Section 43.33. Electrical circuits

(a) Any completely insulated feeder circuit in excess of 24-kilowatt-capacity leading underground, if the potential does not exceed the limits of a medium voltage potential, shall be provided above ground with a switch and an automatic overload circuit breaker. In the case of ground return direct current circuits, a switch and circuit breaker shall be installed in the underground side of the circuit but may be omitted from the return side. Fuses may be substituted for circuit breakers in circuits.

(b) Any high voltage alternating current feeder circuit leading underground shall be provided above ground with an oil break switch on each phase and every switch shall be equipped with an automatic overload trip.

(c) Any branch shall be provided with a switch of ample carrying capacity on each phase within 50 feet of the point where it leaves the main circuit.

(d) Wires for all lighting circuits shall be covered with an insulation adequate for the voltage of the circuit. Unless encased in pipes or other metallic covering, wires shall be strung on porcelain or glass insulators. Separate encased wires shall be kept at least three inches apart except where they enter the fittings. Metallic casings, if used, shall be efficiently grounded.