(A) National Electric Code (NEC) Table 310-13 identifies acceptable types of underground service entrance cable. Underground feeder and branch circuit cable shall be an approved type UF cable in sizes No. 14 copper, or No. 12 aluminum or copper-clad aluminum through No. 4/0.
(B) Provisions as set forth in NEC Articles 339-1(a) (b), 339-2, 300 through 300-5, and sections 310-13, 240-3 and 310-12(c) concerning installation of underground feeder and branch circuit cable shall be applicable.
(C) In addition to the insulated conductors, the cable shall be permitted to have an approved size of insulated or bare conductor for equipment grounding purposes only. The overall covering shall be flame- retardant, moisture-, fungus- and corrosion-resistant, and suitable for direct burial in the earth.
(D) The underground service is the chosen option of the customer. A weatherproof fused switch or breaker must be installed on the feeder end of the cable before going underground (Rule 32, Utility Company Rules). Underground service cost shall be paid by the customer; however, overhead service cost may be deducted as this is normally furnished by CMEU when the underground cable and fixtures are purchased by CMEU for the customer.
(E) Service-entrance underground installation. The underground service installation is covered by National Electric Code requirements.
(1) Service lateral conductors shall be insulated.
(a) Exceptions A, B and C. Bare copper-grounded conductors are acceptable if in a raceway, or direct burial is acceptable where suitable for soil conditioning, or in any soil when cable has moisture and fungus-resistant covering.
(b) Exception D. Bare aluminum- grounded conductors are acceptable if in a raceway, or direct burial is acceptable if in a cable with moisture and fungus-resistant covering.
(2) Conductors shall have sufficient ampacity to carry the load. Service laterals shall not be smaller than No. 8 copper or No. 6 aluminum, except for limited loads; and not smaller than No. 12 copper or No. 10 aluminum for limited loads.
(3) When the service lateral conductors are installed by the electrician, the installation must conform to NEC 230-48 and 230-49, which refer to the protection of the conductors against damage and the sealing of underground conduits where they enter the house. NEC 230-49 refers to 300-5, which covers all situations relative to underground wiring.
(4) A minimum 200 ampere service entrance installation is required for all underground services (Rule 32, Utility Company Rules). The trench, service conductors and equipment, except the meter base, shall be furnished and maintained by the customer.
(5) A trench depth of 24 inches minimum is required, as in NEC Table 300-5. The bottom of the trench must be free of loose or projecting stones and debris, and backfill shall be sand or screened earth free of stones and sharp objects for the first six inches above the conductor, as explained in NEC Article 300-5(F).
(6) (a) The line conduit shall be two inches minimum, galvanized steel or P.V.C.-approved for the use (Type 80), as explained in NEC 300-5(i).
(b) It shall be securely installed with a threaded collar and nut at the bottom of the meter base to a minimum depth of one foot below ground level, as explained in NEC Table 300-5.
(7) Conductors shall be 2/0 copper or 4/0 Al with insulation suitable for underground installation, as explained in NEC Article 310-13. Conductors shall be installed in the meter base and trench to the base of the service pole by the customer. The customer’s conductors, conduit and weatherhead will be installed on the pole by the town’s Municipal Electric Utility. The customer has the option of purchasing wire and material from the town’s Municipal Electric Utility at cost.
(8) If trenching is done by the customer, it shall be his or her responsibility to call the excavation in at telephone number 962-9090 for the cable locating service.
(Prior Code, § 152.18)