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Discussion Starter · #1 ·
Where would an inspector get an idea in his head the an IG receptacle circuit had to have a green with yellow striped insulation for the isolated ground ? I've looked at 250.146 (d) but didn't know if I was missing something somewhere. Or if it's a common spec but not code.
 

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I'm guessing that he's thinking of cable assemblies that include an EGC and an IG conductor where the added IG is often yellow-striped.



But even there I don't know of anything requiring that color coding, and you could swap the functions of the two grounding conductors as long as your were consistent throughout your installation.
 

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There's no code mandate for it, it's just what is typically done. That's how I do 'em.

Ask him for a code reference. In fact, ask all inspectors for code references when they pull stuff out of their ass.
 

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Discussion Starter · #4 ·
erics37 said:
ask all inspectors for code references when they pull stuff out of their ass.
I politely told him there was no such code and he'd have to educate me in writing if he wanted it changed.
 

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250.119
Individual conductors shall have an outer finish of green or green with yellow stripes as permitted in this section...
I think you kinda misunderstood.

We know that insulated EGCs need to be certain colors, but the OP is referring to isolated ground circuits. His inspector is saying it is required to have green w/ yellow stripe (and it is typically done that way) but the NEC doesn't mandate it.
 

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bigger question is where would someone get the idea you need an isolated ground:jester:

Just politely saying.
Where noise can be a problem on an audio system where the design minimum ambient is south of 30 dBm.

Where SMPS artifacts on UL approved devices impress noise below 200 Hz.

Where single ended audio outputs are converted to balanced lines.
 

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Where noise can be a problem on an audio system where the design minimum ambient is south of 30 dBm.

Where SMPS artifacts on UL approved devices impress noise below 200 Hz.

Where single ended audio outputs are converted to balanced lines.
If a properly installed IG (where the IG runs isolated all the way back to the service neutral) corrects these problems, isn't that evidence of other, bigger issues elsewhere in the system, and the IG is just a bandaid?
 

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Where would an inspector get an idea in his head the an IG receptacle circuit had to have a green with yellow striped insulation for the isolated ground ? I've looked at 250.146 (d) but didn't know if I was missing something somewhere. Or if it's a common spec but not code.
In Canada, there is a code for that. Not sure about the US, but it should pretty much be the same.
 

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I believe if you have a EGC and an IG in the same raceway, enclosure, etc., there should be an identification difference. Norm as stated would be a yellow ID. If it's not an issue, just do it.
 

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Where noise can be a problem on an audio system where the design minimum ambient is south of 30 dBm.

Where SMPS artifacts on UL approved devices impress noise below 200 Hz.

Where single ended audio outputs are converted to balanced lines.
There is no evidence that an isolated ground helps with any of that.
 

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Where noise can be a problem on an audio system where the design minimum ambient is south of 30 dBm.

Where SMPS artifacts on UL approved devices impress noise below 200 Hz.

Where single ended audio outputs are converted to balanced lines.
NOPE, and did I say NOOOOOOOO.

Not when the AC distribution is properly installed.

And I have corrected problems at TV stations, Radio, recording studios, video recording studios, telecom centers, data centers, hospitals and a slew of others.
 

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I'm guessing that he's thinking of cable assemblies that include an EGC and an IG conductor where the added IG is often yellow-striped.



But even there I don't know of anything requiring that color coding, and you could swap the functions of the two grounding conductors as long as your were consistent throughout your installation.
I have never seen an American cable with yellow striped conductor. I have done medical and office buildings that speced IG, and just pulled regular green #12 into EMT. The inspector said I can run one home IG run per 2 or 3 circuits. BX IG cable comes with your regular bare bonding conductor and IG solid green conductor.
 

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We have a couple places around here where you will get turned down if the IG isn't striped, but I think one of them actually has an amendment.
 

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NOPE, and did I say NOOOOOOOO.

Not when the AC distribution is properly installed.

And I have corrected problems at TV stations, Radio, recording studios, video recording studios, telecom centers, data centers, hospitals and a slew of others.
A few others have replied to my response, so I'll just grab the last one...

I respect that you have been able to correct problems at numerous locations. I can't deny that it's possible, but by utilizing an IG system from day one, there aren't any issues which need to be corrected.

It's crazy to me when a perfectly sound method of grounding and bonding is so adamantly put down. An isolated grounding system is part of a properly installed AC distribution system.

An isolated grounding system (star ground) isn't much different than standard grounding methods. The IEEE, NEC, and various government and military manual, instructions and handbooks highlight the methods and benefits of an isolated ground.

A few of those references include: NFPA 70, IEEE Green Book, IEEE Emerald Book, the Unified Facilities Criteria, and MIL-HDBK-411B. Those are just the ones off of the top of my head.
 

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evidence

There is no evidence that an isolated ground helps with any of that.
The IEEE tends to disagree. Numerous case studies are presented in the Green and Emerald books.
 
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