How is an AFCI different from a GFCI?

An AFCI addresses certain arcing faults, while a GFCI addresses ground faults that can lead to electric shock. Some devices combine both types of protection.

Why might an AFCI trip repeatedly?

An AFCI may trip repeatedly because of damaged wiring, a loose connection or a problem with connected equipment. An electrician can investigate the circuit and its loads.

What does the test button on an AFCI do?

The test button checks whether the AFCI's trip mechanism responds to a simulated fault. The device's instructions explain how to interpret the result.

Glossary

What Is an Arc Fault Circuit Interrupter?

An arc fault circuit interrupter is an electrical safety device that detects certain dangerous arcing patterns and shuts off power to the affected circuit. Arcing occurs when electricity jumps across a gap, such as a loose connection or damaged wire. The device helps reduce the risk of electrical fires.

Quick Facts About Arc Fault Circuit Interrupter

Category: Electrical protection device
Used for: Detecting hazardous arc patterns
Common confusion: Ground fault circuit interrupter
Also called: AFCI, Arc fault circuit breaker
Often discussed with: Electrical Code Corrections, Circuit Breaker Replacement

Key Takeaways About Arc Fault Circuit Interrupter

AFCIs respond to arc patterns, not just excess current.
A trip calls for attention to the affected circuit.
An AFCI and a GFCI address different electrical hazards.

How Arc Fault Circuit Interrupter Works

A black arc fault circuit interrupter switch with ON and OFF labels is mounted on a gray panel outdoors

An arc fault circuit interrupter monitors the electrical current flowing through a circuit. Its sensing electronics look for patterns that may point to unwanted arcing. When the device detects a concerning pattern, it trips and interrupts the current. Related service: Electrical Code Corrections.

Related glossary terms: Arc Fault, Branch Circuit, Circuit Breaker.

Some arcing occurs during normal use of electrical equipment. For example, a switch can produce a brief arc as its contacts separate. An AFCI uses its sensing circuitry to distinguish normal activity from patterns linked to a fault.

An AFCI may be built into a circuit breaker or an outlet. The breaker type sits in the electrical panel and protects the circuit it serves. An outlet type provides protection at its location and may also protect wiring beyond it.

A man uses a screwdriver to work on an electrical breaker mounted in a wooden wall

From the Electrician Pittsburgh team

When we handle electrical code corrections, we check the circuit and its existing protection. We also look at the panel and wiring connections before choosing an approach. A trip may point to a wiring issue that needs attention.

Arc Fault Circuit Interrupter in Practice: A Real-World Example

An electrical code correction involves a bedroom circuit with an older breaker. The electrician checks the circuit and panel before selecting a compatible AFCI breaker.