in a recent nec forum discussion,someone said "technically you couldn't use a 3 ph panel on single ph service ".i understand the concept of not using something unless it's listed for the job you're doing. i have a customer who owns a storage bldg. that was previosly a lumber yard.he hopes by switching back to single ph , he can reduce the minimum monthly charge by the power co. i would like to change out the meter base,re-use the same mast,panel(which already has 120volt lts and recepts).i would just re-arrange breakers to land on phases that have power.it would save money on cost of panel and labor.would you guys go along with this from an inspectors standpoint?
3 phase panel for single phase service
- Thread starter tommyrice
- Start date
- Status
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Tommy- you have my blessings. I see nothing wrong with it but we are not the ones that have the final say so I suggest you check with your local guy.
If the meter measures kilowatts, why would it save money? Never heard of that before...
Also, in order to really have a single phase service the third leg would have to be removed from the conduit or you would have a open unprotected phase. You can't just pull out one wire, wouldn't you have to pull the whole feeder out and replace it? It seems by the time you are done with all that it would take a substantial amount of time for the investment to be paid back. Also, if you went from three phase to single, the service size would be different.
Also, in order to really have a single phase service the third leg would have to be removed from the conduit or you would have a open unprotected phase. You can't just pull out one wire, wouldn't you have to pull the whole feeder out and replace it? It seems by the time you are done with all that it would take a substantial amount of time for the investment to be paid back. Also, if you went from three phase to single, the service size would be different.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
The poco probably charges commercial rates for a 3 phase.
If the op changes the single phase meter to single phase he would pull out the extra wire- no big deal there. This is a service on the building so the wire is but a few feet-- not a feeder to the building.
Why would it be different if all the commercial equipment is gone. He stated this was a lumber yard that is now a storage building. The load is probably next to nothing.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Commercial rights are a lot more than residential rates, at least around here. I guess it depends on where you live to know how significant the difference would be.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
I hope there are no MWBC's, that would or could be a show stopper.:roll:
- Location
- Massachusetts
From an NEC perspective if I was an inspector I would not pass this citing 110.3(B) and 408.3(E).
From a personal perspective, no way. The panel is getting swapped out or they can get someone else to do the job.
BTW commercial rates per kwh are not necessarily more, sometimes they are much much less.
In this case with an apparently small load the premium paid for a 3 phase service is probably the real issue not the kwh price.
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