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I'm trying to interpret and apply the 2017 NEC bonding requirements from 250.104(B) to my existing home gas line. I've read this related question to determine I should use #6 AWG wire, but I'm unsure of how to exactly connect the wire to my gas pipe where it enters my home.

2017 NEC Bonding Requirement - 250.104(B)

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

(2) Service equipment enclosure

(3) Grounded conductor at the service

(4) Grounding electrode conductor, if of sufficient size

(5) One or more grounding electrodes used, if the grounding electrode conductor or bonding jumper to the grounding electrode is of sufficient size

The bonding conductor(s) or jumper(s) shall be sized in accordance with Table 250.122, and equipment grounding conductors shall be sized in accordance with Table 250.122 using the rating of the circuit that is likely to energize the piping system(s). The point of attachment of the bonding jumper(s) shall be accessible.

Question

What is an acceptable means of "bonding" the grounding wire to the gas pipe per code?

For example, code probably wouldn't approve the use of duct tape. Is some sort of clamp OK? If so, what kind and material? Or do I need to solder the wire to the pipe? Seems dangerous with a gas pipe, so guessing the answer is no, but let me know.

Edits based on comments

  1. 2017 NEC is enforced in my city. I've updated the code pasted above accordingly.
  2. My gas pipe is black steel.
  3. Updated wire size per Ed Beal's guidance.
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  • What is the gas line made of? What appliances are connected to it?
    – ThreePhaseEel
    Commented May 31, 2018 at 0:16
  • Also, what edition of the NEC is adopted in your jurisdiction?
    – ThreePhaseEel
    Commented May 31, 2018 at 0:17
  • @ThreePhaseEel, I've updated my questions with answers to your comments. Thanks.
    – Scott Lin
    Commented May 31, 2018 at 0:36

3 Answers 3

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There are several types of brass clamps depending on your AHJ. Some will allow acorn style clamps some require the style that has a separate screw for the wire to be secured and the brass clamp on the pipe. Only # 6 is required # 4 is required for concrete encased electrodes but everything else in a residential install # 6 would meet code ( it is ok to use #4 if the clamp is listed for that size). I am talking about copper wire here.

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typical pipe bonding clamp

This is what I usually see used in the field for bonding pipes of any kind. You can get them at Menards, Home Depot, Lowes, etc. They are pretty easy to install and self explanatory. Note the built-in bonding lug for the conductor.

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Refer to 2017 NEC Article 250.53 (B)(1) - Gas piping systems should not be used as a grounding electrode. Once a hundred years ago we were trained never to connect grounds to gas piping. The reason in the event of a ground fault electrical energy is transferred through the grounding system which could create a spark or heat that might ignite the gas.

Due to the fact that most underground piping systems are no longer metal, some AHJ do want to see the gas piping used as part of a grounding electrode system. Personally I like my old training and it still isn't allowed by the NEC.

Edit: See comments below. Due to confusion I have attached the following coment taken from the NEC Handbook Article 250.140 (B) enter image description here

Hope this helps.

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  • RME read the question. The OP wants to comply with the code requirement to bond the gas pipe not use it as a ground electrode. This has been a requirement for years as the OP listed.
    – Ed Beal
    Commented May 31, 2018 at 15:12
  • @EdBeal - You are correct, However the title question is asking "How to connect grounding wire to gas pipe for 2017 NEC 250.104(B)" and then proceeds to reference NEC 250.104 (B). Given that we are answering questions to DIYers, I wonder if they could be confused with the differences of grounding, grounded, bonded, etc. I have edited my post for clarification.
    – Retired Master Electrician
    Commented May 31, 2018 at 16:51
  • The key difference electrically between bonding the gas pipes vs using them as a grounding electrode is that all-important isolating fitting. I asked a question about that on the electricians reddit and about 50 idiots replied with the wrong answer. Three people knew the right one.
    – Robert M.
    Commented Dec 12, 2023 at 23:08

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