Bonding at water heater

[infinity]

As far as what the rest of ya'll are debating, recall that the code requires bonding gas and water piping systems. Doing so at the water heater (where all the typical pipes are usually present) is seen by most inspectors I've dealt with as an easy way to do this, although it's not the only way. If you want to argue that gas is bonded at appliances, well, I'd say the onus would be on you to prove it in any given case.

What code section requires a bonding jumper to a gas pipe?

 

[jaggedben]

What code section requires a bonding jumper to a gas pipe?

250.104(B) in the 2020 NEC.

I see the section numbering changed in 2020 but the language did not.

 

[infinity]

250.104(B) in the 2020 NEC.

I see the section numbering changed in 2020 but the language did not.

An external bonding jumper to the gas piping system is not required by that section.

250.104(B) Other Metal Piping.
If 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 any of the following:
(1) Equipment grounding conductor for the circuit that is likely to energize the piping system

 

[jaggedben]

An external bonding jumper to the gas piping system is not required by that section.

I didn't realize the specificity of your question but I think it is moot within the larger point I made. From an inspection point of view, unless your going to go around and inspect the connections to appliances and open up appliances for the inspector to show that there is internal bonding, then you'd better show the inspector an external bonding jumper. Or for another example, how is an inspector supposed to sign off on new construction for occupancy if the appliances are not installed? Also, the paragraph following what you quoted says that attachment points for bonding jumpers shall be accessible. So frankly, I think you are just reading it wishfully. For practical purposes, the code requires an external bonding jumper.

 

[infinity]

For practical purposes, the code requires an external bonding jumper.

The NEC wording in post #23 is pretty explicit that it is not required. Also if there are no appliances installed then there is nothing that will make it likely to become energized.

 

[LarryFine]

Can't the presumption of compliant and inspected installations be made, that any gas appliance with an electric supply will be fed with a properly-connected EGC?

 

[infinity]

Can't the presumption of compliant and inspected installations be made, that any gas appliance with an electric supply will be fed with a properly-connected EGC?

The way that 250.104(B)(1) is written it makes that assumption.

 

[Dennis Alwon]

I agree that the assumption is there. However what happens in a home that only has a gas stove that plugs in a 120v receptacle and an electric range is installed later. I will bet no one will forsee that the gas piping is no longer bonded. The question is Does it need to be bonded if it is not likely to be energized.

We also can't seem to have an agreement as to what likely to be energized means. I have heard some cmp members say if there is a circuit feeding the gas appliance then it is likely to be energized while others feel if nm cable is run across the gas line then it is also likely to be energized.. Personally I'll go with the former.

 

[infinity]

We also can't seem to have an agreement as to what likely to be energized means. I have heard some cmp members say if there is a circuit feeding the gas appliance then it is likely to be energized while others feel if nm cable is run across the gas line then it is also likely to be energized.. Personally I'll go with the former.

There is nothing in 250.104(B) to support the bold part.

 

[Dennis Alwon]

There is nothing in 250.104(B) to support the bold part.

I agree but there is nothing to explain what is meant by the term "likely to be energized"

 

[infinity]

I agree but there is nothing to explain what is meant by the term "likely to be energized"

True and is anything referenced in the NEC really "likely" to become energized? Look at the definition of likely. The answer is....

 

[Dell3c]

250.104(B) Explanation from 2020 NEC Handbook. Where the phrase "likely to become energized" is used in the NEC, it means that failure of electrical insulation on a conductor can cause normal non-current-carrying metal parts to become energized. Where mechanical and electrical connections are within equipment, a failure in a electrical insulation can result in the connected piping system(s) becoming energized. For example, an insulation failure in a electrical circuit of a gas range could energize the metal gas piping.

The use of an additional bonding jumper is not necessary to comply to comply w/250.104(B), because the equipment grounding connection to non-current-carrying metal parts of the appliance also provides a bonding connection to the metal piping attached to the appliance. Section 250.104(B) requires the gas piping system to be bonded. It does not make the gas piping part of the grounding electrode system. Therefore, this requirement does not conflict w/ 250.52(B), which prohibits the use of metal underground gas piping systems as grounding electrode. To prevent the underground gas piping from inadvertently becoming a grounding electrode, gas utilities usually provide an isolating fitting. Gas utility companies also often provide cathodic protection of their underground piping system.

 

[Dell3c]

I'm a GC in the SF Bay Area. We recently completed a kitchen remodel and on the final inspection the building inspector is making us run a bonding wire from the gas line to the hot and cold water lines at the water heater and bring to a nearby subpanel. These are located in the garage near each so its not hard to do. My electrician says it isn't necessary or correct, he says just run it from the cold water to the gas line. My dilemma is I've got to deal with this inspector on other jobs, so I don't really want to go to the mat on this issue so I'll do what he asks. My question is, is this a hazard or is it just a a pointless, yet harmless exercise?

Noticing your on west coast also. I've having let my California License go (for the second time now) effective April 2d this month. So might not be bad idea to check if "Cali" having amendment to 250.104(B) because greater State of Washington has..

WAC 296-46-250.104(B) Bonding -Other Metal Piping
(9) For flexible metal gas piping installed in new or extended from a existing ridged metal piping system, either:
(a) Provide a copy of the manufacturers bonding instructions to the inspector @ the time of inspection and follow those instructions: or
(b) The bond conductor for the gas system must:
(i) Be a minimum 6 AWG copper; and
(ii) Terminate at:
(A) An accessible location at the gas meter end of the piping system on either a solid iron gas piping fitting using a listed grounding connector;
and
(B) Either the Service equipment enclosure, service grounding electrode conductor or electrode, or neutral conductor bus in the service enclosure.

 

[jim dungar]

Likely does not mean possible.
It is possible you will win a lottery, but it is not likely.

For applying the NEC, and other NFPA documents, I would say 'likely' could occur due to a single failure, while 'possibly' would require multiple simultaneous failures.

 

[K8MHZ]

What would be likely to energize it?

Somewhere I have a picture I took that is of old NM cable in contact with a metal gas pipe. It wore through and the hot conductor came in contact with the gas pipe and arcs occurred whenever there was a strong vibration in the house, like truck traffic makes. It was an easy fix, but still.....yikes!!!

 

[jaggedben]

The NEC wording in post #23 is pretty explicit that it is not required. Also if there are no appliances installed then there is nothing that will make it likely to become energized.

I'm dumbfounded by this statement. Are we reading the same text? Everything you say is the dictionary definition of implicit, not explicit. And it is entirely the judgment call of the AHJ.

 

[jaggedben]

Somewhere I have a picture I took that is of old NM cable in contact with a metal gas pipe. It wore through and the hot conductor came in contact with the gas pipe and arcs occurred whenever there was a strong vibration in the house, like truck traffic makes. It was an easy fix, but still.....yikes!!!

Right.

The AHJ I worked in that was most stringent about gas pipe bonding was the same one where perhaps the majority of the housing stock featured gas pipes running across the joists above unfinished garages in close proximity to live knob and tube wiring, which every now and then someone had hung their laundry from with metal hangers. They weren't going to get any arguments from me on this point.

As I said above, it's entirely the judgment call of the AHJ.

 

[jaggedben]

The way that 250.104(B)(1) is written it makes that assumption.

250.104(B) says absolutely nothing about appliances. I'm ignorant of gas appliance standards. Do listed gas appliances have internal bonding jumpers that meet the requirements of 250.104(B)? One would expect an informational note if the CMP intended this to be a solid interpretation.

 

[Dell3c]

Section 250.104(B) requires the gas piping system to be bonded. It does not make the gas piping part of the grounding electrode system. Therefore, this requirement does not conflict w/ 250.52(B), which prohibits the use of metal underground gas piping systems as grounding electrode. To prevent the underground gas piping from inadvertently becoming a grounding electrode, gas utilities usually provide an isolating fitting. Gas utility companies also often provide cathodic protection of their underground piping system.

I have highlighted & separated this from above #32 posting.. Understanding it's not quote NFPA70, but only explanation of the NFPA70 (Handbook)

 

[Doc13067]

Everybody has ignored the part of the OP where it talked about bonding pipes to a nearby subpanel. That part is wrong. Just bond the pipes to each other, not to the subpanel.

As far as what the rest of ya'll are debating, recall that the code requires bonding gas and water piping systems. Doing so at the water heater (where all the typical pipes are usually present) is seen by most inspectors I've dealt with as an easy way to do this, although it's not the only way. If you want to argue that gas is bonded at appliances, well, I'd say the onus would be on you to prove it in any given case.

Agreed. That’s what I usually do. However, look what I just found. Curt Swartz nailed it.

“Typically, the use of an additional bonding jumper is not necessary to comply with 250.104(B), because the equipment grounding connection to the non-current-carrying metal parts of the appliance also provides a bonding connection to the metal piping attached to the appliance.”

Excerpt From
NFPA 70®, National Electrical Code® (NEC®) Handbook, 2014 Edition
National Fire Protection Association (NFPA)

‎NFPA 70®, National Electrical Code® (NEC®) Handbook, 2014 Edition

‎Professional & Technical · 2013

books.apple.com

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