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#199781 03/08/11 07:38 PM
Joined: Jan 2004
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I just had an inspector call me and he had inspected a job at a church where the handyman had replaced all the two wire receptacles with IG's (orange Dot). This an EMT job and the contractor installed a jumper wire between each receptacle green screw and the box. Inspector asked me if this is a violation? I said yes, what say you?


George Little
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110.3(B)? It is not really "IG" anymore but I am not sure that is a violation.
When I read through the articles that talk about IG, they just permit you not to bond to the enclosure (going as far back as the MBJ bus bar without a connection). I don't see anything that prohibits it.



Greg Fretwell
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George:
I have to agree with Greg. It's not an 'IG', but it is compliant with the jumper and the EMT.

The green screw ground path is via the jumper to the box & EMT, and the 'isolated' mounting yoke is bonded via the mounting screws.

I guess $$$ was not a factor for the 'handyman'?

What basis do you say it's a violation...110.3 (b)?



John
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110.3(b) for sure. When see an orange dot or an orange triangle on a receptacle a user expects he/she is using a circuit that has a isolated ground and this may be critical to the equipment being used. I like the comment about $$$ not being an issue. It's just something that is not up to my standard. I've been whacked before for winking at common sense things. Yes I know it's not a fire or shock hazard but I'm writing it.


George Little
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George:
Yes, it's your call, & 110.3 (b) is the way to go.



John
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I think IG is largely snake oil and the "standard" of what IG really means is so loose (isolated to the first panelboard or all the way back to the service disconnect?) that I am not sure how you really write it up but it is clear that there is nothing "isolated" here.

:opinion bit on:
My take on IG is "fix your box and your problem will go away". I have seen people make electricians jump through lots of hoops before they finally fix the real problem. Usually they do not admit that all of the electrician's toil was wasted effort.
A failure caused by "noise" is a symptom not a cause.


Greg Fretwell
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Greg:
Back some years IG was a 'spec' for computer equipment, as I'm sure you know. Lately, I only see it for some POS equipment.

That said, it has been a royal pain as to how to install the IG to satisfy everyone involved. I had a few way back that REQUIRED a driven grd rod in the 'spec', to which the AHJ laughed, and we 'bonded' that 'rod' to the other GEs in the facility. That job was for a 'data' rack back in the mid 70s.

Many jobs later, the kinks were worked out...and back to the main with the "IG"!



John
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IBM dropped IG as a requirement sometime in the early 80s when they figured out it was not really accomplishing anything. Unfortunately old habits die hard and I still hear people say it is required.


Greg Fretwell
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The only thing I see is 110.3 (b) too. The receptacle is installed as it is listed.

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George:
Some commentary from an article in ECM, comments by MH, only a portion of herein:

"Per the Code, the grounding terminal for an IGR could terminate to the metal outlet box that contains it (Figure, point C). The NEC doesn't dictate where you terminate the grounding terminal for an IGR just that you terminate to an effective fault current path. Nor does the NEC require each IGR to be on its own dedicated branch circuit.

However, the Code does require you to ground the metal enclosure. This is automatic with a regular receptacle; you must provide an additional grounding means when using an IGR (unless you bond the enclosure to the IGR). The Code does not permit you to use interlock, or standard, type MC cable when wiring an IGR because the outer interlock sheath is not recognized as an effective fault current path to ground metal enclosures. However, you can use AC cable with an insulated equipment grounding conductor, because type AC cable armor is listed for use as an equipment grounding conductor."



John
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