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So I'm wiring up my woodshop and I've got a question about branching a 120 volt circuit off a 240 circuit.

I'm running 12/3 for this circuit coming of a 20 amp 2 pole breaker. The thought for this specific circuit would be for my dust collector and air compressor. Right now both are 120 and I'm just doing a shared neutral with one set of plugs in the box being one circuit and the other being the other circuit. Black and white to 1 set of outlets and red and white to the other.

But I was wondering if I upgrade my dust collector to one that requires 240, could I run the 240 and 120 circuit with that same 12/3? So essentially black and white to the 120 circuit and black and red to the 240?

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  • @Steven I see nothing in 210.4 that states they're only allowed within the Kitchen.
    – flycrg
    Commented Nov 6, 2015 at 17:45
  • As long as all "hot" conductors are rigged to trip together at the panel (they should be, at your double-pole breaker) and you bundle and label both "hots" with the neutral in the panel to indicate the shared neutral situation, you should be good. Commented Nov 6, 2015 at 17:47
  • @chris This is already coming out of a sub panel. But that sub panel is being fed by 6/3.
    – flycrg
    Commented Nov 6, 2015 at 18:00
  • Wait, why are you talking about using the neutral (white) on the 220vt dust collector? You need to check the dust collector specs, if it requires a dedicated grounding conductor you are out of luck sharing that with the other circuits. Commented Nov 6, 2015 at 18:15
  • @Jimmy Fix-it you're right that I wouldn't need the white on the 220. Brain fart. This would be going to either a L6-20 or a 6-20. Also the dust collector right now is 110, I'm thinking for the future since the walls will be closed up if/when that is upgraded
    – flycrg
    Commented Nov 6, 2015 at 18:24

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The NEC expressly permits 120v & 240v loads on mwbc (multi-wire branch circuit) provided both legs are disconnected at the same time. This point is moot since the same is required for just a 240v circuit.

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