Earth Bonding - LPG Pipe That Does Not Go Underground

[Dartlec]

Thanks for all the comments. I don't strictly need a gas safety certificate for our own house, but if the need arises I could use a different gas fitter. This guy also wanted to see a CO alarm, even though the actual guidance says ..


However I've not been able to put my finger on the actual legislation governing that requirement. My quote comes from the "Tolerable Standard Guidance
Tolerable Standards

The legislation is significantly tighter in Scotland than in England, where we have the catchily titled "The Smoke and Carbon Monoxide Alarm (England) Regulations 2015" which is only for landlords and specifies:

a carbon monoxide alarm is equipped in any room of the premises which is used wholly or partly as living accommodation and contains a solid fuel burning combustion appliance

I'm not expert on the Scotland legislation, but it does seem to match with what you say about carbon monoxide and "tolerable standards" in most places.

From an 'official' page: Fire and smoke alarms: changes to the law - https://www.gov.scot/publications/fire-and-smoke-alarms-in-scottish-homes/

If you have a carbon-fuelled appliance – like a boiler, fire, heater or flue – in any room, you must also have a carbon monoxide detector in that room

Which isn't entirely clear whether it includes cookers.

Though to be honest, they are so cheap I'd probably put one in just for peace of mind.

Re the bonding - It's always useful for when someone demands something, to request in writing the legislation or guidance they are using to base their decision on. A tick box on an inspection report is not a good enough justification.

One possible option going forward would be to get an electrician to inspect - and specify in writing that bonding is not required in your circumstance - something you could show any future gas fitter.

 

[littlespark]

I often wondered why Co detectors were not needed for a cooker...

Is it something to do with the holes that the flame comes from? Or the fact that kitchens should have an extractor?
A boiler is a sealed unit... the only place Co can come from is a leak in the flue or the boiler itself...

Doesnt explain why you need one for an open fire

 

[Dartlec]

I often wondered why Co detectors were not needed for a cooker...

Is it something to do with the holes that the flame comes from? Or the fact that kitchens should have an extractor?
A boiler is a sealed unit... the only place Co can come from is a leak in the flue or the boiler itself...

Doesnt explain why you need one for an open fire

Perhaps the thinking is that cookers are not usually left on while people are sleeping, which a fire/boiler could be?

I'd guess that it needs a prolonged period of formation to build up enough CO to cause a risk to someone (or indeed to set off a sensor)

CO as I understand it is formed from the incomplete combustion of fuel (wood/coal/propane/natural gas), so can't occur unless there is a combustion process, which there isn't when a cooker isn't being used.

I've always been slightly confused by combined CO/Smoke alarms in the ceiling, since I understood that CO was heavier than air, but a quick google suggests that's wrong. Though this site claims the wall a couple of feet below the height of the ceiling is best...

 

[littlespark]

I've always been slightly confused by combined CO/Smoke alarms in the ceiling, since I understood that CO was heavier than air, but a quick google suggests that's wrong. Though this site claims the wall a couple of feet below the height of the ceiling is best...

I know LPG in the calor gas bottles is heavier than air. Leftover knowledge from caravan site days where we had to ensure there was ventilation in peoples decking for just such reason. I assume natural gas, paraffin, propane, butane are all heavier.

Burned exhaust gas must be lighter than air, as some flues exit vertically upwards.

 

[aesmith]

Thanks for all the comments. Can anyone clarify a bit about unnecessary bonding possibly introducing hazards? In this installation the appliance is earthed but I don't think the gas flexible hoses are conductive meaning there's no electrical path to the gas pipework or the cylinders. I can check although that would just be with a multimeter.

 

[LastManOnline]

Thanks for all the comments. Can anyone clarify a bit about unnecessary bonding possibly introducing hazards?

One example.The kitchen sink continued to be bonded in many countries despite the water pipes connected to it no longer been metallic.This meant that under certain fault conditions (open PEN) a piece of metal that was actually electrically isolated from earth and posed no danger to the homeowner is now live at 230 volts and could pose a potential hazard if the floor is poorly insulated.

I can check although that would just be with a multimeter.

You cannot effectively test if metals are extraneous with a multimeter.You need an insulation resistance tester.

 

[aesmith]

OK thanks. We're on a TNS supplier (verified on-site by the DNO) in case that makes a difference. Can a scenario similar to the broken PEN arise?

 

[LastManOnline]

OK thanks. We're on a TNS supplier (verified on-site by the DNO) in case that makes a difference. Can a scenario similar to the broken PEN arise?

A TNS supply?.Congratulations.Thats the "creme de la creme " of available electrical supply systems in my view.
Basically you have all the advantages of a TNCS system but none of the downsides.No worries about open PEN faults.No need for open PEN sensors.

 

[littlespark]

I prefer a PMSL supply myself.