Does my service or feeder have to have the neutral conductor if my loads are 208V?

[unsaint34]

A novice question here. I was tackling 220.61. The permitted reduction for cooking equipment and dryer got me thinking. Those loads do not need a neutral wire. Before getting into the permitted reduction on the neutral wire, why do I even need the neutral wire to begin with?

If my loads are all phase-to-phase loads and do not need the neutral wire, why do I even need a neutral conductor in my service or feeder (from a 120/208y power source)?

 

[Cavie]

A novice question here. I was tackling 220.61. The permitted reduction for cooking equipment and dryer got me thinking. Those loads do not need a neutral wire. Before getting into the permitted reduction on the neutral wire, why do I even need the neutral wire to begin with?

If my loads are all phase-to-phase loads and do not need the neutral wire, why do I even need a neutral conductor in my service or feeder (from a 120/208y power source)?

Your dryer got a light in it??? Is the motor 110 volts. Enquiring minds want to know!

 

[ptonsparky]

If your loads are all phase to phase you do not need a neutral for the operation of the equipment or appliance. You do need an equipment ground. You do need the grounded conductor, if available, for the proper operation of protective devices in case of ground faults.

 

[unsaint34]

I realize that the appliances do need 120v. But I still don't get why the neutral load is basically same as the entire load of the appliances, not just the 120V part. Thanks for your reply anyway.

 

[Dennis Alwon]

I realize that the appliances do need 120v. But I still don't get why the neutral load is basically same as the entire load of the appliances, not just the 120V part. Thanks for your reply anyway.

The neutral does not need to be the same size as the ungrounded conductor but in residential work NM cable is used so it would be hard to reduce the neutral. The neutral also much be as large as the egc in case of a ground fault.

 

[kbsparky]

I realize that the appliances do need 120v. But I still don't get why the neutral load is basically same as the entire load of the appliances, not just the 120V part. Thanks for your reply anyway.

It isn't. Neutral loads are calculated separately. Things like ranges, dryers, etc are figured based on 70% of calculated load.

Have you read section 220.61?

 

[don_resqcapt19]

...
If my loads are all phase-to-phase loads and do not need the neutral wire, why do I even need a neutral conductor in my service or feeder (from a 120/208y power source)?

On a service the grounded conductor is the fault clearing path and 250.24 requires that if the system supplying the service is a grounded system then the grounded conductor must be run to the service disconnect(s). The code does not require a grounded conductor for a feeder. With a feeder the EGC is the fault clearing path.