This is not how you do isolated ground ....

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petersonra said:
I am not sure I see anything for sure wrong with what they did code wise.
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Really? Separate ground. If a fault to ground occurs the path back to source is through the concrete rebar, to path of least resistance. Maybe to the ground rod. How soon would the breaker trip? May never trip. Let's see how long it takes to melt the breaker.

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I figured it was a 250.30 grounding electrode connection.
250.64(E)(1) requires bonding, like a grounding bushing.
 
brantmacga said:
This particular brand is hardcore about having the IG on POS equipment. We always have to sign an affidavit at the end of the job to say it's correct and to their specs. We'll end up with about 50 receps total in 4000 sq ft of restaurant.

Most others have moved away from it, as it is really no longer needed with modern equipment. A couple of other restaurant brands we build also require it, but not to the level of the store pictured above.


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We had one client that asked for something like that. We told that that the only way we would do it, is if they gave us a letter directing us to make an installation that was both unsafe and a code violation. They would not do that, so we made the install per the code requirements for an "isolated ground".
 
Daniel malack said:
Is the separate ground bar attached to the other ground bar on left side of panel ? What bar is the egc from main panel connected to?

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It doesn't look like it.
This type of install is usually the result of an electrical contractor that's not purposely trying to do something wrong.
It generally that they simply don't know any better.


JAP>
 
Cow brought that up in an earlier post about it being incapable of clearing a fault if it came down the IG.


JAP>
 
Fulthrotl said:
wow. failed to grasp the concept, eh?

the reason you want an isolated ground back to
the MAIN ground bus is to prevent ground loops,
that might bias solid state devices and cause madness.

but grounding all the devices to a point completely
different than the service ground virtually guarantees
a ground loop.

you can't fix stupid.
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Yet the equipment (especially more modern equipment) apparently works even if there are ground loops.

rcarroll said:
There is an equipment ground pulled in with the feeders.
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The feeder EGC lands on the EGC bus bolted directly to the cabinet. The left "neutral bus" which has all the "IG" conductors landed on it, has had it's jumper to the right neutral bus removed and is insulated from the EGC and the cabinet. All that connects to it is the "IG" conductors and the ground rod.
 
If we're going to pick it apart why are all of the 1p breakers on A phase only?

JAP>
 
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