Unit substaion ground, what's wrong here?

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donny baker

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What's wrong with this picture, from a 12470/480V delta unit substation? I say a bolted lug can't be used on the ground bus. Thanks.

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donny baker said:
It's aluminum
Click to expand...

If it is a tin plated aluminum lug (stamped something like AL9CU), then it is acceptable for copper connections.

I wonder if this is the grounding electrode conductor for the 480Y/277V secondary?
 
Exactly, good question. First, I probably should not write my queries as though I stand behind them 100%. See, I was given a power quality / grounding report; stating these lugs weren't "UL 467 for grounding", I believe meaning tin plated bronze. I have not seen the install up close, I suspect they might have stainless bolts too. My original comment about grounding lugs can't be used - well I didn't really believe it either, but that's what the report said, and I'm not a PE, and I don't have a copy of UL 467, and all I can point to is pictures or diagrams to refute the report. What can I do?
 
Where is there any requirement that grounding hardware actually be evaluated to UL467? or, rather, where is the requirement that only UL467 hardware be used for termination of the grounding electrode conductor?
 
Job specifications should have been written to set standards, when other references are incude by nmber only it is my expierence FEW if ANY electrical contractors have them and if they do have the specs they do not read them.

SPELL IT OUT IN THE SPECS (I know you did not write the specs), before you get to this portion of the project. In lieu of that obtain the literature for the job you are being paid to do.
 
I have no objection with the connection to the ground bus. (Although the lug looks a bit large for the wire size.)

I do have a problem with the connection to the ground rod. I know it's likely "listed" but my experience with that type of fitting is to never use them. Those cheap plated screws don't hold up over time and I don't see them as making a good connection. Better to use the cast fitting with the large bolt. IMHO.

RC
 
donny baker said:
What's wrong with this picture, from a 12470/480V delta unit substation? I say a bolted lug can't be used on the ground bus. Thanks.
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Click to expand...


Why not? Its bolted to the ground rod on the other end.

My quibble might be why is there just one ground rod?
 
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