Proper ground - water supply or rod?

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Tim K

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Location
Southeastern PA
I'm stuck in a debate with my electrician, perhaps you guys can settle it...

The situation:
The residential property we are renovating was built in 1992. The panel appears to have two "grounds". One wire from the ground/neutral bar is currently "grounded" to a cold water pipe which is about 10ft from the panel and about 30ft from where the service enters the building. In other words, well after the meter and not within 5ft of the outside. The second "ground" wire runs from the ground/neutral bar out through the wall, and attaches to a buried rod at the service entrance. (phone, cable, etc are also tied to this rod)

There is a jumper from the service side over the meter.
There is a bond between the gas piping and cold water line at the water heater.
There is not a bond anywhere I see between hot and cold water lines - I'm having him add one.

He says it is fine to leave it as is and that it is not necessary to spend the time and money to run 40ft of grounding wire from the panel to the service side of the meter because the panel is already grounded at the rod.
I say that current code requires the water line to be the ground, and that the grounding rod outside serves as a supplementary ground. I have no reason to believe the water supply line is anything other than metal all the way to the street, but I have no way of confirming it.

What say you?

As a follow-up, we are also putting in a manual transfer switch for a portable generator. The generator will need to be grounded to the building's ground....so that leaves the question of which is the "actual ground" and thus where to ground the generator - the water supply or the rod?

-Tim
 

iwire

Moderator
Staff member
Location
Massachusetts
The residential property we are renovating was built in 1992. The panel appears to have two "grounds". One wire from the ground/neutral bar is currently "grounded" to a cold water pipe which is about 10ft from the panel and about 30ft from where the service enters the building. In other words, well after the meter and not within 5ft of the outside. The second "ground" wire runs from the ground/neutral bar out through the wall, and attaches to a buried rod at the service entrance. (phone, cable, etc are also tied to this rod)

In 1992 that was likely a compliant installation.

First I will assume that there is at least 10' of metal underground water line that would quilfy as a grounding electrode. If you can see that it is all metal waterline between the water line entrance and the point the GEC is connected to the water line adding wire is in fact a total waste of time. Really, just toss money in the trash because you will gain nothing.

On the other hand your home may be supplied by a plastic underground waterline in that case it is not a grounding electrode. In this case the NEC only requires the inside metal waterline to be bonded to the panel. This connection can be made at any location on the waterline. If this is the case moving the connection is again a waste of money.

There is a jumper from the service side over the meter.


Good


There is a bond between the gas piping and cold water line at the water heater.

Not required by the NEC, not needed but will do no harm.

There is not a bond anywhere I see between hot and cold water lines - I'm having him add one.

What makes you think one is required?

All the NEC requires is that the hot and cold be bonded, it does not say how or where. Your shower valves and other spots that the hot and cold connect will take care of that bonding.


He says it is fine to leave it as is and that it is not necessary to spend the time and money to run 40ft of grounding wire from the panel to the service side of the meter because the panel is already grounded at the rod.
I say that current code requires the water line to be the ground, and that the grounding rod outside serves as a supplementary ground. I have no reason to believe the water supply line is anything other than metal all the way to the street, but I have no way of confirming it.

What say you?

I say let the electrician do their job and you do yours. :)

As a follow-up, we are also putting in a manual transfer switch for a portable generator. The generator will need to be grounded to the building's ground....so that leaves the question of which is the "actual ground" and thus where to ground the generator - the water supply or the rod?

The generator will be required to be connected to the buildings equipment grounding conductor. If the generator requires a grounding electrode depends on a couple of factors but if it does it can connect to any point on the existing grounding electrode system.
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
You may be required to meet current codes depending on your local jurisdiction and how much renovating you are doing.

I do not know that this was ever compliant. if there is a ground rod that is part of the GES, it is generally necessary to have two rods and not one. That requirement has been around a long time.

If the water line qualifies as a GE where it is hooked up is not compliant with current code.

you need to bond to the CEE is there is one if you are required to meet current code.
 
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Tim K

Member
Location
Southeastern PA
Thanks for the answers.

To address a few things...

I don't expect to be required to come up to code based on the level of renovations, but I may want to 'improve' a few things anyway.

One of the reasons I wanted to bond hot and cold is because I know at least some of the plumbing has PEX before the valves thus eliminating the hot/cold connection. I figure better safe than sorry (and adding a foot of copper won't hurt my bottom line).

As for letting my electrician do his job, well, I wouldn't be doing my job if I just let my subs tell me they are doing it right. Even the best ones make mistakes.:slaphead:

As for the water line, I am fairly certain it is all metal. It is metal coming into the house through the foundation. On the outside everything is original from when the development was built in the late eighties / early nineties and I don't think they were using plastic supply lines back then. Either way I am pretty confident that the grounding is covered considering both the water line and the rod. I was just curious which one would "technically" qualify as the ground and which would be "supplemental".
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
I was just curious which one would "technically" qualify as the ground and which would be "supplemental".

Simple. The one you connect to first is the ground, the second one, that you connect to with a jumper instead of a GEC, is the supplemental. :angel:
 
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