We have a older home in town that is being fed with single phase feeders from city owned transformer. Meter socket and panel in the house is set up 3 phase. Electrician is going to replace meter socket with on e set up for single phase. Is there anything in the code that would prohibit the use of the existing 3 phase panel in this situation?
3 Phase co-mingling with single phase
- Thread starter VIC1958
- Start date
- Status
- Location
- Simi Valley, CA
Other than you wouldn't be able to use every third space and a single phase meter won't plug into a three phase socket. Sorry reread the part about replacing the meter. So my other thought would be that he's spending more in time to jerry rig the house than it would probably cost for a new panel.
I've always contended that this...
...[indirectly] prohibits using a panel in a manner for which it was not designed.
kwired
Electron manager
- Location
- NE Nebraska
Why won't single phase meter plug into three phase socket? I know I have seen that done a time or two. Might want to make sure you don't have a wild leg on the C phase if doing this as the single phase meter will plug into the A and C positions of the socket. The cases I have seen this the socket remained in place, third phase was discontinued and center phase in the socket was not used as new owner did not need three phase for anything.
- Location
- Simi Valley, CA
Well could be an area thing. Around here we don't have any three phase in residential areas. The only three phase we have here is in commercial. All commercial three phase meters are five prong and all of our resi ones are four prong.
Oh and I would also go along with what Smart $ said too.
kwired
Electron manager
- Location
- NE Nebraska
Has nothing to do with whether or not in a residential area. Where I have seen it done was non residential, but building changed owners as well as type of occupancy and equipment used. There was no need for three phase but the socket was left in place and only phase a and c slots were used and a single phase meter plugged right into those positions.
Your three phase meter sockets are probably 7 prong not 5. 2 per phase and one for grounded conductor. I think 5 jaw meters are commonly used when metering single phase derived from a wye system (like two lines and grounded conductor of a 120/208 system).
A stand alone meter socket does not need to comply with anything in Art. 408.
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JDB3
Senior Member
- Location
- San Antonio, Texas
Back in the early 1980's, I had a house built in a rural acreage subdivision & had 3 phase service. Just felt like having it!:lol:
kwired
Electron manager
- Location
- NE Nebraska
It is not uncommon here to have three phase available on a farm, but you just don't see anyone running the third phase to the dwelling located on the farm as there is generally no need for it.
These systems are usually 120/240 three phase with wild leg. If they were 120/208 I probably would run three phase to the home if the load was high enough. You get 1.73 times more VA from same conductor size, but you also lose a little VA when going from 240 to 208 volts.
- Location
- Simi Valley, CA
Well forgeting any NEC requirements, I'm pretty sure our local POCO would have some issues with it.
Oh and someone mentioned that the code section reffered to dosen't have anything to do with stand alone meter bases. Again it's an area thing, we don't have stand alone meter bases out here, every thing is all in one.
Oh and someone mentioned that the code section reffered to dosen't have anything to do with stand alone meter bases. Again it's an area thing, we don't have stand alone meter bases out here, every thing is all in one.
kwired
Electron manager
- Location
- NE Nebraska
What is the issue, other than they want to play games and show who has control? Why is this any different than landing two phases on a three pole breaker and leaving third pole unused, or same thing with a three pole fused switch or contactor?
None at all?? I could see that being more so true for single phase services but not necessarily for three phase. What do you commonly see for metering on 200 amp 277/480 volt services. All in ones for something like that are likely pretty rare, but maybe I'm wrong. Around here those services are almost exclusively stand alone meter base and fused switch, with some POCO even wanting a disconnect on supply side of meter so it can be pulled while deenergized.
I assume ,(Yes this is dangerous) that SoCal Edison requires test bypass facilities for commercial meter cans? Ether single phase or 3?, I ask because they are required in PG&E territory & both PoCo's are under the same PUC.
- Location
- Simi Valley, CA
That's correct.
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