[jadrma]

I have a 100amp Service Panel which seems adequate for my small 1500 sq' house. I got a quote for a new 200amp panel installed for $2700 so think I'll wait until I expand the house. However, I am converting my plumbing to plastic supply lines and will not have metal to attach the ground to except for 30' away from the existing service panel where the only remaining metal cold water line comes in through the foundation wall to the main shutoff valve. Can I route an adequate-sized ground wire that far and attach it to the supply side of the main shutoff valve? What size grounding wire should it be and can it be bare?

Also, I intend to install grounding rods just outside the existing panel and ground to those as well. Will there even be a need to ground to the cold water line?

[stanfortyman]

The cold water ground is your main ground if you have metallic pipe coming into the house.
If you have a plastic pipe feeding the house, such as with a well, then the water pipe connection is just a bond for the piping system.

In your case you must have a grounding connection to the water pipe within 5' of where it enters the house. You must also jump (with an additional clamp) around the meter and any fittings (such as a plastic filter housing) that breaker the continuity of the metal piping.
You can use a #8cu wire for this. It can be bare also, this is typical.

[jadrma]

I appreciate your response and I think I understand. I need to ground to the waterpipe within 5' of where it enters the house. However, can the groundwire be 30' in length from the panel to the grounding clamp?

[stanfortyman]

Sure it can. You should see some of them we have to run. :eek:

[tkrussell]

If I may, I would like to confirm Stan's advice, the metal water line will be the main grounding electrode, and as you mention, the water line must be supplemented with at least one ground rod. Check local codes on this. At least one New England state require at least two rods for all services, for example.

What I like to do, when possible, is drive the ground rod close to the water line entrance in the basement. The #8 copper grounding electrode conductor from the panel will be clamped onto the water line, twice to jump out the water meter on both sides, and leave a continuous tail to attach to the ground rod nearby.

This gets the ground rod even deeper into the earth, and eliminates the exposed conductor and rod clamp from outdoors.

[jadrma]

I understand the beauty of installing the ground rod(s) near the waterline entrance to the basement but what if the waterline entrance is 30' (around the side of the house) from the Service Panel? I was going to install the two rods just outside the Service Panel and then run a separate 30' ground line around the interior of the basement and clamp it to the waterline coming into the house. Would this be okay?

[tkrussell]

Sure, why not? What is the issue with this 30 feet?

[JimfromSTL]

I just read this thread and have a follow up question... my house was built in 1979 and the grounding wire from service panel connects to my cold water pipe... but (a) is about midway in my basement and more than 5' from where the could water enters my basement... is the 5' rule something new or did I misinterpret something?

[ballengerb1]

Jim, I think they are talking about an outside ground rod must be driven 5' outisde the foundation and then connected with #8 wire to the water pipe. You are talking about inside your basement, right? That wire can be the length of the basement if you want or need.

[KISS]

No, rules change.

How much you have to fix depends on the extent of the removation.

For instance, in the house I live in, the service panel is about 2' from the water line. I would guess that there is 11' of copper pipe before the cold water pipe heads underground to emerge up at about 15' later. The cold water pipe has to follow about 35' of length to reach where the water actually enters the house. Copper pipe everywhere. No ground rod either. Fuses too, no breakers.

Polorized 2 prong, grounded outlet boxes everywhere unless upgraded to three prong. Most are indeed 3 prong. I upgraded 4 outlets last year. I even upgraded them to tamper proof.

[tkrussell]

Let me clarify a few things.

IF a home has a metal water pipe serving the home, it MUST be used as the primary grounding electrode, PROVIDING it has at least ten feet of metal buried water pipe outside the home.

The grounding electrode conductor can only connect to the water pipe NO FARTHER than five feet away from the entrance of the water pipe into the home.

This was clarified in the code a few cycles ago due to the increasing use of plastic pipe and or fittings that can get installed in a cold water piping system in the home. Any plastic fitting would break the continuity of the grounding if it was attached too far away from the entrance of the water pipe.


AND, WHEN a buried metal water pipe is utilized as the primary grounding electrode, IT MUST BE SUPPLEMENTED WITH AT LEAST ONE EIGHT FOOT GROUND ROD, as required by code.

What I have done in the past is grounding electrode conductor I run from the service to the water line, after I jump out the water meter as Stan mentioned, I leave a tail long enough to continue onto the ground rod, which I try to drive into earth right near the water line. Otherwise I leave it long enough to go outside to connect to the rod.

[KISS]

Is it true that the grounding conductor should be #6 for residential up to 200 A?

And

The wire from the service panel to the ground rod should be continuous?

It is true that the water companies were putting in plastic bodied meters at one time, so both sides of the meter need to be grounded.

Tk:
Glad you have been watching over us.

PS: I think that "What you should tell us piece that you asked me to write is working"

[stanfortyman]

Is it true that the grounding conductor should be #6 for residential up to 200 A?

The GEC to just a ground rod (or two) or pipe electrode never needs to be larger than #6cu. This is unless it is subject to real physical damage.
The reason we use #4 for a 200A water pipe is due to the size requirement in 250.104(A)(1).
250.66(A)
250.64(B)

The wire from the service panel to the ground rod should be continuous?

True for the GEC to the first rod or any other electrode. The jumper to a second rod does NOT need to be continuous, but is usually just as easy to keep it in one piece.
250.64(C)

It is true that the water companies were putting in plastic bodied meters at one time, so both sides of the meter need to be grounded.

From an NEC standpoint it is that and that a meter is removable.
The water bond must also be kept continuous by jumping around anything else plastic bodied like filters, etc..
250.68(B)

[tkrussell]

tk:
Glad you have been watching over us.

I have not been watching as much as you may think.

I went on a short vacation back in Jan, and when I got back I found I had to get busy to stay busy.

I only would look in every couple of weeks, and glance around if that.

Just had some time in the last few days to add my 2 cents, for whatever it's worth.