Feeder & Ground

[mstrlucky74]

If you have a 3" w/4 #350mcm...would the 4th wire be the neutral? My question is could you have a feeder that only has phase conductors and a neutral and not a ground?

 

[Dennis Alwon]

If you have a 3" w/4 #350mcm...would the 4th wire be the neutral? My question is could you have a feeder that only has phase conductors and a neutral and not a ground?

It is possible that the conduit is the equipment grounding conductor however if it is plastic pipe then the feeder would need an equipment grounding conductor. You will see 3 phase with an equipment grounding conductor and no neutral- that is common

 

[mstrlucky74]

It is possible that the conduit is the equipment grounding conductor however if it is plastic pipe then the feeder would need an equipment grounding conductor. You will see 3 phase with an equipment grounding conductor and no neutral- that is common

so what would you say the 4th conductor is in my example above? Thx

 

[Dennis Alwon]

so what would you say the 4th conductor is in my example above? Thx

In your case I would say it's a neutral since the wire is sized too large to be an equipment grounding conductor.

 

[Shoe]

Not sure you can say what the conductor is intended to be without more information:

- Is this a service entrance feeder? If so, then that is probably the grounded conductor.
- Is the conduit metallic? Then that may serve as the equipment grounding conductor.
- What does this feeder serve? It could be an oversized equipment ground conductor for a few reasons: did the contractor run out of other size conductor and just pull the same size? Or does this feeder serve a sensitive piece of equipment that has a limited tolerance for ground resistance? (sensitive medical imaging comes to mind)

The best way to figure it out is to open up the enclosure that this feeder terminates to and see what it's being used for.

 

[Dennis Alwon]

Not sure you can say what the conductor is intended to be without more information:

- Is this a service entrance feeder? If so, then that is probably the grounded conductor.
- Is the conduit metallic? Then that may serve as the equipment grounding conductor.
- What does this feeder serve? It could be an oversized equipment ground conductor for a few reasons: did the contractor run out of other size conductor and just pull the same size? Or does this feeder serve a sensitive piece of equipment that has a limited tolerance for ground resistance? (sensitive medical imaging comes to mind)

The best way to figure it out is to open up the enclosure that this feeder terminates to and see what it's being used for.

The OP said it was a feeder- given that and the size of the conductors being all the same I think it is a good bet that the conductor is a neutral. Even as a service entrance it would be a neutral since no equipment grounding conductor is installed for a service. Of course, you cannot be 100% sure without more info.

 

[infinity]

I'm with Dennis 3? and Neutral. Although it can be designed as such, 99% of the time you would not pull in an EGC the same size as the phase conductors.

 

[mstrlucky74]

I'm with Dennis 3? and Neutral. Although it can be designed as such, 99% of the time you would not pull in an EGC the same size as the phase conductors.

Thanks

 

[qcroanoke]

I'm with Dennis 3? and Neutral. Although it can be designed as such, 99% of the time you would not pull in an EGC the same size as the phase conductors.

We do it all the time on some UPS systems we install. right there in the manual w/ an equipment ground the same size as ungrounded conductors.