Kai Mallari's Notes'

CSST-Bonding-Is-Regulated-Electrical-Work-Not-Gas-Work (Home Systems)

4 min read

CSST Bonding Is Regulated Electrical Work, Not Gas Work

idea decision-rule

Claim: bonding corrugated stainless steel tubing (CSST) gas piping to the electrical grounding system is classified as regulated electrical work under the BC Electrical Code (Rule 10-700), not gas work — it requires a licensed electrician in addition to a licensed gas fitter. Many homes with CSST installed before the mid-2000s are unbonded, which creates a lightning-strike perforation risk.

Mechanism

CSST is a flexible yellow-jacketed stainless steel tubing used for residential gas piping since the 1990s. Its thin corrugated walls make it vulnerable to electrical arc perforation: if a lightning strike induces a high-voltage transient on the building’s grounding system, unbonded CSST can arc-through, creating a hole in the gas line inside the wall cavity. This has caused fires.

The bonding requirement:

  • CSA B149.1 (the BC gas installation code) requires CSST to be bonded unless it carries an arc-resistant jacket certification.1
  • The bonding conductor must be a minimum 6 AWG copper wire attached to the CSST system downstream of the gas meter and connected to the building’s electrical grounding system.1
  • BC Electrical Code Rule 10-700 governs equipotential bonding of non-electrical systems including gas piping.1

The trade split:

  • A licensed gas fitter installs and modifies the CSST piping system (permitted gas work).
  • A licensed electrician installs the bonding conductor connecting the CSST to the electrical ground (permitted electrical work).
  • Both are required if a CSST system is being installed new or if an existing unbonded CSST installation is being brought to code.

How to identify unbonded CSST:

  • Look for yellow flexible tubing in visible pipe runs (basement, utility room, behind appliances).
  • Look for a bare copper wire (6 AWG minimum) attached with a clamp to the CSST and running to a grounding electrode or the electrical panel’s ground bar.
  • If you see CSST with no bonding wire attached anywhere visible, the system may be unbonded — ask a gas fitter or electrician to assess.

Why it matters even in a strata:

  • CSST is commonly used for in-suite and riser runs in multi-unit buildings.
  • If the CSST riser passes through common property (which it typically does), bonding involves both the gas fitter for any piping scope and the electrician for the conductor — and strata coordination if the bonding attachment point is on common property.

Scope

Does NOT cover:

Idea Compass

North: Where this comes from

  • gas-lines (Home Systems) — the gas component this rule governs
  • Technical Safety BC Information Bulletin on CSST bonding — the BC regulatory source
  • CSA B149.1 — the installation code that mandates bonding

East: Tensions / failure

  • The assumption that bonding is “part of the gas fitter’s job” — it is not; it requires a separate licensed electrician
  • Pre-mid-2000s CSST installations that predate stricter enforcement — many are unbonded

South: Where this leads

West: What’s similar

  • Gas-Lines-Owner-Scope-Is-Recognition-Not-Repair (Home Systems) — the broader owner-scope principle; CSST bonding is an example of a “gas” issue that also has an electrical trade dimension
  • Seismic strapping of water heaters — another cross-trade requirement (plumber installs the tank; strapping may involve a separate contractor)

Sources

Footnotes

  1. Technical Safety BC — Information Bulletin: Electrical bonding requirements for gas piping or tubing systems; CSST must be bonded per manufacturer instructions and CSA B149.1 unless arc-resistant jacket certified; bonding is regulated electrical work under BC Electrical Code Rule 10-700; minimum 6 AWG copper conductor — https://www.technicalsafetybc.ca/regulatory-resources/regulatory-notices/information-bulletin-electrical-bonding-requirements-gas-piping-or-tubing-systems ↩ ↩2 ↩3

Graph View

Backlinks