What is a multiwire branch circuit?

A multiwire branch circuit is defined by the presence of two or more ungrounded conductors that share a common neutral conductor. This setup creates voltage differences between the conductors, enabling the circuit to provide power to a variety of loads while being more efficient in terms of conductor material usage.

In residential wiring, multiwire branch circuits allow for the distribution of electric power to multiple outlets or devices, often using two hot wires from opposite phases of a split-phase system. This arrangement ensures that the loads are balanced across the electrical panel, preventing overloading on a single leg of the service.

Using a common neutral conductor between the phases, the circuit can provide 120V or 240V to the connected devices while ensuring that the neutral carries the unbalanced load, making it an effective way to power multiple devices.

The other options do not accurately describe a multiwire branch circuit. Identified lighting and appliance outlets refer to the end-use application of circuits rather than the relationship between conductors. A single wire supplying multiple pieces of equipment describes a different configuration known as a branch circuit, whereas a circuit connecting directly to the power supply without overcurrent protection would not meet safety regulations and is not a characteristic of a multiwire branch circuit.