(A) The minimum requirements for service entrance conductors under this chapter shall be the same minimum requirements as set forth in the most current edition of the National Electric Code (NEC), and subsequent revisions.
(B) The conductors from the point where the service drops end, up to the service equipment, are called service-entrance conductors. Types TW, THW, RHW or any other type conductor suitable for outdoor (wet) locations may be used. They may be separate wires brought into the service-entrance weatherhead through conduit to the meter base or cables made up into a service-entrance cable approved for this purpose.
(C) Service-entrance cables are governed by the National Electric Code as follows.
(1) NEC 230-40(a). Service-entrance conductors shall be insulated.
(a) Exceptions 1, 2 and 3. Bare copper-grounded conductor is acceptable if in a raceway, or direct burial is acceptable where suitable for the soil condition, or in soil when the cable has moisture and fungus-resistant covering.
(b) Exception 4. Aluminum-grounded conductor without individual insulation or covering is acceptable if in a raceway, or direct burial is acceptable when part of the cable assembly which has a moisture and fungus-resistant outer covering and which is approved for the purpose.
(2) NEC 230-41(a). Service-entrance conductors shall have ampacity to carry loads as per NEC Article 220.
(3) NEC 230-41(b), underground conductors. NEC 230-41(b-1), (b-2). In single-family dwellings with six or more two-wire branch circuits or with an initial computed load of ten kw or more, conductors shall have an ampacity of not less than 100 amperes three-wires.
(4) NEC 230-41(b-3). Not smaller than 60 amperes for other loads.
(a) Exception 1. Not smaller than No. 8 copper or No. 6 aluminum for more than two two- wire branch circuits.
(b) Exception 2. Not smaller than No. 8 copper or No. 6 aluminum if by special permission for loads limited by demand or by source of supply, according to the town’s Municipal Electric Utility.
(c) Exception 3. Not smaller than No. 14 copper or No. 10 aluminum for limited loads of a single-branch circuit, but never smaller than the branch-circuit conductors. (See NEC 220-3b.)
(5) NEC 230-54. A maintight service head is required.
(6) NEC 230-54(c). Service heads shall be located above the service drop conductors; however, where it is impracticable to locate the service head above drops, it may be located not more than 24 inches to one side.
(7) NEC 230-54(e). Service conductors shall be brought out through separately bushed holes in the service heads.
(Prior Code, § 152.16)
NEC reference:
For calculation of wire size for allowable ampacities, see Tables 310-16 through 310-19 and Articles 220 and 220-22
Grounding electrode conductor, see Table 250-94
Service entrance conductors, see Articles 230 and 238
Service entrance equipment disconnecting means and overcurrent protection, see Article 230