- CSST Bonding Definition: CSST (Corrugated Stainless-Steel Tubing) bonding is defined as connecting a conductor to the CSST gas pipe and grounding system to ensure safety
- Necessity of CSST Bonding: Proper bonding reduces the risk of fires or explosions caused by lightning strikes or power surges.
- Proper Bonding Technique: A bonding wire should connect to the rigid gas piping or directly to the CSST fitting, ensuring a secure and continuous path to the ground.
- Code Compliance: CSST bonding must comply with National Fuel Gas Code, International Fuel Gas Code, and Uniform Plumbing Code requirements.
- How to Bond CSST Gas Line Diagram: The diagram shows the correct way to bond CSST, ensuring the system is safely connected and grounded.
What is CSST Bonding?
CSST (corrugated stainless-steel tubing) bonding is a jumper from the metal gas piping to the building grounding-electrode system. That jumper gives a low-impedance path so nearby metal stays nearer the same potential in a lightning event. Yellow (standard) CSST makers require this extra bond. Arc-resistant (often black) CSST may follow a different listing. Use the tube’s instructions and the adopted code.
The bond must land on the same grounding-electrode system as the electrical service, not a private rod for the gas only. The intent is to limit voltage difference and the current that would otherwise jump as an arc from the thin CSST wall.
A correct bond lowers the chance of a puncture from a nearby strike. It does not make the piping a lightning rod and it does not remove all risk.
Why CSST Bonding is Necessary?
Unbonded yellow CSST has a known puncture history from nearby lightning. Utility “power surges” are a weaker match for this failure mode. Follow the listing; do not treat this page as a substitute for the code or the maker’s sheet.
A strike or induced surge can raise the piping relative to nearby metal. The thin corrugation then arcs and dumps energy into a small hole in the wall of the tube.
If that potential difference is large, an arc can pierce the CSST. A hole can leak fuel gas and start a fire. Bonding is meant to shrink that difference, not to carry lightning into the earth by itself.
The jumper aims at a nearer equipotential with other bonded metal. The stored photos below are examples of lightning-damaged CSST, not a complete failure catalogue.
CSST Bonding Diagram
Clamp the jumper to rigid pipe or to a CSST fitting (nut), never to the corrugation. The stored diagram is one layout. Place the clamp so the run to the grounding-electrode system is short.
The next photo is one field example. Match clamp, conductor size and landing point to the listing.
CSST Bonding Code
Adopted electrical and fuel-gas codes both apply, plus the CSST maker’s instructions. Where they differ, the stricter applicable rule and the listing win. This page is teaching copy, not a design spec.
NFPA 54 (National Fuel Gas Code), the International Fuel Gas Code and many plumbing codes require a direct bond for standard CSST. That work is electrical: a licensed electrician and the electrical inspector, under the adopted NEC or CEC. Local amendments differ.
Bonding Conductor
Route, protect and land the jumper per NEC (NFPA 70) or CSA C22.1, whichever is adopted. Do not land it on a driven rod that is isolated from the rest of the electrode system.
Makers and fuel-gas codes commonly require at least 6 AWG copper, or the listed aluminum equivalent, solid or stranded aluminum or copper conductor. Aluminum has extra NEC limits in damp or outdoor runs. The photo below is an example, not a size chart.
Many CSST maker sheets cap the jumper at 75 ft (22 860 mm) and say keep it as short as practical. Confirm that length in the current listing; do not assume every edition of NFPA 54 prints the same number.
Bonding Clamp
Never clamp onto the corrugated tubing. Use a listed clamp on rigid pipe or on a CSST fitting. “Any location” is too loose: pick a point that keeps the jumper short, often near where CSST begins.
Shorter is better for this lightning-equipotential job. The stored clamp photo is an example of hardware, not a permit to clamp the corrugation (the filename says CSST; the rule is still fitting or rigid pipe).
Use a clamp listed to UL 467 (or the local equivalent). It must bite clean metal on rigid pipe or the fitting, with paint or coating removed at the contact.
Grounding Electrode
The jumper must reach the building grounding-electrode system already used by the service. Common electrodes include:
- Rods
- Plates
- Structural Steel
NEC 250.50 requires those electrodes to be one system. Do not drive a separate rod “for the gas.” The stored figure is one electrode landing.
Grounding Electrode System
That system is the electrodes plus the grounding-electrode conductor. Gas-pipe bonding is not a DIY substitute for that work. Use a qualified electrician and the inspector who has jurisdiction.
