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Open Neutral?
(lemmy.world)
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this post was submitted on 28 Aug 2023
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Maybe I’m missing something but 220 doesn’t need a neutral, just 2 hots. Maybe if you were wiring up a NEMA outlet with a neutral connection that would be bad, but a direct wire to an appliance sounds fine?
This is correct. Direct connection to a 220/240 appliance takes two hots -- one each from opposite ends of the phase -- and a ground. No neutral is required. (You may even find a sticker inside the wiring panel to the effect of, "Do not connect any neutral wire." The mini split I just installed had one, for instance.)
Some people treat ground and neutral as interchangeable since in residential applications with only a single breaker panel they are often bonded at the panel anyhow. While you can get away with this in a variety of scenarios, doing so is not technically correct.
It's the same idea, except with two legs of single phase instead of 3 legs of three phase. A lot of HVAC equipment is centered around some kind of motor, and they'll typically have some kind of transformer to derive control voltage.