# "likely to become energized"



## peach (Jan 4, 2011)

We have a little discussion going on regarding gas piping (not CSST).  I believe IAEI is of the position that gas appliances, with an electrical connection, attached to a hard gas line, is per-se bonded by virtue of the EGC.

Which I agree with, but in the name of keeping the peace (or peach), would like other input.

I think back in "the day" where electricity traveled out and back in two wires (with no ground), the pipe could have easily been energized.. not so much now..

What say you, oh wise ones?


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## TimNY (Jan 4, 2011)

Not an electric guy.. and I don't have the NEC here.. but I do believe the bonding jumper has to be sized in accordance with a Table.

If they are using the frame of the appliance as a bonding jumper, how can you determine it complies with the Table.

Moreover, gas appliances usually have a small (at the most, 14ga) cord-and-plug attachment.  I don't know that the grounding conductor would meet the requirements of the Table (easy enough to look up), not to mention if you unplug the appliance, the gas pipe is no longer bonded.


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## Jobsaver (Jan 4, 2011)

I believe the determination of "likely to become energized" is determined by the conductivity of the gas piping, not the type of electrical system present, (grounded or not).

Good question though. I have wondered myself, "Why is a bonding jumper required in a grounded system?".  Good observations Tim.


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## Bryan Holland (Jan 4, 2011)

I have never been a fan of the phrase, "likely to" with respect to any code section.  In fact here is a proposal I write back in 2007 to change the 2008 NEC.  See the part about removing the phrase, "likely to".



> 1-105 Log #384 NEC-P01 Final Action: Reject(110.26(A))
> 
> Submitter: Bryan P. Holland
> 
> ...


Anyway, bonding is a great practice when in doubt.  You can't "overbond" and electrical premise wiring system.  The code recognizes that non-electrical conductive parts may unintentionaly come in contact with an energized part, conductor, or equipment of the electrical system.  In order protect from that hazard, an effective fault path must be created to ensure proper operation of the overcurrent device of the imposing circuit.  In some cases, the bond is created by the connection of the electrical system to an appliance or equipment also connected to the gas piping.  In this case, the circuit EGC serves as the effective fault path for the circuit, the appliance / equipment, and the gas piping.

There is not too much more to it than that.


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## chris kennedy (Jan 4, 2011)

Bryan Holland said:
			
		

> In this case, the circuit EGC serves as the effective fault path for the circuit, the appliance / equipment, and the gas piping.  There is not too much more to it than that.


Agreed and here is substantiation.



> 250.104(B) Other Metal Piping. Where installed in or attached to a building or structure, a metal piping system(s), including gas piping, that is likely to become energized shall be bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or the one or more grounding electrodes used. The bonding jumper(s) shall be sized in accordance with 250.122, using the rating of the circuit that is likely to energize the piping system(s). The equipment grounding conductor for the circuit that is likely to energize the piping shall be permitted to serve as the bonding means. The points of attachment of the bonding jumper(s) shall be accessible.


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## peach (Jan 5, 2011)

Thanks all... confirming my thinking.


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## Jobsaver (Jan 5, 2011)

Assuming a metal gas pipe installation in a home supplying only a gas log and gas water heater with no equipment connected to both gas piping and the electrical system. Separate bonding jumper required?


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## north star (Jan 5, 2011)

** * * **

Jobsaver,

Yes, a separate bonding jumper is required. See Section G2411.1 in the 2006 IRC.

If no equipment is installed, a separate bonding jumper is still required......The

gas piping itself can still "become energized".......Lightning would be a source to

energize the gas piping system in a residence.

** * * **


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## Jobsaver (Jan 5, 2011)

Okay, take the same installation, except the home is outfitted to accomodate a gas, or, an electric range. Back to TimNY's reference to the fact that if the range becomes unplugged, the gas line is no longer bonded. Or, in this case, if the gas range is replaced with an electric range.

The other argument I have against using 250.104 as substantiation, (see Chris' post above), is that we cannot be certain that the circuit(s) to which gas appliance(s) are connected have large enough grounding conducters to serve as a bonding jumper, except to those particular appliance circuit(s)? Larger circuits, for example, a sub-panel feed, in the same structure is "likely" to energize the metallic piping.

This is more of a question than a statement, having the highest regard for both Bryan's and Chris's knowledge of the NEC.


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## north star (Jan 5, 2011)

*$ $ $ $*

Jobsaver,

It seems as though we have uncovered another error in the codes

regarding the bonding of the gas piping systems......As Bryan stated,

you can never "over bond" a premise wiring system......Language

certainly needs to be added to the IRC and the NEC to address

this loophole.

I agree with the statement "when in doubt, add another bonding

conductor"!........Us code officials need some language to substantiate

this requirement though, ...other than "because we said so".

*$ $ $ $*


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