Electrical – Is a grounded/neutral wire (not grounding wire) required to be run to a subpanel that will supply only 240V (2-pole) devices


I'm installing a subpanel that will supply only 240V 2-pole devices. I'm positive I never will need the capability to run 120V (1-pole) devices. Am I required to run a neutral wire to the subpanel? Please don't provide answers that recommend I do it "either way" for future-proofing. I only want to know what is code-required.

The code for feeders talks a bunch about the required size of feeder grounded wire, but as far as I've seen it never comes right out and states that it is required to provide a grounded wire. I am of course providing a grounding wire.

Best Answer

Its fine, no different than the main feed to your house. NEC(1999) article 200 is "grounded conductors" and 215 is "feeders".

"200-2. General. All premises wiring systems, other than circuits and systems exempted by sections ... 215-7 ..., shall have a grounded conductor that is identified in accordance with section 200-6. ..."

and so

"215-7. Ungrounded Conductors Tapped From Grounded Systems. Two-wire dc circuits and ac circuits of two or more ungrounded conductors shall be permitted to be tapped from the ungrounded conductors of circuits having a grounded neutral conductor. Switching devices in each tapped circuit shall have a pole in each ungrounded conductor."

Meaning that you need to use double pole switches and breakers. (that disconnect both wires, as opposed to common light switches that only disconnect one of the wires.)