ECN Forum Forums Code Related Discussion NEC & other Code issues bonding 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!