Branch Circuit Requirements Flashcards

A multiwire branch circuit must have a means to simultaneously disconnect which conductors at the point of origin?

Answer: All ungrounded conductors

NEC 210.4(B) requires simultaneous disconnection of all ungrounded conductors of a multiwire branch circuit.

In a multiwire branch circuit, the grounded (neutral) conductor carries what current when loads are balanced?

Answer: The difference of the phase currents

On a balanced multiwire circuit the neutral carries only the unbalanced (difference) current.

Where must the ungrounded and grounded conductors of each multiwire branch circuit be grouped?

Answer: At the point of origin

NEC 210.4(D) requires conductors of each multiwire branch circuit to be grouped at the point of origin.

The continuity of a grounded conductor in a multiwire branch circuit must not depend on which connection?

Answer: A device terminal such as a receptacle

NEC 300.13(B) prohibits relying on device terminals for neutral continuity in multiwire circuits.

Each branch circuit shall be legibly identified at the panelboard as to its what?

Answer: Purpose or use

NEC 408.4(A) requires each circuit to be marked with its clear, evident purpose.

Branch-circuit ungrounded conductors must be identifiable by which means where a premises has more than one nominal voltage system?

Answer: Phase and system identification by color or marking

NEC 210.5(C) requires ungrounded conductors to be identified by phase/system where multiple voltage systems exist.

What is the maximum number of multiwire branch-circuit ungrounded conductors that share a common neutral in a typical 120/240-volt single-phase system?

Answer: Two

A 120/240V single-phase multiwire circuit uses two ungrounded conductors sharing one neutral.