Logo background Search

Copyright 2024 Electrical101.com All Rights Reserved.

Sitemap

Sitemap

Terms of Use

Privacy

About

Electrical 101

Bolt Bolt

Multi-Wire Branch Circuits

Question or Comment?

A multi-wire branch circuit in a residential dwelling contains two hot wires of different phases (A and B phase) and share one neutral wire as return current. When a three wire NM cable is used for this type of circuit:

See example diagrams below. Outlet ground connection diagram shown separately.

Multi-Wire Branch Circuit Correct Wiring

The neutral wires are connected together before connecting to the terminals on the left outlet. The NEC does not require the hot (black) wires to be connected together before connecting to the terminals on the left outlet.

Multi-Wire Branch Circuit Wiring Diagrams

It is preferred that the hot (black) wires be connected together before connecting to the terminals on the left outlet, even though it is not required by the NEC.

Multi-Wire Branch Circuit Preferred Wiring Diagram

Multi-Wire Branch Circuit Incorrect Wiring

The neutral wires are not connected together before connecting to the outlet on the left. The two left outlets do not meet the NEC for a multi-wire branch circuit. If the neutral wires are disconnected with B phase power turned on, the neutral wire from the B phase outlet has line voltage.

Multi-wire Branch Circuit Correct Wiring Diagram Multi-wire Branch Circuit Preferred Wiring Diagram Multi-wire Branch Circuit Incorrect Wiring Diagram