250.148 - 2008 Nec

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pete m.

pete m.

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Ohio
This question has most likely already been asked (I can't think of one on this site that hasn't been so far) but here it goes anyhow....

If you have a plastic box used as a junction box only and it containins two separate runs of NM cable, one 14-2 and one 12-2, and all of the conductors including the equipment grounding conductors are spliced within the junction box does 250.148 require that the 14awg and the 12awg equipment grounding conductors be joined to each other?

Thanks, Pete
 
"Where circuit conductors are spliced within a box, or terminated on equipment within or supported by a box, any equipment grounding conductor(s) associated with those circuit conductors shall be connected within the box or to the box..."

I guess I need some theory lessons here. Why would we need to connect equipment grounding conductors that are not asociated with their respective circuits together? What is it that we would gain from a safety standpoint?

To muddy the waters a bit more, assume that the two circuits are from different systems. Again, what do we gain from a safety standpoint by joining the EGC's from the separate circuits?

Pete
 
Your going to get all kinds of responces to this question. IMO yes. But now what if you have an IG circuit passing thru box?
 
Pete M,

What do we gain from a safety standpoint. This situation can only go two ways,

keep them seperate, or tie them all together. Keeping them seperate gives a

50/50 shot that they get crossed and go to the wrong panel. Tie them all

together and the EGC will go to the proper panel 100% of the time. jmo.
 
benaround said:
Pete M,

Keeping them seperate gives a

50/50 shot that they get crossed and go to the wrong panel. Tie them all

together and the EGC will go to the proper panel 100% of the time.
Click to expand...

If the branch circuits are from different systems (meaning two separately derived systems), why would fault current from one circuit want to return to the panel that is fed from the other system?

If both circuits are from the same system and the fault current goes to the "wrong panel" (the only reason it would or could as far as I know is that the "wrong" circuits impedance on the EGC was lesser than that of the faulting circuit) wouldn't the OCPD in the "right" panel still open? Especially if the fault current found a path of less impedance back to the source?

This is the crux of my confusion as to how tying all the EGC's together regardless of circuit or system creates a safer installation.

Perhaps I need more education:confused:

Pete
 
pete m. said:
If the branch circuits are from different systems (meaning two separately derived systems), why would fault current from one circuit want to return to the panel that is fed from the other system?
Click to expand...

It would not want to, it would want to return to the source, but if the EGC's

got flip flopped, I would say a less than safe condition was created, if all the

EGC's were tied together that could not happen.
 
Pete,

You're recycling questions form the Ohio IAEI site :rolleyes:

Click on this

No use wasting a perfectly good question when you can recycle it and keep it out of a landfill :grin:
 
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