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I've finally got an electrician lined up to do the 'equipotential bonding' on my gas meter as flagged by my heating engineer.
I've also just had an appointment confirmed for my energy company to come and swap the gas meter out for a smart one.
Do I need to sort the bonding before the meter is swapped out or would that be sorted as part of the swapping out process? Or maybe it can be swapped out as it is but sort the bonding job after?
Pretty sure ours isn't bonded and we had both electric and gas meters updated to smart meters earlier this year. The chap didn't mention it and he was very thorough - didn't like the existing pipes from the meter, so replaced them all.
I have, however, bonded all the pipes (gas / water) inside the house so everything is connected. A lot easier to do inside the house as the gas pipe passes underneath the leccy meter, so only need 60cm of earth cable.
The connection will be on the gas pipe on "your" side of the gas meter and the replacement of the meter shouldn't need any alteration to the existing pipework and the bonding connection so could be done before or after.
The responsibility of the bonding is the consumer's so they will not do this as part of the meter replacement and I would say that it unlikely they would ever comment as the location of the bonding termination could be removed from the meter and still comply with the wiring regulations.
Thank you. Good to know the things don't interfere.
Does it need bonding?
If the incoming gas pipe is plastic,the one that comes out of the ground, then you probably dont need to do it.
There's an old saying:
Safety regulations are written in the blood of those who died in a gas explosion caused by static discharge from a plastic pipe in a system that didn't have equipotential bonding.
Or something like that.
I joke, of course, but the regs state:
BS 6891, Clause 8.4.3.1
“A gas installation within a property with an electrical supply shall have a main protective bonding conductor connecting the pipework to the electrical installation’s main earth terminal, as specified in BS 7671.”
BS 7671, Regulation 544.1.2
“The main protective bonding connection to any extraneous-conductive-part such as gas, water or other metallic pipework or service shall be made as near as practicable to the point of entry of that part into the premises. Where there is a meter, isolation point or union, the connection shall be made to the consumer’s hard metal pipework and before any branch pipework. Where practicable the connection shall be made within 600 mm of the meter outlet union or at the point of entry to the building if the meter is external."
Shall is not should. Imperative not suggestive.
It's my heating engineer who's flagged it on 2 successive gas service/maintenance checklists.
Sounds like it's something worth sorting?
TheflyingOx - this was always my understanding as well. As far as I’m aware it’s to be continuous to the gas meter and incoming stop tap in 10mm2 cable.
Sounds like it’s something worth sorting?
As long as the gas pipework is bonded somewhere you've gained all the benefit. There's no actual point in running an earth cables miles to the meter itself, if the gas pipe passes closer to the meter at some point as the resistance difference between the two will be negligible.
I suspect in 99.9% of cases, the gas pipe will be earthed for you in the boiler itself (which will be earthed), so it's a pretty slim marginal gain earthing the pipe as well.
As said above, if the incoming pipe is plastic then no need to bond it as any pipe work in the house will be at the same potential to the main earth. The purpose of bonding metallic incoming pipes is that they are basically big earth rods so you need to connect them to the main earthing terminal to stop the possibility of two different resistances to earth occurring
How do I know it's bonded somewhere? All I know is that my heating engineer has flagged it twice and says I need it doing.
When my meters were replaced the fitter left a card saying my installation was unsafe and I needed to fit bonding. In fact the bonding was there, within 60cm, on the inside face of the wall, which he couldn't see (the meters are in a cabinet built into the outside face of the wall).
So I would get it done now, but just make sure it's not connected so close to the meter that it would be affected by swapping it.
Main incoming pipe isn't plastic.
I colour in for a living, so don't follow much of this!
I'll get the meter swapped first, then sort the bonding. Thanks all.
There's a danger of confusing low-pressure gas regs (BS6891) with electrical regs (BS7671)
BS 6891, Clause 8.4.3.1“A gas installation within a property with an electrical supply shall have a main protective bonding conductor connecting the pipework to the electrical installation’s main earth terminal, as specified in BS 7671.” (my bold)
If BS7671 doesn't specify it, then it isn't needed. "To summarise, if any doubt exists following visual inspection, it could be determined by measurement and calculation if a part is deemed to be considered an extraneous-conductive-part before deciding whether to connect it to the main earthing terminal. Each installation is required to be assessed individually and a decision made, which will provide the greatest degree of safety, and the ultimate decision rests with the designer of the installation." https://electrical.theiet.org/wiring-matters/years/2019/75-may-2019/to-bond-or-not-to-bond/
and with diagrams
Main incoming pipe isn’t plastic.
Probably a moot point in this case 🙂
How do I know it’s bonded somewhere? All I know is that my heating engineer has flagged it twice and says I need it doing.
Well you basically can't ever know unless you remove all the floorboards etc as someone may have just bonded under the hallway floor etc.
However, most likely you can just trace the earth wires from the earthing block beneath the meter and see if it's directly connected.
You could just stick a multimeter on it and see if there is a voltage difference between the gas pipe and mains earth. If you see a few volts, then it's not bonded, if it's milli-Volts then measure the resistance and I bet it's close to zero, so bonded somewhere.
As far I can see the actual risk you're trying to mitigate is something lives comes loose and touches the gas pipe. Gas pipe is now live. Someone touches gas pipe and gets a shock. If the gas pipe is earthed, that will just trip either the RCD or the fuse, so stopping someone getting a shock. The gas pipe will be earthed in the boiler, so the actual risk is very small, you'd have to have a metal gas pipe with a plastic adaptor on the end which isolated it from the boiler at the connection, which would be very odd. You'd also need an exposed gas pipe eg our runs under the floor, then pops up and runs behind the kitchen cabinets, so no one can see it, let alone touch it.
If the gas engineer can't physcially see the bonding at the gas meter they flag it. Ours is bonded under the floor where it enters the house so not visible. Still gets mentioned every time though. Kind of wish I'd just fed it through the wall for the extra metre or so to the outside cupboard