Motor load without neutral

[m sleem]

Can i supply 3 core cable without neutral to a 3 phase Y motor load? this is a client request,

I think no as Per 250.24(C), am i correct?

 

[winnie]

All motors that I've encountered do not require a neutral connection to function. The motor might be internally connected in 'wye' but is supplied with only the three phase conductors, no neutral conductor.

If the _load_ requires a neutral for whatever reason, then you must provide that neutral conductor. But I would be very surprised if a 'motor load' actually requires the neutral.

Article 250 is about grounding, and 250.24 is about bonding the grounded conductor; relevant for the service but not for supplying an individual load. In addition to the 3 phase conductors, your motor load will require and EGC.

-Jon

 

[ActionDave]

Can i supply 3 core cable without neutral to a 3 phase Y motor load? this is a client request,

I think no as Per 250.24(C), am i correct?

The answer is yes. That is the only way to do it. A wye or star motor just describes the way the motor is wired internally or configured in the make up box, it has nothing to do with the circuit powering it.

 

[augie47]

250.24(C) refers to bringing the neutral to the service. There is no requirement to bring neutrals to individual pieces of utilization equipment such as motors unless required by the equipment.

 

[StarCat]

Although they are not very common, I have worked on Fan Powered Boxes that have 277V Single phase PSC motors.

 

[ActionDave]

The only single phase 480V motor I have ever seen was on a piece of refrideratire equipment

 

[m sleem]

Assuming that voltage surges are not balanced, don't we need a neutral?

 

[ptonsparky]

No.

 

[Besoeker3]

All motors that I've encountered do not require a neutral connection to function. The motor might be internally connected in 'wye' but is supplied with only the three phase conductors, no neutral conductor.

If the _load_ requires a neutral for whatever reason, then you must provide that neutral conductor. But I would be very surprised if a 'motor load' actually requires the neutral.

Article 250 is about grounding, and 250.24 is about bonding the grounded conductor; relevant for the service but not for supplying an individual load. In addition to the 3 phase conductors, your motor load will require and EGC.

-Jon

I have noted that ground and neutral are sometimes confused with each other.

 

[ptonsparky]

I have noted that ground and neutral are sometimes confused with each other.

Unfortunately.