_____ conductors shall not be used for more than one branch circuit, one multiwire branch circuit, or more than one set of ungrounded feeder conductors except as allowed elsewhere in the Code.

• A. Neutral
• B. Ground
• C. Hot
• D. Shield

Answer: (A)

The ability to share a conductor occurs with the neutral in a multiwire branch circuit. A neutral can serve more than one circuit only when two ungrounded conductors from those circuits feed a common neutral as part of a multiwire branch circuit. The neutral carries the difference between the currents in the two hot conductors, so sharing it is acceptable under specific conditions (notably, the circuits must have a common disconnect so they are de-energized together). This is allowed because the neutral is tied to the system grounding at the service, and its sharing is carefully controlled to avoid dangerous conditions. Other conductors aren’t intended to carry current for multiple circuits: hot conductors are meant to supply a single circuit, ground conductors are for fault paths and are not used to carry normal currents across circuits, and shielding isn’t used as a current-carrying path.