floater4444
Member
right on! thanks you guysbuckofdurham said:
EGC of subpanel
- Thread starter floater4444
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JohnJ0906
Senior Member
- Location
- Baltimore, MD
buckofdurham said:
The grounding electrode and GEC has nothing to do with clearing a ground fault.
Read 250.4(A)(1 through 5)
JohnJ0906
Senior Member
- Location
- Baltimore, MD
In a ground fault, the electricity is seeking to return to source. EGC, to neutral/ground bond at the main service entrance (or SDS) to neutral winding of the XFMR.
floater4444
Member
thanks you guys!
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Okay, what you have is a 200 amp panel (main service) feeding a sub panel. The sub panel must have 4 wires being fed to it and as John said separate the neutrals from the grounds. The main GEC must be run from the water line to the main service unspliced. If there is more than 10 feet of metal water line buried outdoors than you need to be within 5 feet of where the service enters the building.
Buck Parrish
Senior Member
- Location
- NC & IN
JohnJ0906 said:
In 250.4(A) 5
That tells you "it shall not be considered an effective ground fault current carry path"
I've done service upgrades where the water line ground was better then the utilities ground.
JohnJ0906
Senior Member
- Location
- Baltimore, MD
buckofdurham said:
How do you mean this?
The water line had less resistance than the POCO neutral?
Buck Parrish
Senior Member
- Location
- NC & IN
JohnJ0906 said:
I was doing a service change. Hooking the lines above the weather head to my service. I always do the neutral first.
One time the neutral was arcing until I fastened it good. The hot's we're not hooked up yet.
I was thinking that the nighbors houses with loads on them were actually feeding back through my grounded conductor because I had such a good ground.
What's your thoughts ?
JohnJ0906
Senior Member
- Location
- Baltimore, MD
buckofdurham said:
You very well might be correct.
You had a better neutral connection than they did, not ground.
Also, if there is municipal metallic water, some of the neighbor's neutral current will flow through your neutral, via the GECs and water pipe, under normal conditions. (And some of your's through theirs)
I think the EGC/GEC can't share only because a GEC is to be unspliced. How do you get it to the pipe unspliced without violating a rule?
If the water pipe is just being bonded and is not a ground electrode, what the OP wants to do may be legal. But he'd have to verify that the water pipe outside is non-metallic. If the pipe is just being bonded, I know of no issues for number of splices, wire routing/grouping/sharing, etc that would prevent this. It does have to be large enough the whole length though (and #4 cu would be right).
If the water pipe is just being bonded and is not a ground electrode, what the OP wants to do may be legal. But he'd have to verify that the water pipe outside is non-metallic. If the pipe is just being bonded, I know of no issues for number of splices, wire routing/grouping/sharing, etc that would prevent this. It does have to be large enough the whole length though (and #4 cu would be right).
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Smart $ said:
I believe you know the answer to that question but as mentioned it would be a difficult install. The op didn't appear to be asking that question.
Smart $ said:
How about if I tap off of the GEC to ground a (previously) un-grounded receptacle?
At that point, the EGC nd GEC are one and the same back to the panel....no?:smile:
I know that this is a different situation than the OP's problem, but... just for argument's sake.
steve
- Location
- Illinois
- Occupation
- retired electrician
The current flow was not because you had a better ground...it was because the metal underground water pipe is in parallel with the utility grounded conductor. In areas with a common metal underground water piping system, it is not uncommon to find 20% or more of the grounded conductor current flowing on the water pipe, however it has nothing to do with the path to earth (ground), it only has to do with the path back to the utility transformer XO terminal.buckofdurham said:
Not really. See my response to suemarkp...Dennis Alwon said:
His query is a lot like referencing a dictionary for how to spell a word for which the spelling is uncertain...!!!Dennis Alwon said:
Reading "between the lines", I say he's asking what is the easiest, cost-effective way to fix this problem?
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