wirebender
Senior Member
- Location
- North Central Texas
Is there anything in the NEC that would prohibit the use of the high leg to supply a single phase load such as a water heater?
High leg on single phase load
- Thread starter wirebender
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Don't think so, at least as long as it is on the right kind of breaker, but why would you want to?
Last edited:
texie
Senior Member
- Location
- Fort Collins, Colorado
- Occupation
- Electrician, Contractor, Inspector
I might add, do not it to supply a 120/240 load such as a dryer.
wirebender
Senior Member
- Location
- North Central Texas
Poor design on a main distribution panel.
There are not any slots left to get 240 volts without using the B phase.
texie
Senior Member
- Location
- Fort Collins, Colorado
- Occupation
- Electrician, Contractor, Inspector
While you can do this, keep in mind how the transformer bank in your case is built as they are not tyipcally designed for full load on the high leg. If you load up a service like this with all 240 1 phase load balanced across all 3 phases in some cases you may overload the transformer.
wirebender
Senior Member
- Location
- North Central Texas
thanks
You mean a load that is single phase that uses two hots on 208V but you use a single breaker on a high leg system with a neutral?
texie
Senior Member
- Location
- Fort Collins, Colorado
- Occupation
- Electrician, Contractor, Inspector
I hope not. I think we are all thinking the OP has a 1 phase 240 (240 only, no neutral) load that he wants to connect between high leg and 1 other leg. Can't do your method, and I wish I could tell you where in the NEC this is prohibited-not sure it is there.
wirebender
Senior Member
- Location
- North Central Texas
240v load see post #5
- Location
- Illinois
- Occupation
- retired electrician
I don't think there is anything in the code that says you can't use it line to neutral for a 208 volt load. I know it is not a good electrical practice, but I don't think the code says you can't.
I think the problem lies in trying to do so with a single pole breaker with a 208 v rating.
(assuming one is not using a 277v panelboard)
- Location
- Illinois
- Occupation
- retired electrician
Yes, the OCPD could be an issue, but that is not a direct restriction on the use of the high leg for line to neutral loads. (I could always use a fuse for the OCPD)
Do they even make a single pole 240 volt breaker?
I looked in the SQUARE-D book but couldn't find a breaker that is rated for 208V. What is the rating of breaker that is used on 277V lighting?
Breaker issue aside, Will the load work if it was designed for 2 pole 208V but it is connected to single pole 208V?
277 volt. Problem is a 277 volt breakers are not designed for installation in a 240/120 panel.
If you happen to have a 480/277 panel on the 240 system, you could use a SP 277 breaker.
My understanding is it will in fact "work", but it is not recommended from a transformer distribution standpoint.
I don't understand. If it is designed for 277 why can't it be used on lower voltage? I assume it is listing issue?
- Occupation
- Licensed Electrician
You can. The voltage is not the issue. The well tailored hound has it right.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
That is the issue as Augie stated. A panel loaded with 277 volt SP CB's on a 240/120 volt, 3?, 4W Delta system would work.
:lol::lol::lol:
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