GEC to POCO pad mount

[shepelec]

HI all!!

The town I work for has renovated the fire station and installed a nice 600A service. The issue I am having is the engineer required a 4/0 GEC between the POCO pad mount and the main switch. The 4/0 is not in the conduits with the service entrance conductors but does bond to the UFFER and the communications tower.

I'm calling this a paralled neutral and am wanting to see it disconnected at the POCO transformer.

What say you??

Thanks
Paul

 

[kwired]

Engineer starts off by calling it the wrong name. A GEC runs from equipment to grounding electrode(s) not from equipment to equipment.

I agree all that has been accomplished is making a parallel path for neutral current.

If you had a neutral to ground bond at only one location - the transformer or the disconnect then it could possibly be called an equipment grounding conductor, and that is how it is done with separately derived systems.

 

[jbt260]

If the 4/0 conductor is bonded to the neutral in the PoCo transformer AND to the building ground electrode system, then you will have neutral current flowing through this 4/0 conductor. Recommend keeping the PoCo ground electrode system seperate from the the building ground elelctrode system. The neutral will bond the two ground systems together.

 

[shepelec]

Thanks Guys!!

Just wanted to make sure I was looking at this the right way.

The engineers felt it was a better system to run the ground out to the POCO tub and they have done this a bunch of times.:roll:

We'll see what they come back with since this is the second time I'm bringing this up to them.

Paul

 

[kwired]

Thanks Guys!!

Just wanted to make sure I was looking at this the right way.

The engineers felt it was a better system to run the ground out to the POCO tub and they have done this a bunch of times.:roll:

We'll see what they come back with since this is the second time I'm bringing this up to them.

Paul

It is parallel to the neutral and will carry neutral current. Its impedance will be raised because it is carrying current.

How/why are these passing inspection if being done that way?

 

[shepelec]

They aren't in the town I work for. I wouldn't have questioned it except they were adamant it was an accepted practice.


Paul