ECN Forum Forums Technical Discussion Electrical Theory and Applications water pipe grounding electrode

George,
U did'nt finish your story, what happened?

back on track,,,
prohibiting a water pipe GEC, and only bonding equates the same conductor. Isolating the metallic system & then bonding makes sense, but would require the plumbing trades interaction.

Would the overall GEC be compromised? Would options be pursued, i.e.-Ufers?

On what grounds was the last proposal shot down?
curious....

I've seen cases where the utility drop tension line/grounded conductor is snapped and there are still 120 volt circuits working properly in residences. I guarantee the neutral current was traveling thru the water pipe to the neighbor's and returning on their neutral.
Yes the plumbing system in each building would have to be isolated from the main system in order for this to work.
I think its a problem and have heard many stories from plumbers about faucets arcing. This also happens when the phone or cable company connects their ground on the load side of a dielectric plumbing fitting.
I am surprised we don't see more accidents. But electrical systems, even the oldest, are not that old, 70 or 80 years tops. The average is probably more around 50. As these systems get older and don't get replaced we may see an increase in injuries from these type of arrangements. If that happens the insurance companies will step in and get things changed.

Welcome to a reactionary society.

I got an addendum question to (DonsResqcapt19). Whenever we do multi-family dwelling we are allowed to daisy-chain all the Service panel together, for example, it there are three panels all the grounding electrode conductors are tied to the neutrals and finally at the end(last panel) goes to the water pipe and ground rods. If you put a clamp-on on those conductors not the last one but the up stream panels you are drawing a significant amount of current almost half of the neutral current. To me this means that the last panels neutral will be carrying a whole lot of extra current than it was designed for.

I can see quite a few problems with this.

I'll add more later this weekend if time allows.

Sound OK??

Scott SET.

Motor,
I don't think so. You have the grounded conductors in parallelwith the grounding electrode conductor. The current will divide in inverse proportion to the impedance of the different conductors. The current will be shared among the grounded conductors in the same manner. There shouldn't be enough difference in the impedances of the grounded conductors to have any of them overloaded.
Have you evr checked the current on all of the different conductors that are in parallel?
Don(resqcapt19)

Don (resqcapt19)
Maybe I missed on the description because I have checked the current on those grounds and the current is divided between the grounding conductor and neutral. From each panel except the one(first one that goes to the water-pipe and ground rod).
For example panel no.3 unbalance load comes back on its neutral to the neutral bar, it will see two pathes back to the transformer via the neutral going to the meter base from that panel and through panel no.2's neutral and through panel no.1's neutral.
Picture this three panels 1, 2, 3; panel no.3 has one copper conductor going to no.2 and then no.2 has a copper conductor going to no.1 then no. 1 goes to water pipe and ground, in all of these panels the neutrals are bonded, therefore the first two have low
Z pathes to the transformer, no.3 will see it through no.3 neutral and no.2 neutral the to no.1 neutral.
when I put a clamp-on on the no4 going to the water pipe it barely bobs the needle but upstream it is almost half of the return current.
I am not trying to be confusing here, but it almost seems like the neutrals on the other two panels should be up-sized.
I hope this explanation helps clear-up what i was saying

-Mark-

Don;
An addendum, to be technically correct these no.4's would be called a bonding jumper.
-Mark-

Mark,
First off, I don't think that the installation complies with 250.64(D), and I don't think it is a bonding jumper, but that doesn't change my answer. All of the neutrals have been connected in parallel by the grounding electrode conductor. The total neutral current will divide among the neutrals based on the impedance of the path from the neutral bus in the panel where the current originates back to the transformer. Why would the impedance of any of the paths be significantly different from the others? When you checked the current on the grounding electrode conductor, did you also check it on the neutral conductors?
Don(resqcapt19)

Don
There are 3 meters in a 3-meter base set-up and 3 separate service conductor cables and 3 service panels,.. for example, think of the panels as (3 2 1) no.3 goes to the ground rods, and as is the case for service panels the neutral is bonded to the grounding conductor, from no.3 to no.2 a jumper is run to its neutral buss, it too is bonded, from no.2 to no. 1 a jumper is run to its neutral buss and it to is bonded.
Yes the current will divide as per the ratio of the resistance of the neutral and the no.4 copper bonding jumper. in this case the no.4 copper copper will have less resistance than the no.4 grounded Neutral conductor of the service.
Now if you put a clamp-on on the jumper from 1 to 2 you will read a good deal of current and from 2 to 3 good current reading. but when you put the clamp on on the no.4 cndtr from no.3 to the ground rods the needle will barely move, why because the current at no. 3 is returning on panel no.3's neutral and the 25 ohms to ground is much larger than the resistance of panel no.3 aluminum neutral.
I hope I writing this clear enough I know what I am seeing but whether I am describing it correctly could well be another.
Yes on panels 1 and 2 its about evenly divided. All I am saying is that those first two panels are dividing their unbalanced current and sharing it with the bonding jumper and does that until it reaches the panel that is tied to the ground rods.

-Mark.