit breakers eliminate the danger of fire and damage to appliances caused by circuit overload.

A circuit breaker is a circuit protection device that serves the same function as its older cousin, the fuse. A fuse is a thin metal wire with a sealed encasement that allows charge to flow through the circuit. When the fuse heats past an acceptable level, it disintegrates and cuts the circuit before damaging the electrical wiring or appliances. The disadvantage of a fuse is that it is only good for single use.

Conversely, circuit breakers operate with a switch that resets after deployment. Generally speaking, circuit breakers have a lifespan of roughly 30 years, making them a more desirable alternative.


Circuit Breaker Components

There are five universal components to a circuit breaker, regardless of its application. These include:

Frame – The outer casing that protects the circuit breaker’s working components. Depending on its application, the frame is fabricated from composite resin, glass polyester, or thermoplastic material.

Operating mechanism – This refers to the apparatus that opens and closes the circuit breaker. Depending on its application, the mechanism operates manually, automatically, or on-demand.

Contacts –The contacts connect the circuit with the current and electrical system.

Arc extinguisher – An arc happens when an electrical current separates the contacts. The energy and heat caused by the arc formation are potentially dangerous. The electrical current determines the size and intensity of the arc when the contacts are separated. True to its name, the arc extinguisher manages or extinguishes the arc caused by open circuit breaker contacts.

Trip unit – Activates the operating mechanism in the event of a short circuit or current overload. The operating mechanism opens the circuit should an overload or ground fault occur. An open circuit will not transmit an electrical current.


How Do Circuit Breakers Work?

A power grid distributes electrical current to your home or business through the circuit breaker unit, which divides the current into multiple circuits. Each circuit has a corresponding breaker to protect it from overload. If too much power comes through the circuit, the breaker shuts it off to prevent property damage or fire. In short, the three functions of circuit breakers are to monitor, protect, and switch off when necessary. 


Circuit Breaker Types

There are several types of circuit breakers. Their current carrying capacity and breaking capacity determine their use and application. The three primary circuit breaker types are (1) standard circuit breakers, (2) ground fault circuit interrupters (GFCIs), and (3) arc fault circuit interrupters (AFCIs).

Beyond these three categories, the voltage capacity of circuit breakers determines their application. Low-voltage circuit breakers are commonly used in homes and businesses. Medium-voltage circuit breakers work well in an industrial environment, while high-voltage circuit breakers can withstand the demands of power grids. 

Standard Circuit Breakers

Standard circuit breakers are best suited for home use, monitoring the power flow of home appliances. In the event of a short circuit or power surge, standard circuit breakers shut off to protect equipment from damage or fire. Single-pole standard breakers provide 120 volts to a circuit; double-pole breakers to 240 volts.

GFCI Circuit Breakers

Ground fault circuit interrupter breakers shut down power in the event of a line-to-ground fault, overload, or short circuit. Municipal codes often require GFCI circuit breaker installation in home areas with running or standing water, such as bathrooms, kitchens, basements, and garages.

Arc fault circuit interrupter breakers are mostly used for home applications to manage a wide range of unwanted electrical surges or arcs and aids in fire prevention.

Low-Voltage Circuit Breakers

These circuit breakers have a wide application in residential, commercial, and industrial settings. There are two types of low-voltage circuit breakers: 

Miniature circuit breakers (MCBs) – Designed to handle currents under 100 amps, MCBs are well suited for residential and commercial applications.

Molded case circuit breakers (MCCBs) – Designed to manage electrical currents as high as 2,500 amps, MCCBs are more robust and best suited for industrial or high-power home applications.

Medium-Voltage Circuit Breakers

voltage from 1,000 to 72,000. 

High-Voltage Circuit Breakers

High-voltage circuit breakers handle applications with voltage exceeding 72,000 volts and are well suited for power transmission cables. These circuit breakers use a variety of methods to extinguish the arc, including carbon dioxide, oil, vacuum, air blast, and, more recently, sulfur hexafluoride.

Magnetic Circuit Breakers

Magnetic circuit breakers use electromagnetic technology to manage electrical current. The electromagnet, also known as a solenoid, creates a dynamic magnetic field that adapts to the strength of the current. If the current surpasses the allowable limits, the magnetic field flips the breaker switch and cuts off electrical power. 

Magnetic circuit breakers mitigate damage caused by power surges and spikes. One disadvantage is that they are less effective in monitoring surges just below the limits of the breaker, resulting in overheating, damaged circuitry, and fires.

Thermal-Magnetic Circuit Breakers

Thermal circuit breakers protect circuits from the low surges where magnetic circuit breakers fall short. These circuit breakers employ heat and a dual metallic strip to gauge and manage electrical current. The strip bends and expands in reaction to its strength. When the current grows too strong, the strip breaks the circuit.

Magnetic-Hydraulic Circuit Breakers

The solenoid technology behind hydraulic magnetic circuit breakers allows for precise tripping in the severest temperatures.


How to Install Circuit Breakers

When properly cared for, circuit breakers have a lifespan exceeding 30 years. However, a malfunctioning breaker requires immediate attention. 

Replacing a circuit breaker is not complicated, and the breakers themselves are reasonably affordable. If you choose to take on this project, it is crucial to understand what you are getting. Replacing a breaker involves removing the safety cover and servicing the main panel. You run the risk of shock if you are not careful.

Required Equipment and Materials

  • Flashlight

  • Safety glasses

  • Screwdrivers

  • New circuit breaker


Take the following measures to safely and properly install new circuit breakers.

  • Be sure you have the correct size and type of circuit breaker.

  • Turn off each circuit breaker one by one.

  • Shut down the power main—it is the large switch near the breaker panel. 

  • Using a screwdriver, remove the panel that covers the breakers. 

  • Gently loosen the wires and pull them from the breaker casings.

  • Gently remove the breaker.

  • Line up the replacement breaker and press it into place. 

  • Attach the wires to the terminal screws and reattach the cover.

  • Turn on each circuit breaker individually, followed by the power main. 

  • To check your work, simply turn on appliances, lights, or outlets.


Choosing the Right Circuit Breaker

The load capacity of the circuit is what determines the amp size of the breaker. For everyday application, the maximum exposure for circuit breakers is 80 percent of the total amperage. 

Fortunately, most household appliances have labels indicating the required amperage. Large household appliances such as ovens, washing machines, and air conditioners have a designated circuit. If you have any questions regarding the correct circuit load for your application, consult a professional electrician.

Be mindful of the brand of the circuit breaker. Although some are interchangeable, most brands are not. Replacing one model of circuit breaker with another is potentially dangerous. It may also nullify the warranty on your panel and lead to a failed electrical inspection. Check the door of your breaker panel for brand and manufacturer information.


Contact ESD to Get Help with Buying the Correct Circuit Breakers

The technology behind circuit breakers is robust yet fragile. The smallest misstep can lead to disastrous consequences. If you have questions regarding circuit breaker installation or electrical wiring, it is crucial to enlist the services of a certified electrician. 

For assistance in selecting the correct circuit breakers for your home or business, contact Electrical Supply Distribution, LLC. With 10 years of professional experience and an excellent customer satisfaction rating, ESD provides the highest quality electrical services and carries a sizable inventory of the best quality products in the industry. 

For assistance with circuit breakers and all your electrical needs, contact the experts at Electrical Supply Distribution. Call us today at (425) 419-4167.