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rubber insulated cloth covered tinned copper submain cable in galv. conduit.

Legh Richardson
Had a look at an installation which has a submain running approximately 25m to supply a kitchen.

We thought umm this looks interesting, cut a slice off at the output of the switched fuse and re-terminated. The cloth, and rubber appears to be in reasonable condition for what appears to be nearly 70 years old. An insulation test at 500V gave a reasonable result (>500M) and a leakage test gave the same, 0.41mA.

The cable is out of date but appears to be still serviceable. It is not heavily used and the ambient temperature is generally quite low. I think I might advise that the cable is replaced by a newer edition or at least regularly checked every year. Has anybody got any other ideas?


Legh
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    I noted the same with the TRS cable in our house. The ends were perished to all hades, and held together with sleeving, tape, and paper in a couple of instances... the main runs through the attic were fine. Rubber can be remarkably resilient. The fact it is in metal conduit also adds to the safety. Ensure the conduit is well bonded (given the age, i'm assuming it forms the CPC anyway?), take some high current Zs readings, to make sure corrosion isn't messing up the continuity...Any breakdown in service will simply cause ADS to occur as expected. In short, it's fine.
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    I noted the same with the TRS cable in our house. The ends were perished to all hades, and held together with sleeving, tape, and paper in a couple of instances... the main runs through the attic were fine. Rubber can be remarkably resilient. The fact it is in metal conduit also adds to the safety. Ensure the conduit is well bonded (given the age, i'm assuming it forms the CPC anyway?), take some high current Zs readings, to make sure corrosion isn't messing up the continuity...Any breakdown in service will simply cause ADS to occur as expected. In short, it's fine.
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