When must arc-fault circuit interrupters be used according to the NEC?

Arc-fault circuit interrupters (AFCIs) are specifically required by the National Electrical Code (NEC) to be installed in dwelling unit bedrooms and living areas to reduce the risk of electrical fires caused by arcing faults. These areas are particularly vulnerable because they often contain electrical devices and outlets related to personal living spaces, where the risk of unintentional damage to wires or cords—which can lead to arcing—tends to be higher.

By mandating the use of AFCIs in these specified locations, the NEC aims to enhance safety and protect residents from potential electrical hazards. The technology enables the breakers to detect and react to arcing conditions, thereby interrupting the circuit before a fire can ignite.

In contrast, the other options either include places where AFCIs are not mandated (like warehouses and garages, which do not typically require AFCIs under the NEC) or incorrectly state that AFCIs are necessary in all commercial buildings and kitchens, where different safety devices or standards may apply.