Earthing

GLENNSPARK · Apr 8, 2012

well theres 411.3.1.2 in the OSG...
it is also necessary to consider not just metallic supply pipework but also internal metallic pipework which may have been buried in the ground for convenience, for example, central heating pipework cast into the concrete or buried in the screed of a floor at ground level. Such metallic pipes would normally be considered to be extranious-conductive-parts.....

brman · Apr 8, 2012

Are you going to spill the beans on which scheme so we can all avoid them?

morph · Apr 8, 2012

if the pipework was buried in the ground and through the concrete i can see the assessors point but a quick continuity test would confirm whether the extra bonding is not needed or not

sedgy34 · Apr 8, 2012

Mentioning no names but I'm Nic approved lol

Geoffsd · Apr 8, 2012

I realise the matter has been resolved but an interesting subject.

Is a beam and block floor "the ground". Is it not suspended?

The OSG is just that - a guide.
The regulations state that a service should be bonded where it enters the property (external meter) if extraneous.
If the floor is considered part of the property then the pipes do not re-enter as they did not leave.
No different, in my opinion than being buried in the wall.
Anyway, wouldn't the pipes have been lagged/wrapped to allow for movement?

Remember that the assessor was insisting on 10mm bond, ie. Main Bonding.
So, in his opinion, every gas, water and CH pipe on the ground floor should have been Main Bonded with 10mm G/Y - back to the MET ?

What about upstairs flats with concrete floors? The same?

Also, we cannot be responsible for corrosion after thirty or forty years.
Our meters measure the values today and that is what we use.

It's good that common sense has prevailed but with a less obvious mistake what would have happened?

Engineer54 · Apr 8, 2012

This Assessor is either a fool, or wants to make-up his own rules!! What was his reasoning behind his statement?? Hell you could end up with 30mm or more, bonding this gas pipe!! lol!!!

sedgy34 · Apr 9, 2012

I understand your comments but if you raise an issue of corrosion the install would have to be some years old not 1month

Edd · Apr 9, 2012

I can imagine all the future work this assesor inspects.. insisting 10mm's running from the MET out to every tap, gas outlet, pipe. boiler etc..
it would be like a spiders web. Bet he came up with the idea, spurted it out, and then relised what a pratt he had been but couldnt back track and make himself look a fool!

drew35 · Apr 9, 2012

If the gas pipe in the ground corrodes than an earth bond is the least of their worries. Ask him to show you where this regulations is written.

Guest111 · Apr 9, 2012

drew35 said:
If the gas pipe in the ground corrodes than an earth bond is the least of their worries. Ask him to show you where this regulations is written.

as far as I am aware you are not supposed to bury gas pipes in concrete floors these days.

telectrix · Apr 9, 2012

if that gas pipe corrodes, then there won't be much left after the gas explosion anyway.

Engineer54 · Apr 9, 2012

phil d said:
as far as I am aware you are not supposed to bury gas pipes in concrete floors these days.

Can't see a problem with gas pipes laid in the screed of a concrete floor, so long as it's been wrapped in that grease impregnated tape, (it always used to be) there is very little chance of corrosion!!

I can remember a friend of mine many years ago now, running his kitchen gas pipes in a larger PVC sleeve in the screed, when he renovated/extended his kitchen...

Guest111 · Apr 9, 2012

Engineer54 said:
Can't see a problem with gas pipes laid in the screed of a concrete floor, so long as it's been wrapped in that grease impregnated tape, (it always used to be) there is very little chance of corrosion!!

I can remember a friend of mine many years ago now, running his kitchen gas pipes in a larger PVC sleeve in the screed, when he renovated/extended his kitchen...

Idont think it was to do with the corrosion,I seem to remember it being something to do with damage from drilling or fracturing if concrete flexes as it could have a shearing effect on pipe.

Engineer54 · Apr 9, 2012

I can understand the drilling through, with these kitchen fitters these day's, but not damage due to Screed flexing. as screed sits on top of the concrete floor. They have been installing gas/water pipes in the screed for donkey's years, especially in commercial/industrial premises...

Des 56 · Apr 9, 2012

The plumbers I know still bury it,here is some info I found,it seems eng 54 is spot on with his facts

Pipe in Screed, Corrosion protected pipe
Soft copper tube in plastic sleeve

Installing tube in walls and floors,where copper tube is to be buried in solid floors or walls, the number of joints should be kept to a minimum.
Ideally the tube should be run in a preformed duct (If its in ducting the ducting has to be sealed with a suitable PTFE tape 50% overlap)

If its "ideally" in a duct,it goes to say, it can be done otherwise