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Old Iron Underground Gas Pipe Earthing.

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I came upon this installation today. There is no P.M.E. earth terminal but just a TT rod outside. Ze is about 15 Ohms. But even accounting for the rain recently I can not see that a single 4ft. rod can achieve that low a Ze. The old Denso tape covered iron gas pipe runs underground to the road. It is bonded inside the house as is (presumably) the water pipe. The house is a 1930s aged property. I am noy happy about the final circuits in the consumer unit that do not have R.C.D. protection. Some of these supply outside metal lights on the bungalow wall. I can't imaging in the 80s or 90s this arrangement ever complying. Is the installation relying on the old gas pipe as an earth electrode? I could not do a thorough test today as the gas man was servicing the gas boiler.

Comments please?

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    15 ohms is a perfectly credible electrode resistance for paths through the plumbing - 4ft of rod plus a tens of  m of horizontal pipe to the plastic water meter.

    However, it should have had a VOELCB when new, and some sort of up-front RCD nowadays - a PSSC of about 15A  may just about blow a lighting fuse, but not a fat lot else.

    Mike.

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    15 ohms is a perfectly credible electrode resistance for paths through the plumbing - 4ft of rod plus a tens of  m of horizontal pipe to the plastic water meter.

    However, it should have had a VOELCB when new, and some sort of up-front RCD nowadays - a PSSC of about 15A  may just about blow a lighting fuse, but not a fat lot else.

    Mike.

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