Services, Feeders, Branch Circuits Flashcards

What is the minimum ampacity required for a service entrance conductor supplying a single commercial occupancy with a calculated load of 175 amperes?

Answer: 175 amperes

Service conductors must have an ampacity not less than the calculated load per NEC 230.42.

Per NEC Article 230, how many sets of service entrance conductors are permitted to supply a single building from a single service drop?

Answer: Up to six sets under specific conditions

NEC 230.40 permits up to six sets of service entrance conductors from a single service drop or lateral under defined conditions.

A commercial feeder supplies a panelboard with a total computed load of 92 amperes. What is the minimum conductor ampacity allowed?

Answer: 92 amperes

Feeder conductors must have an ampacity not less than the load they supply per NEC 215.2(A).

What NEC section governs the minimum size of branch circuit conductors for general lighting loads?

Answer: NEC 210.19

NEC 210.19 specifies the minimum ampacity and size of branch circuit conductors.

A 120/240V, single-phase service for a commercial building requires a grounded (neutral) conductor. Per NEC 230.42, the neutral must have an ampacity of at least:

Answer: The full unbalanced load

The grounded service conductor must be sized to carry the maximum unbalanced load per NEC 220.61.

Which wiring method is NOT permitted for service entrance conductors installed inside a building?

Answer: Open wiring on insulators through a dry area

Open wiring is not a recognized wiring method for service entrance conductors inside a building under NEC 230.43.

For a 208Y/120V, 3-phase, 4-wire feeder with a computed load of 115 amperes per phase, what is the minimum ampacity for each ungrounded feeder conductor?

Answer: 115 amperes

Feeder conductor ampacity must not be less than the computed load on each conductor per NEC 215.2.