Ground Fault On A Delta

acrwc10

[quote=Eddy Current;566328]Glad to see you have a good sense of humor



No, the neutral is bonded to the tranny case and that's as far as it goes. The tranny is fed using a metal conduit which is bonded back in the electrical room.



Yes, all unenergized metal is bonded to an EGC. The electrical room is small but has two seperate feeds from the vault. One 600v delta and one 120/208 wye. Both of these systems look like they are bonded to the same EGC.
I will be back there next week to intall the GF lights so I will bring my camera, give you a better picture of what I'm dealing with.


quote]

So if I read this correctly, Your 600 volt system HAS the XO on the output connected to an earth ground and the transformer case and all metal piping is grounded to that? Is this the way it is wired ?

Because if it is you don't have a floating delta. You just have a straight delta that isn't using the neutral for utilization equipment.
Is the XO on the 600 volt connected to anything ?

Eddy Current

No, the 600v system comes from the vault which only Hydro can access. I got three wires in a metal pipe, 600v Delta


Sorry, let me re-phrase. Both systems have all their unenergized metal bonded to the same EGC.

acrwc10

Here is another link , it is not exactly about the issue you have but it really has some good diagrams to help visualize the fault path on an ungrounded system.
http://www.cooperbussmann.com/pdf/b9...b2b664f5ca.pdf

millert2

Intermittent ground fault

Just a hunch but I would look at 600 volt lighting.
Is the building or parking lights on a photo cell or timer?
If the ballast in the lights is shorted to ground you wont see it if the lighting contactor is not energized
And it is a code requirement to have ground fault indication on a delta system.
good luck.

JumboJack

Being that this happened in January,it would be a safe bet that he has figured it out..

__________________
in texas with framing and cornish people will do it for 3.00 a foot. What do yall think about that? Just laber

Bubbles

Hey. Don't leave us hanging like this. What happened? I have blueballs now.