A long shot...

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rhamblin said:
I’m tempted to close this post as it has veered from original posting; but u guys just seem to be having so much fun. Any chance u want to fill the rest of us in?
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We are just throwing Firesign Theatre lines around. Firesign Theatre was a 4 man comedy troupe in the 60's who had a brief resurgence in the late 80's. Their media were "underground" radio stations on the US west coast and record albums. They performed live infrequently and sporadically.

Their humor was very cerebral and convoluted. We used to listen to the same recordings over and over, and we would find new nuggets on every listen. They would also do stuff like having one end of a telephone conversation on one album and the other end on another album, e.g. the wrong number call between George Tirebiter on Don't Crush That Dwarf, Hand Me The Pliers and Nick Danger on All Hail Marx and Lennon; it's only after listening to both recordings that you realize that "Nick Danger" and "Nick's Pizzeria" are on adjacent lines in a phone book, hence the wrong number dialed by George.

FT never worked "blue"; I don't remember even a curse word in any of their work.

I was (am) a huge fan.
 
Bringing us back to the electrical side of things...I got another question.

With my new employer, I was sent to another plant to start doing an Arc Fault Study. While I was looking at the 2 main switchgears, counting conduits and conductors, I noticed there was no grounding wire from the utility owned outside transformer outside, to the customer owned Square D 2500 Amp switchgear inside. This doesn't seem right? This was installed by an electrical contractor last summer. They have 8 parallel feeds of 400 KCMIL Aluminum 3 phase, then they have a 4/0 Neutral but no ground. There was a wire connecting to building steel. I didn't get a chance to verify, but I'm assuming they are bonding the neutral to the ground at the switchgear. All conduits feeding downstream of the switchgear have grounding wires.

Either way, shouldn't there be a ground going back out to the utility transformer? The conduits from the xfmr to the switchgear are run underground encased in concrete, and the xfmrs are enclosed in a fenced in area.
 
rhamblin said:
Bringing us back to the electrical side of things...I got another question.

With my new employer, I was sent to another plant to start doing an Arc Fault Study. While I was looking at the 2 main switchgears, counting conduits and conductors, I noticed there was no grounding wire from the utility owned outside transformer outside, to the customer owned Square D 2500 Amp switchgear inside. This doesn't seem right? This was installed by an electrical contractor last summer. They have 8 parallel feeds of 400 KCMIL Aluminum 3 phase, then they have a 4/0 Neutral but no ground. There was a wire connecting to building steel. I didn't get a chance to verify, but I'm assuming they are bonding the neutral to the ground at the switchgear. All conduits feeding downstream of the switchgear have grounding wires.

Either way, shouldn't there be a ground going back out to the utility transformer? The conduits from the xfmr to the switchgear are run underground encased in concrete, and the xfmrs are enclosed in a fenced in area.
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You never pull an equipment ground with service conductors. There is no reason to, the neutral, grounding electrode conductors and any equipment grounds all have to get bonded at the service disconnect. You only use a green to carry fault current back to that spot where the neutral is bonded. If you pulled a green back to the utility transformer you'd just have a parallel neutral carrying normal current.

To put it another way, from the service disconnect back to the utility transformer the grounded / neutral and equipment grounding conductor are the same conductor.
 
ActionDave said:
You never pull an equipment ground with service conductors. There is no reason to, the neutral, grounding electrode conductors and any equipment grounds all have to get bonded at the service disconnect. You only use a green to carry fault current back to that spot where the neutral is bonded. If you pulled a green back to the utility transformer you'd just have a parallel neutral carrying normal current.

To put it another way, from the service disconnect back to the utility transformer the grounded / neutral and equipment grounding conductor are the same conductor.
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And if the "green" is smaller then the "white" they are still parallel to one another but not same resistance so current doesn't balance between them either.
 
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