Pedestal service grounding

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Wirenut 1166

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I have a customer that is replacing his electric gate operator. He is feeding it from a disconnect on the building. They ran triplex overhead from the existing building (Across the parking lot)to a utility pole. On the pole they set a sub-panel and drove a ground rod. From that point they ran 220-volts with a neutral and a ground. The new gate motor needs 220-volt with a neutral and a ground. My question is am I reguired to replace the triplex with quad plex and ground the system back to the service. As always I appreciate all you advise.
 
Re: Pedestal service grounding

Check out 250.32(B)(2)

This deals with two structures fed from the same service.

Chris
 
Re: Pedestal service grounding

IMHO........Do you need a neutral? use the triplex as the two hots and ground.

If you do need a neutral you need quad cable, isolated neutral and grouind bars in the disconnect and get rid of the ground rod.

Jim
 
Re: Pedestal service grounding

Jim, read the aforementioned section.

Roger
 
Re: Pedestal service grounding

Good question, I trying to look up a code reference to back me up. I failed.

I still believe in what I said regarding the ground, neutral and quad cable, but I overlooked 250.32(B)(2) as stated earlier.

I lower my head in shame...........
 
Re: Pedestal service grounding

Reading this section it sounds like I can leave the tri-plex and use the bare wire as the neutral. At the utility pole I will make sure the ground and N are seperated and the ground rod is good. I always thought I needed to carry the ground all the way back to the service ground, but I guess I learned somthing today. Thanks for your help
 
Re: Pedestal service grounding

BY wirenut: At the utility pole I will make sure the ground and N are separated and the ground rod is good.
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NOOOOOOOOOOOOOOOOOOO!!!!!!!!

When you use the exception in 250.32(B)(2)
You must bond the neutral or you will not have any fault path back to source!!! Earth is of too high of resistance to fault a short circuit!

This is from 250.32(B)(2):
The grounded circuit conductor is the neutral, it is one in the same.
the grounded circuit conductor run with the supply to the building or structure shall be connected to the building or structure disconnecting means and to the grounding electrode (s) and shall be used for grounding or bonding of equipment, structures, or frames required to be grounded or bonded.
Click to expand...

[ November 02, 2005, 12:48 AM: Message edited by: hurk27 ]
 
Re: Pedestal service grounding

Since you are installin a 'sub-panel' in an out building you still need 4 conductors because you need 2-hots, a neutral and a ground and you cannot bond the 2 in the sub-panel.

Correct?
 
Re: Pedestal service grounding

Jmd, the answer is no, you do not need four conductors if 250.32(B)(2) applies.

Roger
 
Re: Pedestal service grounding

I have a three wire triplex (Bare is the neutral)feeding the sub-panel...The sub-panel (Main lug) is grounded with a ground rod. From the sub-panel they are running a 4-wire two hots one neutral and a ground to the gate. If code does not allow the earth as the only ground how do you ground a pedestal service in the middle of a yard?

Thanks again for all the great advice.

Hurk-Thanks for your input that does make since.
 
Re: Pedestal service grounding

Roger,

I've read and re-read 250-32(B)(2) until my eyes bled............

And it boils down to the twisted verbage that "Where an equipment grounding conductor is not run with the supply..........."

That is how you can get away with a triplex vs. a quad cable, correct?

Jim
 
Re: Pedestal service grounding

Jim, if there are no other conductive paths (water pipes, conduit, phone wires, etc...) between the buildings or structures, a triplex can be used and the new panel (or disconnect) will be treated as if it were a new service.
The neutral will be bonded to the GEC and the enclosure.

Roger
 
Re: Pedestal service grounding

Originally posted by Wirenut 1166:
If code does not allow the earth as the only ground how do you ground a pedestal service in the middle of a yard?
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The answer to this question is you use a main bonding jumper in the pedestal and bond the grounded conductor to the grounding conductor per 250.28.

You also need to establish a grounding electrode system at the pedestal.

You would treat the pedestal like any other service. :)

Chris
 
Re: Pedestal service grounding

By Wirenut: The sub-panel (Main lug) is grounded with a ground rod
Click to expand...
Just make sure there is a main bonding jumper installed at the sub panel. all grounding at the sub panel must be connected to the grounded conductor (neutral) for fault path back to source.
 
Re: Pedestal service grounding

Let me see if I can provide a Code paper trail to answer the question.
Sections 250.32(A), 250.50, and 250.32(B). Section 250.32(B)(2) states in part there were an equipment grounding conductor is not run with the circuit conductors and there is a grounded conductor run to the?disconnect, treat it like a service and connect the grounded conductor to any existing grounding electrodes, and if there aren't any, use the made electrodes to establish a grounding electrode system and bond the noncurrent carrying components to it.
 
Re: Pedestal service grounding

Originally posted by roger:
Jmd, the answer is no, you do not need four conductors if 250.32(B)(2) applies.

Roger
Click to expand...
Unless you're in WA state where WAC 296-46B-250 applies. :( WAC 296-46B-250-032 reads:

Two or more buildings or structures.

(1) Effective August 1, 2003, an equipment grounding conductor must be installed with the circuit conductors between buildings and/or structures. A grounded conductor (i.e., neutral) is not permitted to be used in place of a separate equipment grounding conductor between buildings and/or structures.
 
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