Will an IG receptacle serve it's purpose if it's terminated at a sub panel where the grounded conductors and the EG conductors are not seperated? Seems that if it was taken all the way back to the main panel you would have the same scenario with the neutral and E grounds bonded there. Is the intent of the IG to be that there is nothing else on that grounding conductor that would cause "interference". Thanks.
IG termination
- Thread starter nizak
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lakee911
Senior Member
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- Columbus, OH
I thought that an IG receptacle was to be used on a system with an IG. My understanding is that the metal portion of the yoke device that attaches to the box is isolated from the grounding receptacle hole.
If you used it on a typical (non-IG) system, and had a metal box that was bonded, then the yoke would be bonded to the box and the grounding receptacle hole would be bonded by means of a conductor which would go back to the panel and bond to whatever bonded the box and connect to the neutral.
If you used it on a typical (non-IG) system, and had a metal box that was bonded, then the yoke would be bonded to the box and the grounding receptacle hole would be bonded by means of a conductor which would go back to the panel and bond to whatever bonded the box and connect to the neutral.
I see them spec'ed many ways. Some want IG back to the immediate panel that feeds the outlet, some want it back to the service.
Way back when, some were directed to their own ground rod (a Code violation)
The "importance" seems to have diminished over the years.
Way back when, some were directed to their own ground rod (a Code violation)
The "importance" seems to have diminished over the years.
The days of IGR are for the most part antiquated as communications (I/O) circuits today are not unbalanced ground referenced mediums. NEC has never or will every specify where the separation of EGC and IG is to occur. It can be all the way back at the service entrance Neutral-Ground bond point which is preferred by designers (or at Isolation Transformer), but can happen anywhere down stream the installer wishes unless otherwise specified by contract. In a Nut Shell it is a design issue, not a code safety issue.
In the case of a wood framed structure employing NM and plastic boxes every branch circuit is IGR. Only way to improve which is questionable. is to use a dedicated branch circuit like you would on a laundry circuit or MW oven.
In the case of a wood framed structure employing NM and plastic boxes every branch circuit is IGR. Only way to improve which is questionable. is to use a dedicated branch circuit like you would on a laundry circuit or MW oven.
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LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
There's no correct answer to this, because the sub-panel's neutral and EGC's should be separate.
Nonetheless, that's where the IG should be landed: where the MBJ is. In your case, the sub-panel is probably just as effective.
Basically, to assure that the chassis of each piece of equipment so isolated will never rise above zero volts.
Moreso, the IG assures that they never have a difference between them. Modern equipment is not as sensitive to such issues.
- Location
- Illinois
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- retired electrician
The code rules permit the isolated grounding conductor to be run back to the point where the main or system bonding jumper is installed, but do not require that it be run back to that point. As long as the "U" ground of the receptacle is connected to an EGC there is no code violation. It may not be what the specs intended and will not provide the benefit that an isolated ground connection run back to the bonding jumper is said to provide, but it will be safe and not a violation.
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