Single phase panels in 3ph-fed residence

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Open Neutral

Senior Member
Location
Inside the Beltway
Occupation
Engineer
In a large residence with some 3-ph loads, such as pool pumps, HVAC, shop tools.... must all the breaker panels be 3-phase?

Or could those feeding the ordinary 120V lighting, utility outlets etc. be run-of-the-mill 120/240 ones; off 2 of the phases? There would be multiple such panels and we could stagger such to balance the loading/phase.

Reason is the electrician called out a significant cost difference in the panels.
 

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
There is nothing in the NEC that says you can't do what you describe. And being an EE I'm sure I don't need to remind you that you will only have 208V in these 1? panels.
 

Open Neutral

Senior Member
Location
Inside the Beltway
Occupation
Engineer
Thanks... Yes, it's 208/120Y. [We have one deep well pump that's 480 & we'll need a step-up there.]

We're well aware of the 208 vs 240. The cooktop is some exotic induction thing; it's OK. The oven we can buy 208. The dryer, ditto.

All this depends on the dollars making sense; most of them are in the megadollars to PG&E to get 3ph, and the solar gear, but there's always a bottom line.
 

iwire

Moderator
Staff member
Location
Massachusetts
In a large residence with some 3-ph loads, such as pool pumps, HVAC, shop tools.... must all the breaker panels be 3-phase?

Or could those feeding the ordinary 120V lighting, utility outlets etc. be run-of-the-mill 120/240 ones; off 2 of the phases? There would be multiple such panels and we could stagger such to balance the loading/phase.

Reason is the electrician called out a significant cost difference in the panels.


Not a problem at all and in fact it is quite common in multi-unit apartment buildings, three phase service with single phase feeders.
 
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