In article . com,
"Rob" writes:
My installer (ok, I know it's meant to be DIY, but I was running out of
time doing stuff by myself), despite being given a cable detector and
having the capping outlined on the wall in pencil with the word "WIRES"
written on it, managed to drill a hole right through the middle of the
capping.

AAAAAAAAHHHHHHHHHHHHH!

Same as a JCB digger and an 11,000V cable I mentioned a few
weeks ago. There was no problem until someone showed him where
the 11,000V cable was, and about 3 minutes later, pop and out
when all the lights...

it looks like the drill may have gone in between the cables and may not
have damaged them. Have checked both cables by connecting stuff to
them. They worked and nothing tripped in the CU. Is there some sort of
test that I can do using my Fluke 89 to see if the insulation really
has been damaged?

Someone said I should fill the hole with silicon sealer instead of poly
filler.

Any thoughts?

Since you used capping, can you use the existing cable to draw
a new length in? Or is there enough slack to pull the potentially
damaged cable area through to a box where it can be inspected?
This is what I did above my bathroom ceiling when a friend who
was helping me screw up the plasterboard put one of the screws
straight through the conduit to the central light BESA box.
As it happened, the cable was unharmed, but I would not know that
without pulling it through enough to inspect it.

--
Andrew Gabriel