No water pipe to ground to

[kwired]

May I ask you?

First I'd like to thank you all for sharing all of this with me. I started frequenting here a couple a months ago after just going out and wiring and letting the "tech" aspect of this fall by the wayside.

Let me ask you.............. What if this detached garage had no water, but it did have a gas pipe run to it?

From what I see the code says it must be bonded.......yet with the ceu I went to, it was mentioned that it is grounded thru the electric cord from the oven, or dryer, or thru a boiler, and the instructor said
in his opinion the gas pipe should not be grounded/bonded.........and if the inspector wanted it to be (which I guess he should cause it's in the good book), you should have him sign off on it.


Now.........this detached garage........lets say it has no water but it does have a gas line...............if there's nothing hooked up to it should it be bonded? If it's going to have an appliance that requires electricity,
I guess the same thought as above would apply and maybe you would not or should not bond it. I'm not sure of gas devices out there that wouldn't need electricity, but what if it used a thermopile, or you lit it by hand?



Again, just wondering, and thank you for getting my gray matter working.



By the way, what is your take on the conductors feeding the detached garage? Treated as part of a service for dwelling or not.


Thanks again!
Rich


Bonding to a gas line scares me to death with no water line present. Without the water line, seems the gas line might become the ground path for a fault current. I worked on a service with old splices overhead, tape long since weathered off & many bare spots. Wind blew a hot into the neutral. Popped a bit and a literal "ring of fire" traveled down the ground wire to the ground rod and set fire to the grass around it. If the gas line became the ground path, would such an arc not ignite the gas within?

You would need oxygen/gas mixture within the piping and enough heat to be above ignition temperature within the piping. Don't know for certain but is possible ignition temp would increase as pressure increases. Now if the arc made a hole in the pipe it could ignite escaping gas. Which is more of a problem with the thin walled CSST often used today inside buildings.

 

[ritelec]

250.52(B) does not permit using a gas pipe as a grounding electrode.

250.104(B) does require bonding metal piping systems including metallic gas piping.

OK, I'm lost with that.

So you don't use it as an electrode........but if you bond it.....does it not become part of the electrode system.

So it's the bonding/grounding thing also.

If the pipe was grounded via a plugin appliance, or boiler wiring......it would be grounded.
Yet to me, bonded would be back at the neutral/ground connection .which would make it an electrode........:huh:



By the way "HAPPY FRIDAY"!

 

[kwired]

OK, I'm lost with that.

So you don't use it as an electrode........but if you bond it.....does it not become part of the electrode system.

So it's the bonding/grounding thing also.

If the pipe was grounded via a plugin appliance, or boiler wiring......it would be grounded.
Yet to me, bonded would be back at the neutral/ground connection .which would make it an electrode........:huh:



By the way "HAPPY FRIDAY"!

Grounding and bonding is conusing sometimes. First thing to do that helps understand things is to learn definitions and proper use of them.

ART 100 definitions:
Bonded (Bonding). Connected to establish electrical continuity and conductivity.

That particular definition is pretty general and not limited to anything very specific.

Clear as mud when considering you have to bond the gas pipe but yet can't use it as an electrode isn't it?

One thing to remember is gas piping usually has dielectric unions before transitioning to underground - this prevents it from becoming an electrode, but even without the dielectric union you don't run an GEC to it like you do a metal water pipe. If a 15 amp circuit is all that is likely to energize it all you need to bond it with is a 15 amp conductor.

 

[ritelec]

Clear as mud when considering you have to bond the gas pipe but yet can't use it as an electrode isn't it?

One thing to remember is gas piping usually has dielectric unions before transitioning to underground - this prevents it from becoming an electrode, but even without the dielectric union you don't run an GEC to it like you do a metal water pipe. If a 15 amp circuit is all that is likely to energize it all you need to bond it with is a 15 amp conductor.

Yes....Clear as mud. ha ha ha

Thanks.

So back to this detached garage, with no water, but does have gas (with or without a dielectric union..lets say probably not),
and sitting right next to this pipe would be a 60 amp welder..would you run a 10 back to the panel from this gas pipe?

Edit: Rereading, you mentioned about a bond for the 15 amp circuit being a 15 amp.........wow......if you were to bond this pipe with a 60 amp welder sitting next to it....would you now use a #6 (or #8)?

If no welder, would you run anything back to the panel?

 

[kwired]

Yes....Clear as mud. ha ha ha

Thanks.

So back to this detached garage, with no water, but does have gas (with or without a dielectric union..lets say probably not),
and sitting right next to this pipe would be a 60 amp welder..would you run a 10 back to the panel from this gas pipe?

If no welder, would you run anything back to the panel?

Is the welder circuit likely to energize the piping? Probably not. Is the furnace connnected to gas pipe likely to energize the piping? Much more likely. The EGC for the circuit to the furnace is good enough to bond this gas pipe.

I would be more concerned with what the welder work leads could do to gas pipe than what the welder branch circuit may do, but this is not really an NEC issue IMO.

 

[ritelec]

Is the welder circuit likely to energize the piping? Probably not. Is the furnace connnected to gas pipe likely to energize the piping? Much more likely. The EGC for the circuit to the furnace is good enough to bond this gas pipe.

I would be more concerned with what the welder work leads could do to gas pipe than what the welder branch circuit may do, but this is not really an NEC issue IMO.

The gas pipe is there........it exists but nothing is hooked to it. Do you address the pipe?

 

[ritelec]

The gas pipe is there........it exists but nothing is hooked to it. Do you address the pipe?

Put a spackle bucket over it....... :thumbsup:

I know nothing........

 

[kwired]

The gas pipe is there........it exists but nothing is hooked to it. Do you address the pipe?

Most likely it is "not likely to become energized" therefore leave it alone. Otherwise bond to the EGC of the circuit likely to energize it.