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Thread: Bonding Gas line

  1. #1

    Cool Bonding Gas line

    Hello all,
    I had the inspection today on the service upgrade from 100 to 200 amps (the infamous panel that had to be moved from above the dryer to the other side of the wall). The inspector passed the installation, but was not satisfied with the EGC in the 12 gauge cable feeding the furnace as providing sufficient bonding for the gas pipes in the home. He said just jump to the gas pipe from a point on a cold water pipe. So I ran a continuous piece of #4 copper from clamp to clamp around the water meter, then to a clamp on the gas pipe that feeds the water heater 4 inches away. This is an older house, where 100% of the water pipes are copper, and 100% of the gas pipes are iron; no non-metallic pipes mixed in anywhere. There is #4 copper wire running from the neutral buss of the main panel to a clamp on the water pipe where it enters the home. I just wanted to see if my method described above of bonding the gas pipes was acceptable, or do they also need to be bonded right where they enter the house?

  2. #2
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    If you are just bonding the gas pipe, that bonding wire can connect to any location on the gas pipe. I don't believe there are any restrictions in the number of joints in that bonding wire, but I'm not so sure the code allows a copper or iron pipe to be a conductor. However, I think most would allow it if you have multiple pipe bonding clamps side-by-side on a segment of pipe.

    Your continuous piece of #4 is fine. Hopefully, its starting point in on a clamp real close to where the ground electrode conductor clamp attached to the water pipe.
    Mark
    Kent, WA

  3. #3
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    Hopefully, its starting point in on a clamp real close to where the ground electrode conductor clamp attached to the water pipe.
    Not required, but excellent idea!
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    So where are the legal places a bonding wire may originate from?
    Mark
    Kent, WA

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    Quote Originally Posted by suemarkp View Post
    So where are the legal places a bonding wire may originate from?
    From the secondary side of the metal gas pipe (Indoors) to anywhere on a continuous metal cold water pipe. It can be sized based on the appliance (being served by gas) with largest EGC.
    Learning brings success. While you are waiting, I'm getting better!

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    My concern is how do you bond a gas line to the cold water supply with #4 copper and not inadvertently make it a grounding electrode if the water pipe is being used as one? It would seem you would need a dielectric union between where you bond the pipe and earth.
    Last edited by Roger; December 8th, 2009 at 06:26 PM.

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    Quote Originally Posted by Ohm1 View Post
    From the secondary side of the metal gas pipe (Indoors) to anywhere on a continuous metal cold water pipe. It can be sized based on the appliance (being served by gas) with largest EGC.
    I'm not so sure I agree. 250.104(B) says: "bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or to the one or more grounding electrodes used.". I think there is also an implict allowance of connecting to some other bonding wire which eventually goes back to one of these locations, since splicing is allowed.

    So the question becomes, if the water pipe is an electrode, how much of it is actually the electrode? Baring any other guidance, I'd say any continuous metal pipe within 5' of where the pipe enters the building is your ground electrode (as is the buried pipe outside if you could see it to verify it is continuous).

    I do think having to run a #4 was excessive, since the code says whatever is likely to energize the pipe. Unless there are some large wires crossing over it, I'd say the equipment ground to the gas appliance is sufficient.

    The interior metal gas pipe is going to be bonded if any electric device is connected to that piping. Hopefully, a dielectric union was installed outside so it does not turn the buried gas pipe into an electrode. Around here, much outside gas piping is plastic now anyway.
    Mark
    Kent, WA

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    The interior metal gas pipe is going to be bonded if any electric device is connected to that piping. Hopefully, a dielectric union was installed outside so it does not turn the buried gas pipe into an electrode. Around here, much outside gas piping is plastic now anyway.

    Looks like we had the same thoughts Mark....


    It is becoming more common that inspectors are wanting gas lines bonded to the grounding electrode system or back to the service equipment. I'm not sure but I think there is a big controversy going on about this...with the NFPA and NEC and the gas companies. Some local jurisdictions amending the requirement of the egc serving as the required bond if the gas line serves a electrically operated piece of equipment or applaince. They want a #6. I'' try to find documentation of an example and post later.

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    Ok I wasn't quite correct this controversy with bonding gas pipes is over gas lines that are csst......here is a long article but the best one I've seen.

    Sorry about the pdf I hate the things

    http://www.toolbase.org/pdf/techinv/...ngconcerns.pdf

    Here is a technical bulletin from a state with its summary ruling on metal gas pipe bonding. Sorry again it's another freakin pdf.

    http://www.nh.gov/safety/divisions/f...pipebnding.pdf

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    Quote Originally Posted by suemarkp View Post
    I'm not so sure I agree. 250.104(B) says: "bonded to the service equipment enclosure, the grounded conductor at the service, the grounding electrode conductor where of sufficient size, or to the one or more grounding electrodes used.". I think there is also an implict allowance of connecting to some other bonding wire which eventually goes back to one of these locations, since splicing is allowed.

    So the question becomes, if the water pipe is an electrode, how much of it is actually the electrode? Baring any other guidance, I'd say any continuous metal pipe within 5' of where the pipe enters the building is your ground electrode (as is the buried pipe outside if you could see it to verify it is continuous).

    I do think having to run a #4 was excessive, since the code says whatever is likely to energize the pipe. Unless there are some large wires crossing over it, I'd say the equipment ground to the gas appliance is sufficient.

    The interior metal gas pipe is going to be bonded if any electric device is connected to that piping. Hopefully, a dielectric union was installed outside so it does not turn the buried gas pipe into an electrode. Around here, much outside gas piping is plastic now anyway.
    Suemark,

    It doesn't say we are limited to a portion of the electrode selected. I can understand your point (safety concern), but code does not say that only a portion of the selected electrode is the only part you can use. Yet it does say: to one or more of the grounding electrodes used. Anywhere on a continuos metal cold water pipe will qualify--if indeed it is properly grounded.



    Your thoughts?
    Last edited by Ohm1; December 9th, 2009 at 12:17 AM.
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