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gas installation pipe bonding [again]

psychicwarrior
"My head is in a spin, my feet dont touch the ground..."  - I think I am just wanting to unload my head to the almighty interweb (at least it is not to that facebook thingy) and in that, it will heal. :)


A description: a gas meter is in its cupboard outside on the side of a house and the service pipe coming out of the ground to it, at this stage, I am assuming to be conductive (or not plastic). The bare copper installation pipe from the meter, comes out of the top of the cupboard, goes  up the wall and around the outside of the house (at a touchable height) to the opposite side, a run of about 12 metres, where it enters the building though the wall and attaches to the boiler.  I am told this is quite common.


As an aside, for now, the visiting gas engineer said to the property owners, that because of how it is run, he wanted to see some bonding connected inside the meter cupboard on the installation pipe side , not elsewhere, or it would get a notice. *


What I am curious about is the approach to running an accessible [and conductive] pipe aroung the outside of a house (rather than getting it inside immediately) and bonded to the MET when there could be a fault on the installation.  It must be in the similar vein as  a small 'class one' light fitting being installed on the wall outside, that this is seen as an allowable potential shock risk even when it would be accessible for such a distance as it were when 'lively' ?   Or am I over-thinking this, or just getting it all wrong (as is my wont) with a "there is no issue here actually".


Regards

Habs


* I am starting to dislike use of some partial plastic pipe alterations in properties.  Keeping it brief as this is just part of the 'aside' comments: there are plastic sections a little after the copper 'out/return' pipes on the boiler which disappear into the house structure to goodness knows where.  Something else, or the copper pipe still visible elsewhere servicing radiators and so forth, seems to be keeping those parts extraneous. With a lot of pipe 'buried', it is quite tricky to spot whats going on.   As it happens, there is a MEB cable clamped to a copper pipe feeding a radiator on an internal wall, which then runs through the wall to the  MET on the other side.  This would seem to be doing its job for all the extaneous parts (gas and water connected) when assessing with it connected/disconnected. The connection is not in the ideal position, open to risks of being disconnected from more [future] alterations but it is working and perhaps the previous sparks decided this was the best to be done in the circumstances.  Its a bonding conundrum to find a good solution - if only it were all plastic, or still all copper...ho hum.
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    The bond to the rads may well be just that the radiators were not really earthed and for supplementary bonding rather than main.

    After all there is nothing in the regs that stops you earthing things that do not need it, and a lot of folk from the era of the 15th edition (supplementary bonding  in kitchens) still feel better to err on the side of 'earth everything'  without thinking too deeply- I suspect it is left over from some previous work, and it does no harm, just confuses.

    I think your logic is correct, you only really need to guard against credible fault conditions.

    And yes, you will have PME earth on the pipe outdoors, but to put that risk into perpective there are many bus shelters and lamp-posts with PME mains supply up and down the land, and there are no early morning teams required to remove the electrocuted bodies from beside them, so it is an accepted small risk. It is not like the car, boat or caravan situation that is fed by flex, and folk will repeatedly grab the handles while in good contact with terra-firma.

    Regs wise it is going to be hard to satisfy everyone.

    Actually assuming the boiler CPC is in good shape, you probably already do have mains earth voltage outside, just not in a clearly visible and easily inspected sort of way.

    I'd be tempted to put a bond in a place for water and gas that is easy to do and available to inspect, and then worry no further. If it is connecting to something that by dint of an IJ or plastic pipe underground did not strictly need it, no one will be surprised or upset.

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  • 0
    The bond to the rads may well be just that the radiators were not really earthed and for supplementary bonding rather than main.

    After all there is nothing in the regs that stops you earthing things that do not need it, and a lot of folk from the era of the 15th edition (supplementary bonding  in kitchens) still feel better to err on the side of 'earth everything'  without thinking too deeply- I suspect it is left over from some previous work, and it does no harm, just confuses.

    I think your logic is correct, you only really need to guard against credible fault conditions.

    And yes, you will have PME earth on the pipe outdoors, but to put that risk into perpective there are many bus shelters and lamp-posts with PME mains supply up and down the land, and there are no early morning teams required to remove the electrocuted bodies from beside them, so it is an accepted small risk. It is not like the car, boat or caravan situation that is fed by flex, and folk will repeatedly grab the handles while in good contact with terra-firma.

    Regs wise it is going to be hard to satisfy everyone.

    Actually assuming the boiler CPC is in good shape, you probably already do have mains earth voltage outside, just not in a clearly visible and easily inspected sort of way.

    I'd be tempted to put a bond in a place for water and gas that is easy to do and available to inspect, and then worry no further. If it is connecting to something that by dint of an IJ or plastic pipe underground did not strictly need it, no one will be surprised or upset.

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