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bonding a short section of water supply pipe

wallywombat
In a victorian terrace house, a lead water supply pipe enters the damp cellar, runs about a meter along the wall to the main brass stopcock, then converts to plastic pipe before exiting the cellar to the rest of the house (which is likely to be a mixture of copper and plastic). The stopcock is a couple of feet away from the CU. Should the supply pipe be bonded? My feeling is no, but I'd be interested in other opinions.


While I'm on the subject, a more general question. Why must any bonding be done after the main stopcock? For example where the supply tees off immediately after the stopcock, is it better to bond one of the tees, or bond just before the stopcock? Where there is a long run of supply pipe before the stopcock, is it better to bond after, with a long MPBC run back to the MET, or bond it near the MET even where that's before the stopcock?
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    AJJewsbury:
    When?

    When these diverted N currents you're worrying about are trying to make their way back to the star point. They're just as likely to try and get there via the lead sheath of a cable than a gas pipe (probably more so these days as most gas mains have been replaced by plastic).


    BTW around here most earths are connected to the lead sheath by a pipe clip of some kind - the old YEB didn't seem to like hot works and appeared have their own not quite BS 951 variant. There's loads of PILC still in service (often upraded to 80A or 100A fuses too).


      - Andy.


    The diverted neutral currents can be conducted by the armour of the P.I.L.C. cable.


    For a domestic P.I.L.C. service cable, the earth fault currents will be limited in size by the protective device, say a 30 Amp fuse wire. So the lead will not have to carry hundreds of Amps. as it may for a lead gas pipe.

    IET Forums - PILC Earth Clamp (theiet.org)


    Z.

     


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  • 0
    AJJewsbury:
    When?

    When these diverted N currents you're worrying about are trying to make their way back to the star point. They're just as likely to try and get there via the lead sheath of a cable than a gas pipe (probably more so these days as most gas mains have been replaced by plastic).


    BTW around here most earths are connected to the lead sheath by a pipe clip of some kind - the old YEB didn't seem to like hot works and appeared have their own not quite BS 951 variant. There's loads of PILC still in service (often upraded to 80A or 100A fuses too).


      - Andy.


    The diverted neutral currents can be conducted by the armour of the P.I.L.C. cable.


    For a domestic P.I.L.C. service cable, the earth fault currents will be limited in size by the protective device, say a 30 Amp fuse wire. So the lead will not have to carry hundreds of Amps. as it may for a lead gas pipe.

    IET Forums - PILC Earth Clamp (theiet.org)


    Z.

     


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