can water meter be supplimental ground?

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sparky17

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This is probably a stupid question, but , hey I can ask them too. I am wondering if in a service upgrade there is any reason that the water meter for the house (the current main Grounding conductor and electrode) can't be changed to the supplimental ground thus leaving the conductor sizing the same, and create another alternate viable grounding electrode ie: ground rods as the main grounding electrode conductor and up size this conductor to accommodate the new larger service ampacity.

Basically, is there anything saying the watermeter must be the main ground if it exists? This is a situation where the dwelling is a slab on grasde and no easy way to get to the water meter from the service (opposite corners of the dwelling and everything is finished.
 
The only stupid question is the one unasked - give or take. Welcome to the forum. :D

There is no such thing as a primary and secondary ground. All electrodes are (more or less ;) ) created equal in the eyes of the NEC.

250.50 requires us to use all electrodes.

250.53(D)(2) requires us to supplement a water pipe electrode (if one is present) with another electrode.

If you are upgrading the service and the GEC to the water pipe is too small, you are obligated to install the correct size GEC, in my opinion. Hopefully you worked that hardship into the bid. :)
 
I had an inspector in San Fransico tell me "two ground rods or prove how many ohms to ground on the water service".
I don't know if that answers your question or not but it bugged me at the time.:cool:
 
Yes I agree with your articles quoted. I'm just a little bit fuzzy on since both a water pipe and a ground rod are both grounding electrodes, can the water pipe be the supplemental ground and remain a #6 (which it currently is) while the upgraded #4 (200Amp service from 100A currently) goes to the ground rods?

And thank you for the warm welcoming.
 
georgestolz said:
The only stupid question is the one unasked - give or take. Welcome to the forum. :D

There is no such thing as a primary and secondary ground. All electrodes are (more or less ;) ) created equal in the eyes of the NEC.

250.50 requires us to use all electrodes.

250.53(D)(2) requires us to supplement a water pipe electrode (if one is present) with another electrode.

If you are upgrading the service and the GEC to the water pipe is too small, you are obligated to install the correct size GEC, in my opinion. Hopefully you worked that hardship into the bid. :)
Click to expand...



Since both a ground rod and a water pipe more than 10' in ground are both recognized as grounding electrodes, can the water pipe be a supplimental ground and 1 or 2 ground rods or 3 if we made a counterpoise(whatever), be the grounding electrode and be sized accordingly?

PS: thanks for the warm welcome
 
No - all electrodes are required to be connected by full size GEC's according to 250.66.

250.66(A, B & C) make allowances for certain electrodes - but the water pipe isn't among them. The ground rod is. This is the opposite of what you're shooting for, but it's a fact.

(Break your mental chain of 'primary/secondary' thinking - think of a water pipe as a novice swimmer that needs a buddy. The concept solely applies to the fact that the water pipe might be repaired with plastic someday, and leave the service without a connection to earth.

The water pipe may need a buddy, but it still stands on level footing with all the other types of electrodes.)
 
Thanks for your help.

I was hoping my brainstorming on a way out of making the customer upsize that wire brought out a loophole but as I suspected would be the case. My original sentimate was correct, and It must be changed.

Thanks again.
 
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