We have to bond the hot, cold water and the gas line.

If its a 200amp service do I need to use #4 copper or can I just use #6?

Where in the code is this? Thanks

First off you really do not have to make any special effort to bond the gas line, that will be done by the EGC of the equipment connected to the gas line.

As far as the sizes take a look at Table 250.66

Trick, I think you are confusing "bonding" with "grounding."

This is also an area that is usually modified by your local codes, so you will want to check thing out at city hall, as well.

The wire that goes to your ground rod....the "grounding electrode conductor"....is specified by the NEC to need be no larger than #6, without regard to the size of the service. Many places have raised this to a minimum of #4 solid, and further require it be in pipe for extra protection.

Metal parts of the house that are likely to become energised are required to be "bonded" to the system. Such thing include the water line...but the gas service again is an area that local codes differ about. In any event, the NEC specifies a #10 bonding jumper, but many places specify at least a #8 wire be used.

You are no longer allowed to use the water service as a "ground;" you need that ground rod. You are, howerver, required to "bond" the water line.

Reno



I have no idea what you mean with either of those statements.

Well we ground the water line, but in addition..

We have to have a jumper the connects the cold to the hot and then to the gas line.

We ussually do this at the hot water heater. Thats bonding the gas line isn't it?

I would look at 250.104(b). Now as to what circuit rating to use, not as sure. for a 200 amp it says #6, but is that what would energize it?

Reno, could you elaborate on the water pipe grounding. Is that something in the 2005 NEC?

[This message has been edited by trekkie76 (edited 12-21-2005).]

Water Line Service
Grounding Electroide Systems (250.52) Sized per 250.66 (#4) If theres 10 ft. or Metal underground. If not its then its Bonding (See 250.104(A.1))Still sized by 250.66.

Gas piping 250.104B (Other metal Piping)
#6 copper . Unless pipe is grounded by an equipment grounding conductor of a circuit thats using the Gas . The equipment grounding conductor is then an effect bond.

Where I am in what has been refered to as the soveriegn city, of the soveriegn state of SF, CA. Water is required as an electrode and/or bond depending on how you look at it, and if a UFER is involved. Water with no UFER, would be supplimented with rods. With a Ufer, which would be full sized, water would be bonded anyway, in the proccess making it an electrode....

Hot to cold at the water heater...

Gas bond, at the second fitting past the meter - required! They'll even let you use the GEC so long as it is not between the electrode and panel.

Perhaps I should have said you're not allowed to use the water line as your ONLY ground....250.53(D) ays the pipe shall comply with (1) and (2)...and (2) says the pipe shall be supplimented.
We often forget that there are type of non-conductive pipe that pre-date plastic. Many cities still have wood water mains...and, more recently, WWII started the use of "orangeburg," a pipe made of asphalt-impregnated cardboard.

As far as the bond wire needing to be !0 or larger, I stand corrected....the NEC calls for it to be at least #8. Formerly, this was a local ammendment- it appears that the NEC has caught up! 250.104 is what I am referring to.

To be clear we are required to use a metal water line as an electrode as long as there is 10' of it in direct contact with the earth. It does not matter what is beyond that 10'. An 8' rod is an electrode so it only follows that 10' of metal water line in the ground is an electrode. It will not matter if that 10' of metal line is supplied by non-conductive mains.

In the big picture it may be better if you water line was not electrically continuous with your neighbors.

Yes we must supplement it with one or sometimes two additional electrodes. My guess is that is required as many times people disconnect the GEC from the water line and do not put it back.

I will have to look but I do not believe there is a minimum size bonding conductor for a gas line.

Bob-The sizing of the bonding conductor for the gas line is talked about in 250.104(B) and it refers to 250.122. Minimum size in this code section is #14 AWG cu or #12 AWG al. So I'm saying that's the minimum.

Call it grounding or bonding but there in my part of the NE it would take a LOT of effort to make a better electrode than the 50 or so feet of 1" copper waterline buried below the frost line running to the metal waterline in the street. Can't ignore that.

As for gas piping bonded to the equipment grounding conductor of the branch circuit supplying the equipment, how do you interpret that? Is there a BONDING JUMPER needed between the branch circuit conductor and the pipe? Or do you assume there is a connection in an appliance...sight unseen? Is is part of the appliance listing to assure a bond between the two?

George I am glad you brought this up, I was hoping someone would.


I do not think it is that easy.

part of 250.104(B)

If it is a cord and plug connected stove it may have a 16 or 18 AWG cord. That cord would also be the bonding jumper.

jes

part of 250.104(B)

I take this to mean that the gas pipe will be bonded by the appliances EGC.

I have yet to see a gas appliance that the gas connection was electrically isolated from the appliances enclosure.

IMO the thought of this section is that the gas line can not become energized if the appliances connected to it are properly grounded.




[This message has been edited by iwire (edited 12-24-2005).]

I don't see any reason to bond the gas piping under the 2005 code. (Note: CMP 5 does not agree with my statements on this subject.)
from the 2002 code:
from the 2005 code:
Any conductive object "may become energized", but many conductive objects are not "likely to become energized". In my opinion it is not likely that the gas piping system will become energized and therefore does not require bonding. Yes, it may become energized, but it is not likely. I think that CMP 5 made a mistake in changing the wording. I don't see this section as being enforceable with the 2005 wording. (I'm sure your AHJ will not agree, so you will have to provide the bond)
Don

I agree Don, the code panel has not made it easy for us when they have subjective rules in the book. since I'm looking at it from the Inspector side, I might lean towards bonding the gas line "just in case" no, not really. I know inspectors who want the I-beam in a residential basement bonded because their are NM cables laying on top of it. I think they are over doing it for sure. I am very comfortable with the bonding offered with the equipment grounding conductor of the branch circuit to the appliance. Even Bob's example of the #18 gauge conductor in the appliance cord. There are tons of NM cable branch circuits out there with reduced EGCs. Hey, it's very common for the EGC to be smaller than the grounded or ungrounded conductors. With a gas fired appliance using solenoids it's possible to energize the gas line and this bonding is necessary. There are very few gas fired appliances that don't use electricity.

It is not possible to energize the gas line if the appliance is properly grounded in the first place.

I agree with Bob. The only way the gas piping is "likely to become energized" is if it is in intimate contact with an electrical device or equipment. If it is in contact with it, it is already bonded by metallic continuity with a bonded object.

Ryan & Bob My response- Bingo, hence the bonding/grounding.

This is in Michigan for residential and we always have to bond the gas line.

So is it safe to say a #6 is more than enough to bond the gas line on a 200amp home?

This just came into effect for us about a yr ago, and on a few ocassions I have seen a tag out at the gas meter that says ' Do not bond to electrical system' .. go figure...

As iWire has pointed out...

part of 250.104(B)


The equipment grounding conductor for the circuit that may energize the piping shall be permitted to serve as the bonding means.

In other words, the grounding (bonding conductor) used in the branch circuit thats feeding the furnace/ boiler is adequate of bonding the gas pipe. No, you do not need to run a seperate #6 cu wire from the panel to the furnace/ boiler. The gas pipe "feed" is not permitted to be used as part of the grouding electrode system.

Good luck!