Ever had a job fail an inspection because of a bonding issue? You know the frustration. It’s one of those things that feels minor until it isn’t.
Gas meter bonding in the UK isn’t just a box to tick on a compliance sheet; it’s a safety essential. Yet plenty of installations still get it wrong, usually because someone thought “close enough” was good enough.
This article goes into what the rules actually say, why they exist, and which mistakes land jobs in the “failed” pile more often than most would admit.
What Gas Meter Bonding Actually Means?
Gas meter bonding is about one simple thing: preventing electrical shock or fire risk in the event of a fault.
The gas pipework in a property is metallic, so if there’s a fault in the electrical system, it can become live.
The bond creates an intentional, low resistance path between that pipework and the main electrical earth, equalising the voltage and keeping you safe.
It’s a small connection that does a big job. But you’d be surprised how many people still think it’s optional.
It’s not. Under UK regulations, bonding is required anywhere metallic gas pipework enters a building and connects to the gas installation.
The Current Rules (And Where They Come From)
These requirements come from the IET Wiring Regulations (BS 7671) and the Gas Safety (Installation and Use) Regulations. The short version:
- The main protective bonding must connect the incoming metallic gas pipe to the main earthing terminal.
- The bonding conductor should be a minimum of 10mm² copper (for most domestic installations).
- The connection point must be within 600mm of the meter outlet or before any branch in the pipework.
- The clamp must be accessible, secure, and attached to clean, unpainted metal.
You don’t need to be a spark to understand why these details matter. A loose clamp, a bit of paint, or an awkward routing can easily compromise the bond.
Why Does It Matter So Much?
Gas and electricity don’t mix well, everyone knows that. But the bonding rules aren’t just for show.
They exist because, in a fault condition, an unbonded pipe can carry a dangerous potential difference between the electrical system and earth.
Touch a gas appliance and a live metal surface at the same time, and you could complete that circuit.
Bonding evens the playing field. It ensures that if there’s a fault, everything metal in the installation rises to the same potential, making shock less likely. It’s not glamorous, but it’s lifesaving.
The Confusion Around “Supplementary” Vs. “Main” Bonding
This is where many people trip up. Main bonding connects services (gas, water) to the electrical earth.
Supplementary bonding connects different metal parts within a specific area, like a bathroom, to ensure local equipotential.
The mistake? Some assume supplementary bonding around a boiler or meter makes main bonding unnecessary. It doesn’t. If you skip the main bond near the meter, you’ve already failed inspection.
When Bonding Is Required, And When It Isn’t
As a rule, any metallic gas pipework entering a property must be bonded. But there are edge cases. For example:
- Plastic incoming pipes don’t need bonding (unless they transition to metal before the meter).
- Meter boxes outside still need bonding if the metallic pipework continues inside.
- If the gas system is completely isolated from the electrical installation (rare, but possible), bonding may not apply.
- Most domestic setups fall under the “yes, bond it” category. But those nuances are worth knowing, especially for inspectors looking at mixed-material systems.
Most Common Bonding Mistakes (And How to Avoid Them)
Inspections fail all the time over small oversights. The rules haven’t changed much, but the way they’re enforced has become sharper. Here’s where most people slip up:
1. Bonding On The Wrong Side Of The Meter
The bond should be made on the consumer side, after the meter outlet, but before any branches. Clamping to the inlet side or before the regulator is incorrect and will fail inspection.
2. Bond Installed Too Far From The Meter
The regulation calls for a bond within 600mm of the meter outlet. Anything beyond that and it’s considered non-compliant. It’s a simple measurement, but easy to miss when space is tight.
3. Paint, Corrosion, Or Dirt Under The Clamp
A dirty or painted surface means poor conductivity. Always clean down to bare metal before clamping. That shiny finish isn’t just for looks, it’s for performance.
4. Inaccessible Bonding Points
If an inspector can’t see or reach the clamp, it’s not compliant. Tucking it behind a boxed-in area or plasterboard might look tidy, but it won’t pass.
5. Undersized Bonding Cable
In most homes, 10mm² copper is the minimum. Anything smaller, say, a 6mm² from an old install, should be upgraded. Inspectors spot it instantly.
6. Forgotten Bonds During Upgrades
Replaced a meter, relocated a boiler, or swapped pipework? You’d be shocked how often the bonding gets “temporarily disconnected” and never reinstated.
The Role Of Electricians Vs Gas Engineers
There’s often a grey area on who’s responsible for gas bonding. By law, bonding is an electrical safety function, so it’s under the electrician’s scope.
However, a Gas Safe engineer has a duty to check that bonding is present before commissioning an appliance.
That shared responsibility sometimes leads to the “not my job” problem. The best approach? Communicate early. If the electrician runs the bond, the gas engineer should still visually verify it before finishing. Saves everyone a callback.
Inspections: What They Actually Look For
During a safety inspection or EICR, an inspector checks:
- Main protective bonding is present.
- Correct location (within 600mm of meter outlet).
- Correct size and type of conductor.
- Secure, accessible clamp on clean metal.
- Proper connection back to the main earth terminal.
If any part fails, it’s recorded as a Code C2 fault, which is potentially dangerous. That’s a red flag for any landlord or homeowner needing compliance paperwork.
Evolving Standards And Common Misunderstandings
Over the years, the Wiring Regulations have clarified, but not changed, bonding rules. The main confusion comes from interpretation, not regulation.
For example, plastic pipe inserts at entry points can make it unclear whether bonding’s still required. The general view is: if there’s any metallic continuity between the gas system and the electrical installation, bond it. When in doubt, do it.
Another subtle change is that inspectors are now taking a firmer stance on accessibility. Hidden bonds that were once tolerated are now almost guaranteed to fail.
Practical Tips For Getting It Right Every Time
- Plan bonding early : Don’t leave it as an afterthought during installation.
- Check continuity : Always test between the clamp and the main earth terminal.
- Label it clearly : Use “Safety Electrical Connection – Do Not Remove” tags.
- Take photos : Especially before boxing in or closing off. Inspectors love proof.
A well-done bond doesn’t just tick a regulation box; it shows your workmanship.
Training And Practice Without The Risk
If you’re in the trades, especially if you’re new or training, safe environments to practice are rare. That’s where tools like Tradefox come in.
It’s a simulation app built for electricians, plumbers, and other tradespeople to hone real-world skills in a hazard-free setting.
Perfect for reinforcing tricky areas like bonding and fault testing without putting yourself or your client’s property at risk.
The Bottom Line
Gas meter bonding isn’t complicated, but it’s unforgiving. Miss one detail, and you’ve got a failed inspection or worse, a safety hazard waiting quietly in the walls.
The best tradespeople don’t just follow the rulebook, they understand why the rule exists. Because once you grasp that, you stop seeing bonding as a chore and start seeing it as part of the craft.
It’s the kind of detail that separates a pass from a fail, a call-back from a referral. And in the UK trade game, that’s everything.
