I know this probably has been discussed many times before but here it goes again. If you don't have copper water pipe how do you ground. Do you have to drive two ground rods? The reason I ask a friend of mine is working in a town where the plumber is using Pexs "plastic" and now the town is making them use copper pipe from the water meter to the water heater so the electrician has a place to ground. Why make the plumbers do the electrican work?

[This message has been edited by texassparky (edited 09-19-2006).]

Running a copper pipe from the water meter to the water heater does not provide a ground for the electric service. If the water service is non-metallic, one could use the rebar of the foundation for the Grounding Electrode (Mandatory in the '05 NEC) for new construction, or a made electrode consisting of one or two rods for other than new construction. The metal pipe installed in the interior of the building must be bonded per 250.104(A) but it is not the grounding electrode.

Let me ask this if you where to put a 200 amp service on a barn its all wood dirt floors and no plumbing you would only have a 8' ground rod with a #6 connected to it correct?. We bond water pipe so in case it becomes energizer there is no hazard. So why do we have to size coldwater ground according to the service size?

Has to do with the surface area contact of a ground rod versus a metal water pipe. I guess supposedly, most water pipes have more surface area contact to the ground. The larger wire increases safety. Are you megging out the ground rod?

When the water pipe ground was originally used you were essentially attached to every water pipe in town. The whole city was a ground grid. At that point the ground electrode could really clear faults so it made sense to size it to the service.
These days a bolted fault to the ground electrode alone would just be a worm chaser.

Ufer ground (if available).

(2) 8' Grounds if the Ufer's not available.

And a #4 copper jumper to anywhere on the copper water piping system (hot or cold). Preferrably do the grounding near the water meter as to making it easier for the AHJ to find (and see). Also, don't forget to jump out the hot & cold at the hot water heater.

[This message has been edited by ShockMe77 (edited 09-21-2006).]

Can someone tell me why it has to be at the water heater? I've had contractors tell me the inspector wants the cold and hot water pipes and the gas line all bonded together "at the water heater".

IMO this code isnt enforced often..... Technically if the water and gas service are plastic underground, and the cold hot and gas inside are metal you need to bond them all to an electrode or main panel.


It's that "may" thats debatable. And if you can get away with doing it at the water heater - hey why not.



[This message has been edited by e57 (edited 09-22-2006).]

Good question, George. I have to assume (I dislike using that word, alot), that the reason is because it's a common space that's easy to look for and to identify that it's been done. It's a matter of convienence in my opinion.

I think it's because the inspect is lazy or not smart enough to understand the issues of bonding and grounding.
It would be pretty rare for the H & C water piping systems not to be bonded together via a mixing valve in a bathroom or a faucet in at a laundry tub. As for the gas line it more tan likely will be bonded via the EGC of any appliance that has electricity run to it. I'm trying to think of a gas appliance that would not have electricity run to it and drawing a blank. Maybe a gas fired pool heater??

quote"I'm trying to think of a gas appliance that would not have electricity run to it and drawing a blank. Maybe a gas fired pool heater??"

For one, they make gas instahot heaters that do not have electrical controls at all. One type I have seen used recently you had to light a pilot lite in it. And one I came across about 2 years back had a device that sparked and struck a flame when the water flowed thru the pipes. It used the flow of the water . I used to see hot water heaters with constant pilot light years ago, but not lately. Most of those require 120 volt ignition.

macmikeman- In these aforementioned appliances were the piping for the gas and the piping for the water mechanically tied together on the appliance? If they weren't, I wonder what size the bonding jumper would be since the sizing is based on 250.104(B). Probably #14 AWG.

Edited for this added thought-

Plus we have the added issue of "may become energized" and I wonder how it will become energized with no electricity going to it. Now if we determine that it "may become energized" we are required to bond the gas line with an unknown size of conductor to the GEC, Grounding Electrode etc. etc.

[This message has been edited by George Little (edited 09-23-2006).]

For what it's worth I have been told by pundants that the ground rod would burn off before the #6 Cu in the event of a high faul current.

I've also been informed that the life of a ground rod is in some soil conditions is limited.

In my read of the article posted by e57, the water heater is a natural place for bonding. In this area interior copper is the usual plumbing, but the well is in PVC. As stated by others, the issue is bonding, not grounding. The water heater typically has dielectric unions and it's possible that all the faucets will be plastic. Another good place for a jumper IMO is the softner which usually has a plastic bypass. This bonds all the interior plumbing unless someone patches in pvc.

Dave

Even if the faucets are metal, the supply lines are usually plstic. I wouldn't count on a hot/cold bond there.
George, most (all?) gas pool heaters will still have an electrical interlock so they won't fire up unless the pump is running and they usually have a "fireman switch" that keeps the pump going a minute or so after the gas is off.

Greg I see your point. So in that case the EGC will possibly be adaquate for bonding the gase line.

My original point was that we have inspectors who ask that the H & C plus the gas be bonded together "AT" the water heater. The purpose of the bonding of the H & C water pipes at the water heater is to maintain the continuity of the water piping system through the dielectric unions on the water heater.
The purpose of bonding the gas line is to establish a path for current flow shoud the piping be energized. Clearly 250.104(B) tells us how to bond the gas line and bonding it to the water pipes is not one of the places that it list. Since the water pipes at the water heater are probably more than 5 feet from the entry of the water service they don't qualify as the water pipe electrode.

I always liked the language about using the EGC of the circuit likely to energicze the piping. That is usually accomplished in the design of the product. Trust but verify is my motto tho.
We did a bunch of those gas space heaters in state projects and I had one on the ground that they let me look over before the install. They had a bonding terminal for the EGC that was solidly connected via the internal metal parts to the pipe hub. Made up gas tight this is a good bonding path.

In terms of a non-electric water heater, we just installed one in a shop under construction. The shop wasn't going to be complete before the cold weather set in, so we installed the in-floor hydrothermal heat early, before the electric was finished and live (we also installed it early due to the heating being in the concrete floor). Thus, we used a constant-pilot water heater tank to heat the floor, and needed no electricity.

Trobb- So did you bond the gas line? If so why? Was it likely to become energized? How did you bond it? I don't mean to be sarcastic, I'm interested in knowing.

When ever I did a job with a pilot light only gas appliance in it I skipped bonding the gas pipe figuring it is not likely to become energized. Some local inspectors did not concur and I have had to go back and bond two times I can remember. "Is this a hill you want to die on?"

G. Little- As far as I know he (the main spark) did not bond it. However, as I mentioned there was no power when the WH was installed so he might plan to bond it later. I'll have to ask him his plans sometime. Sorry I can't be more help right now.

You gents would have a hard time in my neighborhood. In general the whole area here will inspect for this: (Mandatory and no debate) Cold-water <5'of interior, Hot water at the heater no less than #8, and depending on the town or existing service either gas at the water-heater, or new services from the second fitting of the gas main to the main panel or electrode in less than #8. Hot-tubs and Jaccuzis bonded local to unit in #8+. The thinking is that any pipe in the building "may" become energized by any branch or even the service. And has been that way for a long-time here. It's a check-list item for them...

Anyone else out there live in a jurisdiction that forbids (by the Poco) bonding of the gas line? I don't know the reasoning, but I know we never bond the gas line or meter. Can anyone explain this?

Tripp- If you wire the furnace you bond the gas line automatically. The mechanical code will not allow a nonmetalic gas line.