Underground Feeder & Branch-Circuit Cable (Type UF)

Type UF looks a bit like flat NM but its conductors are encased in a solid, moisture-resistant molded jacket rather than a loose paper-wrapped fill. That construction lets it be buried directly in the earth, which is why it feeds detached garages, well pumps, yard lights and other outdoor loads.

UF still needs the burial depths from Article 300 and usually GFCI protection for outdoor circuits. Sunlight-resistant versions can be run exposed outdoors, but standard UF isn't a substitute for service cable and its solid jacket makes it noticeably harder to strip than NM.

When it applies

Type UF is your friend for outdoor and damp-location runs — a buried feed to a shed, a post light, a pump or a landscape circuit. Its jacket resists moisture and sunlight and it is rated for direct burial, so it can go in the trench without a conduit in many cases.

Common mistakes

• Not burying it deep enough — check the required cover for the circuit type and whether it is protected by a GFCI.
• Confusing UF with plain NM (Romex) and running indoor cable outdoors where it will fail.
• Stripping that tough jacket carelessly and nicking the insulation on the conductors underneath.

In the field

When I run UF out to a garden light, I lay a little slack in the trench and mark the path so the next person with a shovel knows something is down there. That extra loop lets the cable move with the soil instead of pulling tight on the connections.