What function does an AFCI protection device perform when it detects an arc fault?

An Arc Fault Circuit Interrupter (AFCI) protection device is specifically designed to detect unsafe electrical arcing conditions that can lead to electrical fires. When it identifies an arc fault, which occurs when there is an unintended discharge of electricity between conductors, it initiates a critical safety response by de-energizing the circuit. This action interrupts the flow of electricity, effectively stopping the potential for the fire to start.

The function of the AFCI to de-energize the circuit is essential for preventing potential hazards associated with these arc faults, as these can occur in damaged or frayed wires, loose connections, or within appliances. This proactive measure helps enhance safety in residential and commercial electrical systems.

In contrast, the other options, such as sounding an alarm, completing the circuit, or displaying a warning light, do not represent the primary function of an AFCI. While it is true that some electrical devices may have additional features like alarms or indicators, the critical and definitive action taken by an AFCI upon detecting an arc fault is to cut off the electrical supply to eliminate the risk of fire.