No Neutral at Generator - 480/277 system w/ 1-phase loads?

[winnie]

As I understand the original post, the utility provides 480/277V wye service.

The loads are 480V HVAC, 480V sewer pump, a 480V : 208/120V transformer, and 2 480/277V panels serving L-N loads.

A neutral conductor is required from the source to power the L-N loads. I suspect that the original installation used a single conductor for both neutral and EGC, possibility not code compliant.

Jonathan

 

[augie47]

There are 480 volt line to neutral loads.
"and two separate 480V sub panels full of 1-pole light circuits."
I am not aware of any way to supply 480 volt lighting loads from single pole breakers without a neutral.

One day I will take remedial reading

 

[don_resqcapt19]

I was just making that point. Any of those 1 pole loads prove 277V connections, thus neutral, thus a neutral from the generator is required. As you said. But you said 480V, which gets people confused.

I said 480 volt panel with one pole breakers.

I have never seen a 480Y/277 volt panel ever called anything other than a 480 volt panel, and I just use the terms from the original post.

 

[Seven-Delta-FortyOne]

That’s what I was wondering, if the 480/208 xfmr was customer owner, after the service point.

 

[don_resqcapt19]

That’s what I was wondering, if the 480/208 xfmr was customer owner, after the service point.

I can't see a utility permitting you to have a 480 volt service and a 208 volt service, so I have to assume that the step down customer owned.

 

[fastline]

I said 480 volt panel with one pole breakers.

I have never seen a 480Y/277 volt panel ever called anything other than a 480 volt panel, and I just use the terms from the original post.

"
There are 480 volt line to neutral loads.
"and two separate 480V sub panels full of 1-pole light circuits."
I am not aware of any way to supply 480 volt lighting loads from single pole breakers without a neutral.
"
Verbatim. You can't see how that is confusing? At least where I am from, those are 277 lights, not 480, because they have 277 going to them.

 

[don_resqcapt19]

You can't see how that is confusing?

No, I cannot see how that would be confusing to anyone that has knowledge of electrical systems. Nothing even suggests to me the light are 480 volts. It is a 480 volt panel with single pole breakers and that is automatically a 277 volt circuit, except in the rare case of a corner grounded system, where it would be a 480 volt circuit..

Edit to add:
Maybe it is a regional thing. Around here, other than on drawings, that panel will always be called a 480 volt panel. It will be called 480Y/277 on the drawings, but not in the field.

 

[fastline]

No, I cannot see how that would be confusing to anyone that has knowledge of electrical systems. Nothing even suggests to me the light are 480 volts. It is a 480 volt panel with single pole breakers and that is automatically a 277 volt circuit, except in the rare case of a corner grounded system, where it would be a 480 volt circuit..

Edit to add:
Maybe it is a regional thing. Around here, other than on drawings, that panel will always be called a 480 volt panel. It will be called 480Y/277 on the drawings, but not in the field.

Around here, regardless of any AHJ, code, etc, etc, we generally just define the voltages because it just makes sense. Per your own response, "except in" is enough for me. Sorry we don't call 277 lights 480 lights. Even on drawings and build sheets, everything is defined on voltage so we don't have that "except in" cases where someone gets to say "uh, but I thought".

Anyway, not busting balls here, just never once heard someone refer to 277 lights as 480 since you can very obviously have 480 single phase.

 

[don_resqcapt19]

just never once heard someone refer to 277 lights as 480 since you can very obviously have 480 single phase.

I have not seen anything in this thread, posted by me, or anyone else that said the lights were 480 volt lights. Everything says that the lights are fed via single pole breakers in a 480 volt panel.

That is not even remotely close to saying the lights are 480 volt lights.

Yes, you can have single phase 480 volt circuits, but again except in the very rare case of a corner grounded system, single phase 480 requires 2 pole breakers.

 

[fastline]

I have not seen anything in this thread, posted by me, or anyone else that said the lights were 480 volt lights. Everything says that the lights are fed via single pole breakers in a 480 volt panel.

That is not even remotely close to saying the lights are 480 volt lights.

Yes, you can have single phase 480 volt circuits, but again except in the very rare case of a corner grounded system, single phase 480 requires 2 pole breakers.

Don, we apparently just have a disconnect as I apparently read your own words "there are 480V line to neutral loads" very differently than you. I just find it confusing as the lights don't operate at 480V, but let's just kick the can as "please mark the damn conductors so I can figure it out when I get onsite".

Yeah, when we do panels local, we 100% mark them as 480/277, clearly indicating they have a neutral, which helps in quick troubleshoots. Otherwise they get a 480 3P ONLY.