You can install electrical electrical cables outdoors for running pumps, lighting, and other appliances. Whatever the purpose, you can run the wiring overhead or into an underground trench. If you choose a trench, you will need to know what types of wiring and conductors they can use and how deep to bury them. Here are six tips on electric wire burial.
1. Direct burial by cable
UF cable (underground power cable) is specially designed and manufactured with properties that make it ideal for burial. This wire should be buried to a depth of 24 inches. The streamer is less likely to be cut or disturbed by a typical excavation if it is far below the ground. However, it is shallow enough that digging the trench is unlikely to cut water or electrical pipes.
When purchasing UF cable, you need to take special care to differentiate it from normal NM (non-metallic or Romex) cable. UF cable typically has information printed on the sheathing that identifies it as UF.
2. Using the UF cable above the ground
Although UF cable is designed to be buried, you can also use it above ground. For example, if you have a cable that is partially buried and partially above ground, and without the need to splice your burial cable to a length of cable above ground, you can use UF cable for the entire cable. However, keep in mind that any UF cable used in above-ground applications must run through conduit where it can be damaged.
3. Electrical cable enclosed in PVC conduit
The National Electrical Code (NEC) sets the required burial depth of electrical cable in rigid non-metallic conduit, such as PVC, at 18 inches. Cable in any conduit, including PVC, that is buried at this depth is not in danger of being cut or disturbed by normal excavation. Keep in mind, however, that no cable or conduit is protected against excavation by construction equipment such as trench excavators or backhoes.
4. Electrical cable in rigid metal conduit
Due to the durability of rigid metal conduit, electrical cable may enter this conduit at a shallower depth. According to the NEC, you can enter as low as 6 inches.
5. Electrical cable encased in flexible metal conduit
If you want to use flexible metal conduit, make sure it is the watertight type.