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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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    411.3.1.2 says, regarding main protective bonding,  "IN EACH INSTALLATION"..... so we are not concerned with anything OUTSIDE the installation are we.



    But inside and outside the electrical installation isn't the same a inside and outside the building - as the electrical installation often extends outside (the building)  these days.

     

    It's worse than odd.


    It both defeats the purpose of the bonding rendering it useless and leaving the extraneous-conductive-part not bonded, and 


    the insulating section makes the consumer's pipework NOT an extraneous-conductive-part which therefore does not requiring bonding.



    I'm not quite so pessimistic. If there's no IJ then then bonding works perfectly well.


    If there is an IJ then either the consumer pipework is still extraneous (e.g. as it picks up an Earth potential from within the installation) so the bonding remains required (and effective) or it isn't extraneous in which case the bonding is wasted but likely does no harm (as it'll likely be connected to the MET via boiler or hob c.p.c.s anyway). At least we don't have to contend with the issue of push-fit plastic joints being retrofitted willy nilly on internal gas pipes.


    Yes there is the issue that the short length of gas supply pipe before the IJ isn't bonded - and perhaps ideally it could be shrouded in insulating material to reduce the shock risk. But as we can't really tell if an IJ has been fitted - or just as importantly whether one will be fitted at a later date - bonding to the consumer's side seems like a reasonable (if far from ideal) compromise.


    This particular problem will likely disappear anyway as the final few remaining steel gas service pipes get replaced by plastic, and then North Sea gas runs out.


        - Andy.
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  • 0

    411.3.1.2 says, regarding main protective bonding,  "IN EACH INSTALLATION"..... so we are not concerned with anything OUTSIDE the installation are we.



    But inside and outside the electrical installation isn't the same a inside and outside the building - as the electrical installation often extends outside (the building)  these days.

     

    It's worse than odd.


    It both defeats the purpose of the bonding rendering it useless and leaving the extraneous-conductive-part not bonded, and 


    the insulating section makes the consumer's pipework NOT an extraneous-conductive-part which therefore does not requiring bonding.



    I'm not quite so pessimistic. If there's no IJ then then bonding works perfectly well.


    If there is an IJ then either the consumer pipework is still extraneous (e.g. as it picks up an Earth potential from within the installation) so the bonding remains required (and effective) or it isn't extraneous in which case the bonding is wasted but likely does no harm (as it'll likely be connected to the MET via boiler or hob c.p.c.s anyway). At least we don't have to contend with the issue of push-fit plastic joints being retrofitted willy nilly on internal gas pipes.


    Yes there is the issue that the short length of gas supply pipe before the IJ isn't bonded - and perhaps ideally it could be shrouded in insulating material to reduce the shock risk. But as we can't really tell if an IJ has been fitted - or just as importantly whether one will be fitted at a later date - bonding to the consumer's side seems like a reasonable (if far from ideal) compromise.


    This particular problem will likely disappear anyway as the final few remaining steel gas service pipes get replaced by plastic, and then North Sea gas runs out.


        - Andy.
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