Extending a GEC

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
How may time have we run into "open neutrals" It happens.
If there a water pipe electrode from a common water system then the GEC may help with an open neutral. If there is just a ground rod or two then it probably won't do much to help the open neutral problem because it's relying on the dirt as a return path for the neutral current.
 

Fred B

Senior Member
Location
Upstate, NY
Occupation
Electrician
I've had open neutrals and bad neutral (not totally failed), and this would give significant current and voltage onto the GEC at the first panel that bonding is made. It would seem this gave some measure of safety that otherwise wouldn't be there absent a a GEC connection. I've also had where the GEC was not made and the skin of the mobile home became energized with no path back so no breakers tripped but had 120V on the metal skin.
 

ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min without traffic from wing
Occupation
Licensed Electrician
I've had open neutrals and bad neutral (not totally failed), and this would give significant current and voltage onto the GEC at the first panel that bonding is made. It would seem this gave some measure of safety that otherwise wouldn't be there absent a GEC connection.
If it was a water pipe electrode that may be. A ground rod wouldn't make a bit of difference, the contact resistance with the dirt is too high. There is a reason that GEC to a ground rod never has to be bigger than #6.
I've also had where the GEC was not made and the skin of the mobile home became energized with no path back so no breakers tripped but had 120V on the metal skin.
That would be the lack of an equipment ground.
 
Regarding a common water pipe that has a low impedance path back to the source: although that will certainly act as a neutral if the intended neutral fails, I don't see that being a valid consideration. First, that is simply not the purpose of a grounding electrode. Second, in practice, all I see that accomplishing is creating a significant current flow on the pipe which is a potential hazard, and at some point the pipe will be interrupted and then your stuff is going to fry anyway.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
How about this:

When the service neutral opens, each electrode is forced into having to attempt to carry neutral current, each to its ability to do so. Metallic water piping connected to neighboring water electrodes are the best, while rods are the worst.
 

JoeNorm

Senior Member
Location
WA
Isn't it quite dangerous to have current flowing on exposed piping? Wouldn't you rather know the neutral is bad so it can be fixed rather than not knowing and also having current on the GEC?
 
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