Generator neutral to ground

Merry Christmas
H

hhsting

Senior Member
Location
Glen bunie, md, us
Occupation
Junior plan reviewer
Since previous thread was about the customer owned transformer and neutral to ground bond in the fire pump controller/ATS, I created new thread about generator neutral to ground bond question so its not confusing.

I have fire pump controller/ATS with 3 poles that has neutral to ground bond. The fire pump controller/ATS feeds only the 3 phase fire pump. One side is fed from customer owned transformer and the backup side is feed from emergency generator that supplies only the three phase fire pump.

The generator is outdoor 240 feet away from fire pump room where fire pump controller/ATS is. Generator brings 3 phase conductors and one ground to the fire pump controller/ATS.

Should the generator have neutral to ground bond as shown in the attachment or not?

8379471e7d7352a62b473c5b8e839911.jpg
 
ron said:
I would put the N-G bond at the customer owned transformer and the customer owned generator, and NOT bring a neutral to the ATS via the feeders and save conductor and headaches.
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Unfortunately customer owned transformer is existing and it supplies existing swbd that has SBJ so cant put SBJ at the existing transformer
 
wwhitney said:
Why not? The customer owns the transformer and SWBD, so existing violations can be corrected.

Cheers, Wayne
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Says its not within scope of work the existing swbd they would have remove sbj and reinstall at existing customer owned.

Our electrical chief also says it is safer to do sbj at swbd then have electrician go to transformer that has primary medium voltage 13.8kv.
 
hhsting said:
Says its not within scope of work the existing swbd they would have remove sbj and reinstall at existing customer owned.

Our electrical chief also says it is safer to do sbj at swbd then have electrician go to transformer that has primary medium voltage 13.8kv.
Click to expand...
I wouldn't be surprised if you went to look at the customer owned transformer and see a factory strap on the X0 - Gnd
 
hhsting said:
Says its not within scope of work the existing swbd they would have remove sbj and reinstall at existing customer owned.
Click to expand...
Eh, if it's required because the existing violation impacts the new work, that answer doesn't fly.
hhsting said:
Our electrical chief also says it is safer to do sbj at swbd then have electrician go to transformer that has primary medium voltage 13.8kv.
Click to expand...
If the feeder from the transformer to the ATS is new work, they are going to have to go into the transformer anyway to install that, so they can install an SBJ there at the same time.

So what exactly is existing, and what exactly is the proposed new work?

Cheers, Wayne
 
wwhitney said:
Eh, if it's required because the existing violation impacts the new work, that answer doesn't fly.

If the feeder from the transformer to the ATS is new work, they are going to have to go into the transformer anyway to install that, so they can install an SBJ there at the same time.

So what exactly is existing, and what exactly is the proposed new work?

Cheers, Wayne
Click to expand...

Your right i told exact same thing that they are going to have to touch transformer anyways they have to connect the fire pump conductors.

New work is the fire pump and its circuit from existing customer owned transformer secondary wye windings 480/277V.
 
hhsting said:
New work is the fire pump and its circuit from existing customer owned transformer secondary wye windings 480/277V.
Click to expand...
What about the generator and the circuit from the generator to the fire pump? Also new work? And does the generator have OCPD at its location?

Cheers, Wayne
 
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