In which environment must arc-fault circuit interrupters be primarily used?

Arc-fault circuit interrupters (AFCIs) are primarily designed for residential installations to enhance safety and reduce the risk of electrical fires caused by arc faults. These devices are specifically engineered to detect unintended electrical arcs that can occur in wiring and appliances. By doing so, they provide critical protection in environments where the risk of fire due to damaged or deteriorating wires is significant, such as in homes.

The National Electrical Code (NEC) mandates the use of AFCIs in many residential areas, particularly in bedrooms and living spaces, to safeguard against these potential hazards. The development of AFCIs centered around the fact that many household fires start due to faulty wiring or appliances, which these devices effectively mitigate.

In contrast, other environments like commercial and industrial installations have different requirements and considerations based on their usage and risk factors. While certain types of ground fault protection may be integral in those settings, the specific focus on arc-fault protection is less emphasized. Outdoor electrical installations may involve other forms of protection against moisture and environmental conditions, rather than the unique requirements addressed by AFCIs in residential applications.