Underground Service Entrance Cable Requirements

According to 338 2 there are two types of service entrance cables.

Underground service entrance cable requirements.

Meter base mounted on exterior wall of house or mobile manufactured home. For overhead service weather head must be a minimum of three feet above the roof. 5trenches to be in as straight and direct a line as possible. 4conduit minimum depth 36 inches.

Nec 300 5 underground wiring conduits and raceways direct buried cable or conduit or other raceways shall meet the following minimum cover requirements. At 18 inches you can use thwn 2 conductors inside a continuous length of pvc conduit which protects the wire all the way through the trench to the house. At 24 inches you can bury underground feeder cable using pvc conduit to 18 inches below ground only where the wire comes up. Current transformer cabinets overhead or underground service window type ct s figure 11.

Single mobile home underground service alternate meter pedestal figure 10. Cu copper. 14 2 wg 14 gauge 2 conductors with ground etc. Single mobile home underground service pressure treated post figure 9a.

12 2 12 gauge 2 conductors. 14 2 14 gauge 2 conductors etc. In general bury the nonmetallic conduits 18 inches below grade or 12 inches if protected by 2 inches of concrete or equivalent. Service entrance disconnect and location shall conform to the latest version of the nec and all local ordinances.

Conduits installed less than 36 inches in depth require cooperative engineering approval and shall beencased in concrete to cooperative specs depths specified are to finished grade. For service entrances of 201 to 400 amperes as determined by the nameplate ampacity of the service disconnect a rain tight current transformer enclosure constructed of code gauge metal with an approved mounting base for bar type current transformers shall be used. Al aluminum conductor. Single phase underground service meter installation figure 9.

A disconnecting means must be provided for all. Requirements for nonmetallic conduits nonmetallic conduits or raceways approved for buried cable give less protection than metal conduits and require greater burial depths. Direct burial cable rigid or intermediate metal conduit non metallic raceway pvc 24 inches 6 inches 18. For underground service the poured footing must be notched out for the conduit.

Any conduit crossing under a road shall be schedule 80. Minimum 6 copper ground wire securely stapled to wall.