NEC 310.4 (B) requires all equipment grounds ran in separate raceway with parallel conductors to be a of the same cir mill. I had some larger conductor (both sizes were large enough to per 250.122). Would the world stop spinning and everyone fall off if one equipment ground is larger than the other in parallel runs? I know what the code says but what is the reason?
equipment ground in parallel conductors
- Thread starter wyboy
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- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I suppose if there were a ground fault then the shorter wire may try to carry more ground fault current than the longer one. Probably not ever a problem but let's see what others say. Of course, I don't condone doing it.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Since each EGC is required to be sized according to the OCPD ahead of the feeder I don't think that have one larger than required would matter much.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Sorry I read it as longer--oops--- not larger
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
When 310.4 states that conductors in parallel installations shall be of the same characteristics, it does not include EGCs in the list of conductors to which this requirement applies. So having two different size EGCs in two raceways of a parallel installation is not a code violation, provided each is of at least the minimum required size for the application.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Charlie. 310.4 does include the egc in 2008, however I still don't see it as an issue
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
You are right. I missed that. I wonder how they justified that change, as I don't see a technical or safety issue with it either.
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