Correct.I think multi wire circuits require the circuit breaker to disconnect all circuits - so two devices can be on separate legs and share a neutral if its a two pole breaker.
Multiwire circuits, while common, have a few downsides:
1. Requirement for common means of disconnecto per NEC 210.7. Practically speaking this means a 2 or 3 pole common trip breaker. The neutral (grounded) conductor need not be disconnected.
2. Can't be used for emergency lighting circuits per NEC 700.10.
3. May not be suitable for high harmonic content loads like switchmode power supplies in LED luminaires.
ST
I think you'll be fine.Steve
When we redid our theatre a few years ago, we went with ETC smartpacks. Ie pulling 20 amp 3 phase feeders to various locations. My thought was that we could convert some of our feeders into three 20 amp/ 120 v circuits for LEDs in the future.
You say “May not be suitable”. Can you be more precise. IE should I plan on only getting one 20 amp circuit from each feeder if I am plugging in LED fixtures
If it matters to the discussion, I am not talking about some kind of adapter cable, but something like a lex bento box.
Thoughts?
I think you'll be fine.
Inrush current will likely be your limiting factor as to how many fixtures you can put on each 20A circuit.
ST
I was rewiring some outlets in my house and found out the hard way that was how it was wired.The trend has been to home-run all neutrals. @STEVETERRY can probably clarify if that is even allowed, I don't think so. Even in the case of relays, circuit assignment can still leave the neutral overloaded. When I was growing up, it was common to have a common neutral between two circuits provided the circuits were on opposite legs. About the only time that is done now is when you are feeding a single device (like a dryer or oven in a home.)
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