Natural gas piping

[dm9289]

Some back round aerial service SE cable disconnect in the basement of house in main lug panel gas pipe and water often enter house in same area.
250.104B talks about bonding metal pipe likely to be energized.

I have seen GEC leave panel box and in one piece (no splices) connect to incoming water main then go around water meter connection clamp again, then final end connect to metal gas main. Is this a correct practice?

Where some of my confusion comes in I'm doing 2017 NEC MH videos and the way I'm hearing it is gas pipe will only become energized by a device like a furnace that has power connected to it (120v for fan blower). So that circuit is adequate bonding and the extension to the gas pipe is not necessary. In my area the pipe often runs thru much of basements in close proximity to wiring so would that be likely to become energized?

Also in my small mind i get concerned with bonding to gas and possibly creating an arc that causes a problem or ignites gas within pipe


Please help confused

 

[infinity]

What type of gas pipe? Old style black pipe does not require additional bonding. It is bonded by the EGC of an electrical appliance that may energize it.

 

[dm9289]

What type of gas pipe? Old style black pipe does not require additional bonding. It is bonded by the EGC of an electrical appliance that may energize it.

Is there somewhere that states old black pipe does not need bonded that is the common type in my area

 

[infinity]

Look at 250.104(B).

 

[dm9289]

Look at 250.104(B).

yes i looked thru it a few times but i did not see black pipe does not need bonded

 

[curt swartz]

yes i looked thru it a few times but i did not see black pipe does not need bonded

It needs to be bonded but the EGC of the gas appliance is the bonding.

 

[dm9289]

It needs to be bonded but the EGC of the gas appliance is the bonding.

so i guess you are saying the concept is if the gas main 60ft away gets energized due rubbing thru some NM it will travel on the black pipe 60 ft to the appliance and fault via the appliances equipment grounding conductor

 

[retirede]

so i guess you are saying the concept is if the gas main 60ft away gets energized due rubbing thru some NM it will travel on the black pipe 60 ft to the appliance and fault via the appliances equipment grounding conductor

Exactly how does iron pipe “rub through” NM?

 

[dm9289]

Exactly how does iron pipe “rub through” NM?

I primarily work as an Industrial maintenance electrician and have seen some vibration problems with cables (installed incorrectly), but being as we are discussing residential, I imagine as you indicated rub thru is unlikely. I have seen decades ago in residential remodels piping being redone and pushing upward on NM but I guess this is very rare.

 

[electrofelon]

What type of gas pipe? Old style black pipe does not require additional bonding. It is bonded by the EGC of an electrical appliance that may energize it.

It needs to be bonded but the EGC of the gas appliance is the bonding.

There are two ways inspectors in my area will weasel around that. One is they claim that you don't necessarily know that the circuit feeding the appliance is the only circuit that is likely to energize the piping. Second, ( and IMO this is fair enough) they will claim that the EGC at the appliance does not necessarily Bond the gas piping and that you would have to investigate the manufacturer's instructions for the flex pipe connecting the gas pipe to the appliance to see if it is acceptable for bonding and if not provide a bonding jumper around it.

 

[infinity]

There are two ways inspectors in my area will weasel around that. One is they claim that you don't necessarily know that the circuit feeding the appliance is the only circuit that is likely to energize the piping. Second, ( and IMO this is fair enough) they will claim that the EGC at the appliance does not necessarily Bond the gas piping and that you would have to investigate the manufacturer's instructions for the flex pipe connecting the gas pipe to the appliance to see if it is acceptable for bonding and if not provide a bonding jumper around it.

And none of that is in the NEC so barring a local amendment they're making up a code requirement.

 

[electrofelon]

And none of that is in the NEC so barring a local amendment they're making up a code requirement.

Well in fairness they do not define why is "likely to energize". And the flex hose connector thing seems reasonable, I mean what if it was non-metallic or had a dielectric union? In other words the EGC serving the appliance might be acceptable as the bonding conductor, but does the ground screw or terminal in the wiring compartment necessarily bond to the gas pipe?

 

[NTesla76]

I don't know if I've come across a gas appliance connector that wasn't suitable for bonding. I'll have to look closer and see if one comes up. On another note, the gas utility around here requires a 6 AWG to the black iron before they will allow gas service.

 

[dm9289]

Well in fairness they do not define why is "likely to energize". And the flex hose connector thing seems reasonable, I mean what if it was non-metallic or had a dielectric union? In other words the EGC serving the appliance might be acceptable as the bonding conductor, but does the ground screw or terminal in the wiring compartment necessarily bond to the gas pipe?

Maybe its just me but it all seems as clear as Mudd. But the 2017NEC handbook had this comment top left other highlighting is for use as GEC

 

[infinity]

Well in fairness they do not define why is "likely to energize". And the flex hose connector thing seems reasonable, I mean what if it was non-metallic or had a dielectric union? In other words the EGC serving the appliance might be acceptable as the bonding conductor, but does the ground screw or terminal in the wiring compartment necessarily bond to the gas pipe?

If there is isolation between the gas appliance and the gas pipe then how can it become energized?

I agree that the words "likely to become energized" are silly. There isn't much of anything that is normally not energized that is likely to become energized.

 

[electrofelon]

I don't know if I've come across a gas appliance connector that wasn't suitable for bonding. I'll have to look closer and see if one comes up. On another note, the gas utility around here requires a 6 AWG to the black iron before they will allow gas service.

Yeah I don't know, I have never dug into the instructions of one. Washington State basically requires you have the instructions there printed for the inspector showing him that it is acceptable for bonding, or you bond with a number six back to the service.

 

[electrofelon]

If there is isolation between the gas appliance and the gas pipe then how can it become energized?

I agree, but again inspectors here Will claim all those other circuits that run over the gas line as it snakes through the building could energize the piping.

I know what the NEC says but really doesn't make a lot of logical sense. So if They are saying that the circuit feeding the appliance does the bonding, and if there is no circuit feeding the appliance or the gas line is electrically isolated from the appliance then it is not likely to become energized then no bonding would be required.....so why don't they just delete that whole section??? It's a bunch of words for nothing. There are already other sections requiring an EGC be run with the circuit supplying the appliance of course.