while I was trying to fix a small problem in the building.The problem took me outside the building. The service is a100a 480v 3ph 4w. The have 3-1/0 and #2 ground from service disconnect no neutral from disconnect to indoor panel. Is there any code requiring a neutral with feeder to panel?
neutral from service panel
- Thread starter mannyb
- Start date
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- Location
- Connecticut
- Occupation
- Engineer
No, there is no requirement to bring the neutral from the disconnect to the panel if no loads require it.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Doesn't a 3Ø, 4 wire service require a neutral?
Kind of what I was thinking.
The name says it all, three phase 4 wire...
if it’s a three wire delta though...
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Wye or Delta, doesn't 4 wire automatically mean a neutral? Otherwise it would be a 3 wire service.
- Location
- Connecticut
- Occupation
- Engineer
Maybe I misunderstood his question, but I read it as asking about the feeder from the service disconnect to the panel, not the service conductors.
- Location
- Tennessee NEC:2017
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- Semi-Retired Electrician
That's the way I read it.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
That would make sense, it's actually a feeder not SEC's.
I agree with you. A three phase three wire service to me means a three wire delta with no neutral.
no fourth wire.
I didn’t finish my comment above. Got into a rush. That’s why a LOT of my posts have edit boxes below.
if it’s a three wire delta though, it would be a three wire service, maybe a mistype on the OP?
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Such a service does indeed have a neutral, which must be extended to at least the service disconnect, but beyond that only where a\the load requires it.
A couple of years ago, I added a second 200a panel at a residence to feed a tankless water heater, and I used an SE feeder; two lines, EGC, no neutral.
Frank DuVal
Senior Member
- Occupation
- Electrical Contractor, Electrical Engineer
Interesting discussion of terminology.
In services, three phase 4 wire indicates three hots and a neutral, the ground is made at the service panel (usually).
In branch circuits/receptacles/plugs, three phase 4 wire indicates three hots and a GROUND. To get a neutral it is a three phase 5 wire circuit.
I see three hots and a ground all the time in safety switches. I've had to pull neutrals when the next process needed 120...….:rant:
In services, three phase 4 wire indicates three hots and a neutral, the ground is made at the service panel (usually).
In branch circuits/receptacles/plugs, three phase 4 wire indicates three hots and a GROUND. To get a neutral it is a three phase 5 wire circuit.
I see three hots and a ground all the time in safety switches. I've had to pull neutrals when the next process needed 120...….:rant:
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