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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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    Have you ever noticed the large nuts on the gas pipes at the gas meter Andy?

    Yes many times - they're unions usually between brass and brass or brass and steel - rather a different beast to compression joints for pipes that have an olive to make the seal - and aren't used to join copper pipes together. Normally even the joint between the brass union itself and the copper pipe is soldered.

    The pipes fail first from rusting through.

    Steel gas pipes certanily don't last indefinitely. Some years ago I had a problem with low gas pressure, which turned out to be caused by "rust" inside the steel gas supply pipe under the garden. Gas engineer explained that it was a common problem and why they'd had to keep replacing the gas distribution system every couple of generations. He said it was caused by "moisture" in the gas causing the inside of the pipes to rust (but I suspect a slightly more interesting chemical reaction).


    Certainly I've noticed a few times now that older houses seem to have at least three generations of gas supplies - the original I guess Victorian Iron ones, later galvanised steel ones (I'd guess 1970s - so probably only had North Sea gas in them) and finally yellow MDPE.


       - Andy.
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    Have you ever noticed the large nuts on the gas pipes at the gas meter Andy?

    Yes many times - they're unions usually between brass and brass or brass and steel - rather a different beast to compression joints for pipes that have an olive to make the seal - and aren't used to join copper pipes together. Normally even the joint between the brass union itself and the copper pipe is soldered.

    The pipes fail first from rusting through.

    Steel gas pipes certanily don't last indefinitely. Some years ago I had a problem with low gas pressure, which turned out to be caused by "rust" inside the steel gas supply pipe under the garden. Gas engineer explained that it was a common problem and why they'd had to keep replacing the gas distribution system every couple of generations. He said it was caused by "moisture" in the gas causing the inside of the pipes to rust (but I suspect a slightly more interesting chemical reaction).


    Certainly I've noticed a few times now that older houses seem to have at least three generations of gas supplies - the original I guess Victorian Iron ones, later galvanised steel ones (I'd guess 1970s - so probably only had North Sea gas in them) and finally yellow MDPE.


       - Andy.
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