AFCI Outlets and Breakers Explained

Date Published: April 17, 2024

Electricity is one of the most important components in our homes. However, it can also be one of the most dangerous. A flawed electrical system can be the source of power outages, property damage, bodily injury, and even house fires. Thankfully, through modern technology, we are able to implement safeguards into our electrical systems in order to prevent these types of accidents. One example of these safety devices is the AFCI. This device is instrumental in preventing safety hazards caused by arc faults.

Arc Fault Circuit Interrupters are a crucial aspect of any residential building, but unlike their counterpart, GFCIs, AFCIs are less talked about and more misunderstood. So let’s dive into the world of AFCIs.

AFCI on electrical breakers

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What is an Electrical Arc?

In order to explain an AFCI, we must first discuss what an electrical arc is. An electrical arc is a discharge of electric current across a gap in a circuit. Because the air is a poor conductor, the current is able to make its way across the gap by generating an ionized column of gas called a plasma. The plasma creates a bright light and extremely high levels of heat. Arcing is often utilized in a controlled manner for things such as welding, plasma cutting, and lighting.

But when arcing occurs unintentionally, it can be very dangerous. They have been known to cause fires, electrocution, and even explosions. Damaged, frayed or kinked wires, gaps in wire insulation, improperly wired panels, accumulated dust or corrosion can all cause arc faults.

Electrical Arc

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Electricity will often try to find the path of least resistance. So if anything is interrupting its intended path (through electrical wiring or connection), it can jump to another conducting material, such as a metal component in an electrical panel. Even if the arc fault is occurring along the current’s intended wiring, the heat that it generates can break down the wire insulation and cause an electrical fire. These fires can then grow and spread to other flammable components of the house. In some cases, these fires will occur behind walls or other hidden areas, causing the fire to intensify significantly before even being detected.

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What is an AFCI?

So while they happen infrequently, arc faults are definitely something we need to avoid – especially in the residential setting. So how do we do that? In comes the AFCI, or Arc Fault Circuit Interrupter.

The Arc Fault Circuit Interrupter’s name pretty much sums it up. The device uses specialized technology that will allow it to detect any abnormal arc occurring along the circuit. When it does, it will interrupt the circuit so that no current can be transmitted through it. By promptly interrupting the circuit upon detecting abnormal arcing, AFCIs can prevent the arc from escalating into a fire. This proactive approach significantly reduces the risk of fire-related incidents.

This is such a crucial aspect of the home that the current National Electrical Code (NEC) now requires that an AFCI be installed on each circuit of the home. On occasion, these devices will be installed at electrical receptacles, but they are more commonly installed at the circuit breaker.

AFCI diagram


Do not get the AFCI confused with its close relative, the Ground Fault Circuit Interrupter (GFCI). Both devices are designed to “break” the circuit, but they are triggered by different conditions. As its name suggests, a GFCI will trip the moment it detects a ground fault.

A ground fault occurs when electricity flows to an unintended, grounded conductor, such as a water source or a human body. This is a serious shock risk near water sources, which is why GFCIs are required in all bathrooms and kitchens.

GFCIs are most commonly installed at the outlet receptacle (as shown above). But they can also be installed at the circuit breaker on individual circuits. In those cases, all the outlets on the circuit will have GFCI protection.  On the contrary, AFCIs are almost exclusively installed at the circuit breaker.

Both AFCIs and GFCIs can be installed on the same circuits together. They work as a team to provide the maximum protection that a circuit can have.

Inspecting for AFCIs

Electrical is one of the primary components we inspect when conducting our standard inspections. This is generally one of the main safety concerns for most of our clients. We conduct a very thorough inspection, examining the main panel, testing outlets, fixtures, light switches, and even smoke/CO detectors.

We know the important role the AFCIs play in the home – not to mention they are a code requirement. So our inspectors always make sure to inspect for them. We will test them when possible, but we often can’t when the home is occupied with outlets in use. If there are any missing or defective AFCIs, we will be sure to recommend immediate evaluation and repair.

If you are based in Colorado and in need of inspection services, Scott Home Inspection would love to be of service! With over 18 years of home inspection experience in the CO Front Range, we ensure that you will find the highest quality service in the industry from our inspectors and office staff.

To learn more about us, visit us online or contact us today.

Inspection of electrical panel AFCI breakers

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About the Author: Chris Kimmel

Chris Kimmel worked as an Associate Home Inspector for two years, handling numerous services including sewer scope inspections, pest inspections, mold air sample testing, radon testing, and water quality testing. Chris now works with Scott Home Inspection as a Content Writing Specialist.

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    Joey April 24, 2024 at 10:21 am - Reply

    This is a fantastic explanation of AFCI outlets and breakers! Understanding the difference between AFCI and GFCI protection is incredibly helpful for homeowners. The breakdown of how AFCI technology works to prevent arc faults is clear and informative.

    Since AFCI protection is now required in most areas, do you recommend having existing electrical systems inspected to identify any outlets or breakers that might need to be upgraded to AFCI compliance?

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