ECN Forum Forums Code Related Discussion NEC & other Code issues Cold water ground

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?"