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Main earth bonding to gas pipe


stephenh

Question

In a ground floor flat with a cellar at the front of the house a steel gas main (40mm o/d) enters the cellar from the street, passes the DB, and somewhere, hidden in the house structure, it splits up into 3 x 25mm O/D to service 3 flats.

One of these steel pipes comes out through the rear outside wall of the ground floor flat and connects to an external gas meter. After this 22mm copper pipe re-enters the flat.

There is a 10mm earth cable looped from one side of the meter to the other with standard earth clamps.

In the cellar a 10mm earth goes from the main earth terminal by the DB, to the main incoming 40mm steel pipe.

Is this satisfactory ? The wiring is approx. 7 years old.

I am a surveyor, not a sparks and don

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10 answers to this question

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We have to go to the customers side of the meter as the meter may well have rubber/plastic washers that insulate one side of the pipework from the other, or as is fairly common a bendy/flexi pipe is used to connect service side to the meter & tend not to have reliable continuity ....

Having said that the way you describe the pipe run I would have put a connection to the pipe in the cellar aswel...wouldn't have looped across the meter though.

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PC Electrics

I would say "no, not okay", because the main protective bonding is supposed to be made direct from the MET to the consumers side of the gas meter. This installation seems to be using the gas main as the MPB conductor, which is also a no no.

If the 'gas board' were to replace the steel gas main with plastic (which they are entitled to do as it is their pipe) what bonding that does exist would be gone.

On a PIR this would be a code 2. Needs fixing pronto, the installation is technically unsafe (unsatisfactory).

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im having real problems picturing this one, but to me it doesnt sound like there is a problem here???

the bond is made as near as practically possible, and the person who carried out the bonding has been concerned about the length of pipe before the meter and so bonded on both sides of it, no problem as long as clamp isnt on the flexi. As said if the meter is removed there may be a chance of a unbonded length of steel pipe hence bonding both sides.

Or have i pictured this one wrong?

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Zeespark

Should be one single bond on consumers side of supply, as near to 600mm as poss from source or nearest bend.

AndyGuiness Drink

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read a further 10 times and understand now, completely agree with PCs comments. I read it as the bond ran to the external gas meter and looped across.

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erm......

The "cross-bond" at the meter is atypical of some gas engineers; who were told by the (then) CORGI that this should be done (only reason I know is that a plumber accused me of shoddy work because I hadn`t cross-bonded his gas meter. Pillock!)

If 3 flats are being serviced; do they each have a consumer unit? If so; then they should have bonds from their individual METs, to their respective gas meters.

If there is only one meter; and only one DB; then the bond should be on the 22mm copper work. I don`t see an issue with the 40mm steel being clamped to the DB in the cellar AS WELL though.

HTH

KME

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green-hornet

Its common practice in homes of multiple occupancy, to main bond at entry ie basement, and from each db to each gas supply.

If this bond to the main 2" gas main is the only bond, then I would say it is wrong.

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PC Electrics
Its common practice in homes of multiple occupancy, to main bond at entry ie basement, and from each db to each gas supply.

If this bond to the main 2" gas main is the only bond, then I would say it is wrong.

That's the way I'm reading it Green.

I'm reading it that there is NO continuous 10mm from the consumers side of the gas meter to the MET. The steel pipe is effectively the main protective bonding conductor. Wrong, wrong, wrong.

Perhaps the OP could post some pics?

OP, I believe Sen, on the 'other' forum is misinterpreting your post (assuming my interpretation is correct).

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PC Electrics;81197]

"I'm reading it that there is NO continuous 10mm from the consumers side of the gas meter to the MET. The steel pipe is effectively the main protective bonding conductor."

This is exactly the case. A direct wire connection would be 25m ! - through the whole length ( depth?) of the house....

"Wrong, wrong, wrong." OK...not up to code, but is it dangerous? The wiring was done 7/8 yrs ago so not up to current standards I suppose.

"Perhaps the OP could post some pics?"

Not my flat - won't be visiting for some time.

"OP, I believe Sen, on the 'other' forum is misinterpreting your post (assuming my interpretation is correct). "

You are right - he is.

Many thanks for your time / input

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PC Electrics

This is exactly the case. A direct wire connection would be 25m ! - through the whole length ( depth?) of the house....

Nothing odd or unusual about that! Leccy and water services are often at opposite corners of a house. Still needs bonding properly.

"Wrong, wrong, wrong." OK...not up to code, but is it dangerous? The wiring was done 7/8 yrs ago so not up to current standards I suppose.

'Dangerous' is a powerful word and one I prefer to reserve for situations that truly deserve such a description.

In IEE terminology your installation is 'unsatisfactory'. I would say 'unsafe' even

Todays requirements are no different to 8 years ago for protective bonding, so it was done wrong in the first place.

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