Why does CSST need to be bonded?

CSST (Corrugated Stainless Steel Tubing) is a flexible pipe used for indoor gas installations. Following several major incidents, the Quebec Construction Code requires it to be grounded (bonded):

Why: CSST has a thin wall that can be punctured by a direct or indirect lightning strike. The electrical arc passes through the gas pipe, creating a hole that causes a gas leak and potentially an explosion. Several fires in Quebec and Canada have been attributed to this phenomenon.

Requirements:

• A #6 AWG copper bonding conductor (Section 10-206 of the Code) must connect the CSST to the panel ground bar
• The conductor can be insulated or bare (bare is often preferred in plumbing)
• The path should be as direct as possible — no unnecessary loops
• The bonding connection must be installed downstream of the gas meter, between the meter and the first appliance

Cost: CSST bonding installation by a qualified plumber costs about $150 to $300. An annual inspection is recommended.