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I recently became aware of the need to bond a gas distribution containing yellow CSST flexible pipe. (TracPipe FGP SS4 750 5 PSI FUEL It has a yellow jacket)

When our propane system was converted to natural gas the contractor used a combination of existing iron pipe and yellow CSST pipe. The current system starts with 50 feet of CSST pipe at the meter connected to a short iron pipe manifold near the furnace. A second separate 20 foot section of CSST pipe runs from the manifold to a section of iron pipe serving the water heater. The manifold also feeds the furnace with iron pipe and the fire place with another section of CSST pipe.

The meter is on the opposite side of house from the electrical entrance and the electrical panel.

I see no attempt to bond/ground the gas piping.

It looks like there may be a dielectric union on the house side of the gas meter but I have not verified that the house is isolated electrically from the meter.

My questions are:

  • What is the proper way to bond such a mixture of CSST and iron pipe?

  • Does anything need to be done to insure that the three runs of CSST meeting at the iron manifold are electrically connected?

  • Can the system be bonded at the meter to a ground rod? Can the system be bonded to the electrical panel from the iron pipe serving the water heater?

I hope to find a knowledgeable contractor to do this work but I want to understand what needs to be done.

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    Can you get us info on who made the CSST in question? Commented Apr 10, 2021 at 1:57
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    TracPipe FGP SS4 750 5 PSI FUEL It has a yellow jacket
    – Mike D
    Commented Apr 10, 2021 at 15:19

1 Answer 1

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The furnace already has bonded the gas system...just not well enough for CSST purposes

In your current setup, the gas piping (both CSST and black iron) is bonded to the electrical system via the equipment grounding conductor of the furnace. This is typical practice for black-iron systems, but isn't good enough for CSST, which needs a much lower resistance path to the rest of the grounding and bonding system to keep excessive amounts of lightning energy from flowing on the CSST, creating arcs and pinholes as it goes.

In particular, you need to run a 6AWG copper wire from a grounding clamp on the black iron (preferably on the manifold, or on the black iron run to the furnace if that isn't possible) to some point on the grounding electrode conductor system that is within 75' of the bonding point. This is set out in IRC G2411.2.1 thru 2.3 (aka IFGC 310.2.1 thru 2.3):

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 not be smaller than 6AWG copper wire or equivalent.

G2411.2.3 (310.2.3)Bonding jumper length.

The length of the bonding jumper between the connection to a gas piping system and the connection to a grounding electrode system shall not exceed 75 feet (22 860mm). Any additional grounding electrodes installed to meet this requirement shall be bonded to the electrical service grounding electrode system, or where installed, the lightning protection grounding electrode system.

Parts-wise, you can use any ordinary pipe grounding clamp to attach the wire to the pipe, and a split-bolt or lay-in T-tap (Ilsco GTT-2-2 or equivalent) will work for attaching the bonding wire to the grounding electrode conductor.

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  • Thanks very much. A couple of follow up questions. 1) Is stranded insulated wire ok? 2) What color is commonly used? 3) Can the wire be cable tied to the CSST or should it be physically separated from the CSST?
    – Mike D
    Commented Apr 12, 2021 at 12:22
  • @MikeD -- 1) yes, insulated wire can be used, I suggested bare because it's a) conventional and b) a bit cheaper 2) if you are going with insulated wire, I'd suggest green, although there are no color-coding requirements in the NEC for bond wires 3) I'm not sure? I'd probably route it separately from the CSST since you want it to take a "straight shot" to the grounding electrode conductor, though Commented Apr 12, 2021 at 22:31

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