Bonding within 600mm of gas meter.

[sinewove]

Have seen several threads on here regarding battles with gas engineers and sparks re the above.The regs state the the earth clamp shall be fitted within 600mm where "practicable",but then goes on to state before any branches in the pipework.Should the word practicable also apply to any branches in the pipework,since they are not always visible in the real world?
Regards,S

 

[littlespark]

If gas fitters etc know the regs so well, they would install the pipework so there was a suitable length of pipe to fit the earth clamps... within 600mm... before any branches etc....

Nothing is perfect... so you fit the clamp where you can.....

The physics behind it is to earth the metal pipe as close as possible to where it reaches the "mass of earth" outside.... and if that means on the "wrong" side of a t-branch... then so be it.

 

[pc1966]

If there is a visible branch and you can't connect before it, you could bond to both pipes that exit the branch to achieve the same electrical goal (i.e. that a poor electrical joint in the pipework does not lead to half the pipework being at a significantly different potential to the MET under fault conditions).

 

[timhoward]

The physics behind it is to earth the metal pipe as close as possible to where it reaches the "mass of earth" outside

I know what you mean but I’m trying to decide if I agree with the way you’ve explained that that as it can be taken to read ‘the nearer the mud the better’ in favour of being nearer the point of entry, as per the first half of 544.1.2.
The bit about the meter being outside is often completely ignored by our gas friends.

 

[R-fur]

With an outside meter and a TNC-S system you are exporting the neutral, such that someone standing on true earth and touching the gas pipe could get a shock if there was a fault in the neighbourhood.