Are ungrounded conductors of circuits with a grounded neutral allowed to tap two-wire DC or AC circuits of at least two ungrounded conductors?

• A. Yes.
• B. No.
• C. Only for DC circuits.
• D. Only if the feeder is over 1000 A.

Answer: (A)

The important idea here is that having a grounded neutral does not prevent you from tapping power off the ungrounded conductors of an existing circuit. If a circuit has two or more ungrounded conductors (the hot legs), you can derive a second circuit by tapping from those hot conductors, provided the new branch is wired safely and protected properly.

In practice, this means you must size the new conductors for its load and protect them with their own overcurrent device. The neutral and grounding must be handled correctly, and if the new branch shares a neutral with another branch (a multi-wire setup), the hot conductors feeding those branches should be on opposite phases and have a common disconnect so that a fault or overload properly interrupts both hot legs. The grounded neutral’s role is simply to provide a stable reference and fault return path; it does not, by itself, restrict tapping from the ungrounded conductors of a circuit.

This applies to both DC and AC situations, as long as there are at least two ungrounded conductors to tap from and all wiring practices and protections are followed.