Is it allowed to use 3phase MSB for 1phase incomming service from utility service

[ActionDave]

Well it's an unbonded piece of the electrical system... The code does not address this so I'm not wrong. Just playing Devils advocate because technicially this bus could store charge and be a shock hazard

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What do you do with A and B phase? That's where the real shock hazzard is.

 

[kwired]

Well it's an unbonded piece of the electrical system... The code does not address this so I'm not wrong. Just playing Devils advocate because technicially this bus could store charge and be a shock hazard

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With that logic applied one should need to bond all "spare/unused" conductors one may install as well then. Then that turns into one of those endless loop problems because if they are bonded they should need to be green - which makes them unusable as spares because they can't be green once you do have a use for them:blink:

The unused bus is an intended current carrying component - it is just a spare so to speak.

 

[ggunn]

Well it's an unbonded piece of the electrical system... The code does not address this so I'm not wrong. Just playing Devils advocate because technicially this bus could store charge and be a shock hazard

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I must be misinterpreting what you are saying. If there is a neutral bonded to ground in a wye service, bonding one of the phases to ground would be... interesting.

 

[kwired]

I must be misinterpreting what you are saying. If there is a neutral bonded to ground in a wye service, bonding one of the phases to ground would be... interesting.

He is saying since the unused third bus is non current carrying metal that it should be bonded to the EGC. I think if one takes that approach any spare conductors one would ever pull for potential future use should need bonded as well.

 

[Abdel Rahman Mohamed]

The client for one of the project bought 400A-3phase-MSB and 125A-3phase panels but the utility service can provide only 1phase for this project.

Can we use this 3phase equipment for single phase service. if so can you let us know the approach of wiring it.

If we use 3phase equipment for 1phase service will there be any effect on breaker?

You can, but waste of money, only 1/3 of your breaker will be used .

 

[kwired]

You can, but waste of money, only 1/3 of your breaker will be used .

1/3 of available breaker space will not be used with many design types. Some can still use all the space - I Line is one that can .