sub panel w/out nuetral?

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I personally think it is a good idea to label the panel to indicate that there is no neutral. The next guy that comes in to add a circuit will appreciate the advanced warning.
 
Where I worked for many years, the distance from the main substation to the building distribution was such a great distance that we had nothing but 480 volt 3 conductors. Where the feeders entered the building we would go to a DP panel and distribute out to either a 480D/480-277Y transformer for lighting loads or a 480D/208-120 panel for other loads.

The cost of the addition of the DP panels and transformers was offset by the cost of the neutral conductor and voltage drop.
 
jmd445 said:
First of all..........if he can't figure it out, he has no right being in the panel........
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I disagree-- many people may see spares in the panel and run their cable to it only to open the panel and then find there is no neutral. This happened to me in a residential job but fortunately there was another panel close by.
 
Not much makes me more frustrated than to open a single phase panel to find no neutral, unless it also has only the min sized wire for the existing load. Just makes me sick to have to explain to a customer that the previous electrician did a minimum instal. They can't quite figure out who took, or is taking them to the cleaners.

Reason I have seen so many neutrals tied to an EG or enclosure.

PP planning or engineering all around.
 
Don't forget about the poor engineer who may be doing field work and can't physically "open" the panelboard :cool:

Label label label label label label.

Any future engineer that has to work in the building will thank you.... unless you mislabel something... then we'll just swear and complain even more! :D
 
ptonsparky said:
Not much makes me more frustrated than to open a single phase panel to find no neutral, unless it also has only the min sized wire for the existing load. Just makes me sick to have to explain to a customer that the previous electrician did a minimum instal. They can't quite figure out who took, or is taking them to the cleaners.
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Tom, I think you are being harsh-:) I have wired single phase panels with no neutrals simply because the panel was for the heating and a/c. No neutral needed and there were 2 other panels- one nearby- that could have been used for neutral connections. My point is there is nothing wrong with it but labeling it would be a nice touch.

BTW, that house burned to the ground--:grin: seriously- it did but not because of the wiring. I got to wire it all over again.
 
jusme123 said:
Panel Label
480 v panel
3 phase
3 wire
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That label would indicate that you can't use "slash" rated breakers and that you would have to use the more expensive 480 volt rated breaker. The supply system is still a 480/277Y and "slash" breakers are permitted even though the grounded conductor has not been run to the panel. Maybe the first line should read "480/277Y"
 
don_resqcapt19 said:
Maybe the first line should read "480/277Y"
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I wouldn't cause adding the 277 says to me that you can get a 277 circuit out of the panel, which you can't with no neutral present. With no neutral, all the breakers would have to be 2 or 3 pole anyway.

And speaking to an earlier point, in my designs I always try to size things/provide spares as to not screw over the next guy to work on it. Cause with a lot of the clients the company I'm with works with, it could be me back there again quite easily.
 
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bluesmoke...oops said:
I wouldn't cause adding the 277 says to me that you can get a 277 circuit out of the panel, which you can't with no neutral present. With no neutral, all the breakers would have to be 2 or 3 pole anyway.
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I agree with bluesmoke. A 480Y volt 3 phase panel without a neutral does not provide 277 volts. It is true that it would read 277 volts to the EGC but the EGC is not used as a current carrying conductor under normal conditions. You cannot use single pole breakers in this type of installation because you cannot feed any 277 volt equipment. You can use single pole breakers, with identified handle ties, to feed 480 volt equipment.

"Grounding Conductor, Equipment (EGC). The conductive
path(s) installed to connect normally non?current-carrying
metal parts of equipment together and to the system grounded
conductor or to the grounding electrode conductor, or both.

Informational Note No. 1: It is recognized that the equipment
grounding conductor also performs bonding.

Informational Note No. 2: See 250.118 for a list of acceptable
equipment grounding conductors."

You will still be able to use 480Y/277 rated circuit breakers according to 240.85 because your voltage to ground is still only 277 volts.
 
jusme123 said:
Panel Label
480 v panel
3 phase
3 wire
Click to expand...

I agree with jusme123. This is the proper label for the panel. A label which says 480Y/277 means a Neutral is present in the panel, which in the case of this installation, it is not.
 
The fact that you do not provide the grounded conductor at the panel does not change the fact that the panel is a 480/277Y panel. That is based on the system that supplies the panel and not on the conductors that you run to the panel. The rest of the label tells you that there is no grounded conductor at the panel.
480/277Y
3 phase
3 wire
If the person looking at that label does not understand that there is no neutral in the panel, than that person is not qualified to work on that panel.
 
don_resqcapt19 said:
The rest of the label tells you that there is no grounded conductor at the panel.
480/277Y
3 phase
3 wire
If the person looking at that label does not understand that there is no neutral in the panel, than that person is not qualified to work on that panel.
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Amen

Roger
 
taylorp said:
I agree with bluesmoke. A 480Y volt 3 phase panel without a neutral does not provide 277 volts. It is true that it would read 277 volts to the EGC but the EGC is not used as a current carrying conductor under normal conditions. You cannot use single pole breakers in this type of installation because you cannot feed any 277 volt equipment. You can use single pole breakers, with identified handle ties, to feed 480 volt equipment.

"Grounding Conductor, Equipment (EGC). The conductive
path(s) installed to connect normally non?current-carrying
metal parts of equipment together and to the system grounded
conductor or to the grounding electrode conductor, or both.

Informational Note No. 1: It is recognized that the equipment
grounding conductor also performs bonding.

Informational Note No. 2: See 250.118 for a list of acceptable
equipment grounding conductors."

You will still be able to use 480Y/277 rated circuit breakers according to 240.85 because your voltage to ground is still only 277 volts.
Click to expand...

Handle ties would not be permitted here. 480v devices would be required to trip together.
 
lakee911 said:
Handle ties would not be permitted here. 480v devices would be required to trip together.
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That is correct only where the 2011 code is in use. The 2008 code permits the use of single pole breakers with handle ties on a 480/277Y system to supply line to line loads. 240.15(B)(3)
 
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