Bonding for new gas meter install

[MattChan]

SGN have just moved my gas meter from a recessed enclosure to a semi buried unibox style enclosure which sits 75mm in the ground.

The input pipe is plastic and the oulet will be copper (when its finally connected up). The sleeve for the gas pipe through the cavity wall is already in place and comes though the wall just above where it will join the old black iron pipe in the floor screed. This will be behind a box that will hold the cistern for a toilet so wont be accessible.

Questions:
* Does this need bonding as the supply is plastic?
* Is the black iron in the screed effectively the same as the supply being in metal so bonding is required?
* As the bond wouldn't be accessible for the short length of internal exposed pipework behind the box is it acceptable to drill a hole in the unibox and insert a stuffing gland for the bond to go through or should the enclosure not be drilled in any way?

 

[EFLImpudence]

The now plastic supply pipe obviously doesn't require bonding, but

the "old black iron pipe in the floor screed" might.
Can't tell on the internet; it would need measurements; but bonding gas pipes unnecessarily is not a problem because they will be earthed by the boiler anyway.

Pipes should be bonded "at the point of entry- where practicable" so that might be where the iron pipe can be accessed.

 

[MattChan]

Pipes should be bonded "at the point of entry- where practicable" so that might be where the iron pipe can be accessed.

I had read that but once the works are complete the pipe will only be accessible as 22mm copper outside (for about 100mm from meter box to sleeve) and in the meter box and as 15mm copper In the upstairs airing cupboard.

Between the two its hidden and it goes into black iron for about 7m in the screed and T's off to the gas hob and then up some boxing in the corner of the kitchen before landing in the airing cupboard above.

I've read its preferable to bond indoors within 600mm of entry but also read that some gas safe guys expect to see it at the meter and that that is another option. But then i see things about not making holes in boxes!

 

[EFLImpudence]

I've read its preferable to bond indoors within 600mm of entry but also read that some gas safe guys expect to see it at the meter and that that is another option.

The 600mm. does not relate to the point of entry. Indoors or outdoors make no difference.
Gas Safe guys (and lots of electricians) do not understand bonding.

But then i see things about not making holes in boxes!

Ask the installers about that.
Can you not feed the bonding conductor through the pipe sleeve?

 

[MattChan]

Thanks EFLI.

The bonding conductor going to the old meter location is in the cavity so i was just going to pop a hole through the outer leaf near to the gas sleeve and fish the bond wire through?

 

[EFLImpudence]

I don't see how they could object to that.

 

[MattChan]

would you normally sleeve a bond through a single leaf? Any minimum distance recommendations from the gas sleeve / meter box?

 

[CBW]

This any use to you? https://registeredgasengineer.co.uk/technical/technical-bulletin-102-2/

 

[EFLImpudence]

would you normally sleeve a bond through a single leaf?

No,

Any minimum distance recommendations from the gas sleeve / meter box?

Not sure what you mean.

As said, the requirements are to bond "at point of entry where practicable".

'Where practicable' means where it would achieve the desired effect.

For example, if your pipe comes into the house under floorboards and does not become visible (or touchable) until it comes up through the floor somewhere, then you could bond where it emerges from the floor or outside where it enters the wall.

 

[MattChan]

Ah I meant i know the meter box has to be 150mm away from air bricks in case of escape of case so wasnt sure if the cable entry had to be 150 away too.

 

[MattChan]

This any use to you? https://registeredgasengineer.co.uk/technical/technical-bulletin-102-2/

Very informative. May just need some help with the interpretation in my application!

 

[EFLImpudence]

Ah I meant i know the meter box has to be 150mm away from air bricks in case of escape of case so wasnt sure if the cable entry had to be 150 away too.

Well, it could come through the air brick if you weren't fussy.

You wouldn't just leave a big hole where the cable went through the brickwork; it would be filled.

 

[SUNRAY]