Bonding fuel gas piping systems

[Jerry Peck - Codeman]

I also put this under Fuel Gas.

There are basically five types of fuel gas piping systems used for houses:

- a) black iron pipe and other metallic pipe (such as copper where copper is allowed)

- b) CSST that is listed as being arc-resistant (these are typically the black CSST)

- c) CSST that is not listed as being arc-resistant (these are typically the yellow CSST)

- d) Combination of a) black iron pipe and b) arc-resistant black CSST

- e) Combination of c) non arc-resistant yellow CSST and ... anything else ... such as black iron pipe or arc-resistant black CSST (with "one or more" non arc-resistant yellow CSST in it).

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The NEC basically has the general requirements for bonding:
- 250.104 Bonding of Piping Systems and Exposed Structural Steel.
- - 240.104(A) Metal Water Piping.
- - 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
- - - - (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 conductor is of sufficient size
- - - The bonding conductor blah, blah, blah (does not matter for this discussion).


- - - ... oh, wait, there is one of those NEC Informational Notes below which says:
- - - - Informational Note No. 2: Additional information for gas piping systems can be found in Section 7.13 of NFPA 54 -2015, National Fuel Gas Code.

The above NEC stated, though, we use the IRC for houses, and the IRC contains its own Chapter 24 Fuel Gas Code, as well as the IFGC for buildings not under the IRC (note that IFGC section numbers are shown as (xxx.x) after the IRC section numbers).

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Yep ... that's it for "electrical" requirements for bonding of fuel gas piping.

But that is not "it" for requirements for bonding fuel gas piping.

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From the IRC:
- SECTION G2411 (310)
- - ELECTRICAL BONDING


- My comment Note A: The following three systems are essentially all bonded in the same manner: a); b); and d).
- - For "Pipe and tubing other than CSST": the gas piping is considered bonded when: "shall be considered to be bonded where it is connected to appliances that are connected to the equipment grounding conductor of the circuit supplying that appliance". I.e., gas piping OTHER THAN CSST is considered bonded when connected to a grounded appliance and its equipment grounding conductor.
- - - From the IRC: (bold and underling are mine)

- - - - G2411.1 (310.1) Pipe and tubing other than CSST.
- - - - - Each above-ground portion of a gas piping system other than corrugated stainless steel tubing (CSST) that is likely to become energized shall be electrically continuous and bonded to an effective ground-fault current path. Gas piping other than CSST shall be considered to be bonded where it is connected to appliances that are connected to the equipment grounding conductor of the circuit supplying that appliance.


- - For "Arc-resistant CSST": the gas piping is considered bonded when: "shall be considered to be bonded where it is connected to an appliance that is connected to the appliance grounding conductor of the circuit that supplies that appliance.". I.e., arc-resistant covered or coated CSST (typically black CSST) is considered bonded when connected to a grounded appliance and its equipment grounding conductor ... UNLESS ... "Where any CSST component of a piping system does not have an arc-resistant jacket or coating system", then the entire CSST piping system is treated the same as in G2411.2 (310.2) CSST for non arc-resistant yellow CSST.
- - - From the IRC: (bold and underling are mine)- - - - G2411.3 (310.3) Arc-resistant CSST.
- - - - - This section applies to corrugated stainless steel tubing (CSST) that is listed with an arc-resistant jacket or coating system in accordance with ANSI LC1/CSA 6.26. The CSST shall be electrically continuous and bonded to an effective ground fault current path. Where any CSST component of a piping system does not have an arc-resistant jacket or coating system, the bonding requirements of Section G2411.2 shall apply. Arc-resistant jacketed CSST shall be considered to be bonded where it is connected to an appliance that is connected to the appliance grounding conductor of the circuit that supplies that appliance.

This is the same as in G2411.1 (310.1) Pipe and tubing other than CSST ... put in one or more segments of yellow CSST and you treat the entire system the same as an entire yellow CSST system as stated in G2411.2 (310.2).

- My comment Note B: The following two systems have the exact same bonding requirements, with the bonding requirements being different than the other types: c) and e)
- - For "CSST" gas piping systems (yellow, non arc-resistant type), which includes black iron piping systems with "one or more segments of CSST": a) the bonding jumper shall be "bonded to the electrical service grounding electrode system or, where provided, the lightning protection grounding electrode system"; b) the bonding point of connection shall be "shall connect to a metallic pipe, pipe fitting or CSST fitting", and; c) the size of "The bonding jumper shall be not smaller than 6 AWG copper wire or equivalent".

- - - From the IRC: (underlining and bold are mine)

- - - - G2411.2 (310.2) CSST.
- - - - - This section applies to corrugated stainless steel tubing (CSST) that is not listed with an arc-resistant jacket or coating system in accordance with ANSI LC1/CSA 6.26. CSST gas piping systems and piping systems containing one or more segments of CSST shall be electrically continuous and bonded to the electrical service grounding electrode system or, where provided, the lightning protection grounding electrode system.
- - - - G2411.2.1 (310.2.1) Point of connection.
- - - - - The bonding jumper shall connect to a metallic pipe, pipe fitting or CSST fitting.
- - - - G2411.2.2 (310.2.2) Size and material of jumper.
- - - - - The bonding jumper shall be not smaller than 6 AWG copper wire or equivalent.

The key aspect to remember is that if there is "one or more" segments/components of non arc-resistant yellow CSST in the gas piping system, it is treated as though the entire gas piping system is non arc-resistant yellow CSST and must then be bonded in accordance with IRC G2411.1(310.2).

One must keep in mind that this is referring to CSST, not an appliance connector - having a yellow jacketed/colored appliance connector installed DOES NOT count as "CSST" (because it is not CSST).

A takeaway question:

If black iron gas piping is suitable for not requiring a #6 AWG bonding conductor, and if arc-resistant black covered or coated CSST is basically considered to be equivalent to black iron piping and does not require the #6 AWG bonding conductor ... if those gas piping systems are considered as equivalent to a #6 AWG bonding conductor, that thus allows segments of non arc-resistant yellow CSST to be considered as electrically continuous when part of a mixed segment gas piping system (black iron pipe and non arc-resistant yellow CSST or arc-resistant black CSST and non arc-resistant yellow CSST) such that the required #6 AWG bonding conductor may be attached to the mixed segment gas piping system at any accessible location?