Safe de-energizing of pad mount transformer - grounds required?

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I^2R

Member
Location
NH
Had a situation recently where we needed a 2,000A 480V service de-energized by the PoCo so we could work on the service entrance switch gear.
The PoCo intended on shutting off the transformer using the internal hotstick switch in the pad (not a visible opening) and calling it good. Our policy requires personnel protective grounds to be applied. Eventually, they installed the grounds, however they were not happy about it as it required pulling the load breaks, calling another truck that had a grounding elbow kit, etc.
They also laughed at our 40-cal arc suits we used to verify the service de-energized.
I would certainly not trust the switch. Same goes for the switch on a pole mount transformer.
Thoughts? How do you handle this?
 

Buck Parrish

Senior Member
Location
NC & IN
We do our thing, the poco does theirs. Some times they're real helpful, some times their not.
I've had pretty good luck talking with poco engineers. You have to give them some days notice of what you plan or would like to do.
 

wbdvt

Senior Member
Location
Rutland, VT, USA
Occupation
Electrical Engineer, PE
If you are looking for a visible break, I would think either the riser fuse cut outs open or the primary elbows pulled and put in the parking stands would suffice. You can then check for dead on the secondary spade terminals and apply grounds.

I can understand them laughing with your 40 cal suits as their PPE for the pad mount transformers secondary is 4 cal per the NESC.
 

kwired

Electron manager
Location
NE Nebraska
I can see the switch on a pole mount xfmr. It is real easy to see that it is open or not.
Exposed switch ahead of the transformer yes, internal switch with external operating lever - all you can see is which position the lever is in, can't tell if contacts are open.
 
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