In article ,
Wheelbarrowbob writes
What is the green stuff? How does green stuff manage to
reduce the insulation test readings? On a similar bit of cable without
the reduction in insulation resistance readings would sandpapering the
green stuff off and re-terminating be ok?

All metals when exposed to the atmosphere react and start to corode. Alliminium
reacts almost instantly and over time a white dust appears and this is
alliminum hydroxide. copper reacts the same but turns green, cant remember
wether the green stuff is copper oxide ot hydroxide. the insulation test you
did , did you put put 500V through the conductors ? On a digital ohm meter you
should expect a reading of greater than 999 Mohms or infinity on an analougue
meter. yes , emery cloth and clean and re terminate. I work on the 400KV grid
OHLines and when we get hot joints ( high resistance , which is what your green
terminations are ) we break the joints , file them shiny clean apply a thin
layer of grease and re make the joints then mega them again.

That somehow sounds amusing "we megger them"

Any piccys of your day job on a website Bob?...
--
Tony Sayer