Does CSST Gas Piping Need to Be Bonded? (IRC 2018)

Quick Answer

Yes. IRC 2018 Section G2411.1 requires CSST (corrugated stainless steel tubing) gas piping systems to be bonded to the building's grounding electrode system. The bonding wire connects the gas piping system to the same grounding point as the electrical panel, equalizing the electrical potential between the gas system and the structure and protecting against lightning-induced arc damage that can perforate CSST and cause gas leaks.

What G2411.1 Actually Requires

IRC 2018 Section G2411.1 requires that CSST gas piping be electrically continuous and bonded to the building grounding electrode system. The bonding connection must be made with a copper bonding conductor that is sized in accordance with the CSST manufacturer's installation instructions — typically 6 AWG solid copper, though some manufacturers now specify 10 AWG for certain pipe diameters. The conductor must run from the CSST system to the grounding electrode system, which is typically the ground rod, water service bonding jumper, or the grounding electrode conductor clamp at the main electrical panel.

The bonding jumper must be connected to the CSST system using a listed bonding clamp designed for CSST — standard plumbing pipe clamps or wire nuts are not acceptable. The connection point must be at a rigid fitting (such as a manifold, tee, or elbow fitting) where the clamp can be securely tightened without damaging the corrugated tubing. Some CSST manufacturers provide dedicated bonding attachment points on manifold fittings as part of their listed system.

G2411.1 requires that ALL CSST in the building be bonded — not just a single branch or the longest run. The entire gas system must be electrically continuous. If black iron pipe and CSST are used in the same system (a common configuration where black iron runs the main and CSST serves as branch lines), the metallic pipe connections ensure continuity, and a single bonding connection to the main body of the gas system is generally sufficient. However, if CSST branches are separated from the rest of the metal system by a non-conductive section (such as a dielectric union), each isolated section must have its own bonding connection.

The concern G2411.1 addresses is a documented failure mode: lightning striking a structure induces high-voltage transients that can arc through the corrugated wall of CSST, creating a pinhole gas leak at the arc point. Because CSST has thinner walls than rigid black iron pipe, it is more vulnerable to this type of damage. Bonding equalizes the potential and eliminates the voltage differential that drives the arc.

IRC 2018 Section G2411.1 requires that corrugated stainless steel tubing (CSST) gas piping systems be bonded to the electrical grounding system. The bonding conductor must be a minimum 6 AWG copper conductor connected at one end to the CSST system at a listed CSST bonding clamp, and at the other end to the electrical grounding electrode system including the grounding electrode conductor, the grounding electrode, the service neutral at the main panel, or the equipment grounding conductor in the panel. The bonding reduces the electrical potential difference between the CSST and the grounding system that can develop during a lightning strike on or near the building. Without bonding, a lightning-induced voltage difference can cause arcing through the thin CSST corrugation walls, creating pinhole leaks that allow gas to escape into the building over time. The bonding requirement applies to all CSST systems regardless of the lightning exposure level of the installation location.

Why This Rule Exists

Before CSST bonding requirements were added to the IRC, there were documented cases of CSST being perforated by lightning-induced arcing, resulting in gas leaks and fires. Testing by CSST manufacturers and by NFPA showed that properly bonded CSST eliminated this failure mode. The IRC added the bonding requirement in G2411.1 to make bonding mandatory nationwide rather than relying on manufacturers' installation instructions alone.

This requirement reflects the fundamental principle of the IRC that electrical and mechanical systems must be installed in a manner that protects occupants over the life of the building, not just at the moment of installation. Proper installation documented at inspection provides future owners and service technicians with confidence that the system was built to code, reducing liability and preventing disputes about pre-existing conditions.

What the Inspector Checks at Rough and Final

At rough inspection, the inspector checks that the CSST bonding conductor is run and connected to a listed bonding clamp at the gas system. At final inspection, the inspector verifies: bonding conductor is properly sized per the manufacturer's specifications, connection to the gas system uses a listed clamp at a rigid fitting, the conductor runs to the building's grounding electrode system with no breaks, the connection point at the grounding electrode is secure and accessible, and no section of CSST is isolated from the bonded portion of the system. The inspector may tug-test the clamp connection to verify secure attachment.

What Contractors Need to Know

Every CSST manufacturer has specific bonding requirements documented in the installation manual. Obtain and follow the current installation manual for the specific CSST brand being installed — requirements have evolved and differ by brand. Some manufacturers (such as CounterStrike/OmegaFlex CSST with a yellow jacket coating) have a reduced bonding requirement and may allow direct bonding at each appliance rather than at the system level — but this exception applies only to the specifically listed yellow-jacketed product. Standard CSST (black-jacketed) requires full system bonding per G2411.1.

Make the bonding clamp connection at the most accessible point in the gas system — typically at the first CSST manifold or fitting after the meter. Run the bonding conductor with the electrical system ground conductors if possible to keep it neat and protected. Label the bonding conductor at both ends: "GAS CSST BONDING CONDUCTOR — DO NOT REMOVE."

When installing CSST bonding, verify the bonding clamp is specifically listed for use with the CSST brand installed. TracPipe, Gastite, AutoSnap, and CounterStrike each have proprietary bonding clamp designs. Using a generic pipe clamp as a CSST bonding connection is a violation of both the manufacturer's installation instructions and the code requirement that the connection be made with listed fittings. The bonding clamp must make direct contact with the corrugated jacket of the CSST and not on a fitting. Install the bonding connection at a location that is accessible for inspection, typically at the CSST manifold near the main panel or at the mechanical room. Label the bonding conductor connection with a permanently marked tag reading CSST BONDING CONDUCTOR to assist inspectors and future electricians in identifying the bonding connection without having to trace the conductor from end to end.

What Homeowners Get Wrong

Many homeowners — and some contractors — are unaware that CSST bonding is required. Homes built or renovated in the early 2000s often have CSST installed without bonding because the requirement was added after CSST was already widely installed. An unbonded CSST system is a latent hazard that becomes acute only when a nearby lightning strike induces a voltage transient — an event the homeowner cannot predict. If you discover you have CSST in your home but no bonding conductor visible, have a licensed gas contractor add the bonding connection — this is a relatively low-cost retrofit.

State and Local Amendments

IRC 2018 states — TX, GA, VA, NC, SC, TN, AL, MS, KY, and MO — follow G2411.1 CSST bonding requirements. Texas, with its high lightning frequency and widespread CSST installation, has been particularly active in enforcing bonding requirements. Some jurisdictions require that existing CSST installations be retrofitted with bonding when a permit is pulled for any gas work. Confirm with your local AHJ whether retroactive bonding of existing CSST is required in your area.

IRC 2021 updated G2411.1 to provide more explicit bonding wire sizing guidance by manufacturer product type and clarified that yellow-jacketed (arc-resistant) CSST may have different bonding requirements per its specific listing. The core bonding mandate was unchanged.

When to Hire a Licensed Gas Contractor

Adding CSST bonding to an existing installation or installing CSST with bonding for new work requires a licensed gas fitter or electrician depending on jurisdiction — bonding involves both the gas system and the building's electrical grounding. Some jurisdictions require the work to be performed by an electrician because the grounding electrode system is under the electrical code. Others classify it as gas work. Confirm licensing requirements with your AHJ before beginning this work.

Common Violations Found at Inspection

• CSST installed with no bonding conductor — entire system unbonded
• Bonding wire connected to a water supply pipe rather than to the grounding electrode system
• Bonding clamp installed on corrugated section of CSST rather than at a rigid fitting — clamp can cut through the corrugated wall
• Bonding conductor undersized relative to the manufacturer's requirement for the system size
• Standard plumbing pipe clamp used as bonding attachment instead of a listed CSST bonding clamp
• Section of CSST isolated from the rest of the system by a non-conductive fitting — that section not separately bonded
• Bonding conductor not connected at the grounding electrode system — run to a receptacle ground rather than to the service entrance ground
• Yellow-jacketed CSST installed but standard bonding procedures applied — different listing requirements not followed