What is the minimum cover requirement for type UF cable supplying power to a 120V, 15A GFCI-protected circuit outdoors?

The minimum cover requirement for type UF (Underground Feeder) cable used to supply power to a 120V, 15A GFCI-protected circuit outdoors is indeed 12 inches. This depth is necessary to protect the cable from physical damage and to ensure safe operation when buried.

Type UF cable is often used for outdoor lighting and power circuits because it is rated for direct burial. The National Electrical Code (NEC) specifies different burial depths depending on the type of cable, its use, and the environmental conditions. For UF cable in a residential setting, 12 inches is the standard depth for buried installations to help safeguard against accidental damage from lawn care activities or seasonal changes.

This specific requirement helps maintain safety, ensuring that underground installations do not pose a risk of electrical hazard or injury. The other choices exceed the minimum depth significantly, which, while it may not be harmful, is not necessary and can lead to unnecessary complications or excessive labor costs during installation.