What are the bonding requirements for CSST gas piping?
Quick answer
All corrugated stainless steel tubing (CSST) gas piping must be directly bonded to the electrical service grounding system with a #6 AWG copper conductor or larger. The bond clamp goes on the CSST steel manifold or on a rigid pipe segment downstream of the gas meter — NOT on the CSST tubing itself.
This is required by NFPA 54 / IFGC 310.1 and by every major CSST manufacturer's instructions (Gastite, OmegaFlex/TracPipe, HOMEFLEX).
Why CSST is special
Unlike black iron, CSST has a thin stainless wall — about 0.010 inches at the corrugations. A nearby lightning strike can induce enough voltage on the gas piping to arc through that wall, igniting the gas. Several house fires in the 2000s traced back to indirect lightning strikes on unbonded CSST.
Bonding ties the gas piping to the same potential as the building's electrical ground, so when a surge hits, it dissipates harmlessly through the bonding wire instead of arcing through the pipe wall.
The exact requirements (NFPA 54 7.13)
- Bond conductor: #6 AWG copper minimum (some jurisdictions require #4)
- Bond location: as close as practical to the point of CSST installation, on the rigid steel side of the system
- Connection method: listed bond clamp rated for the conductor size
- Termination: to the electrical service grounding electrode system or grounding-electrode conductor
- Continuity: no painted or coated joints in the bond path
Manufacturer-specific updates (arc-resistant CSST)
Newer arc-resistant black-jacket CSST products (Gastite FlashShield+, TracPipe CounterStrike) have additional jackets that reduce — but do not eliminate — the bonding requirement. Always follow the manufacturer's current installation instructions in addition to the code.
What this means on the job
- Install CSST per manufacturer's instructions.
- Run a continuous #6 copper from the rigid steel pipe (downstream of the meter, upstream of the CSST manifold) to the electrical service ground.
- Use a listed bond clamp — no quick clips, no painted contact points.
- Document it on the rough-in inspection; inspectors will look for the bond before signing off.
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