In article ,
Stefek Zaba writes:
Andy Hall wrote:

For the one that you have, there should be some strips of nylon with
castellations with it which you cut and place around the cut out
section. You should use them and not allow the cables to come into
direct contact with the cutouts.

If the grommet strip is missing, you can buy lengths at any electrical
trade counter, and at the bigger sheds (e.g. been-n-queued whorehouse).
It's called grommet strip ;-)

....and if you're really stuck, T&E sheath stripped by running a
knife down the edge of the earth looks remarkably like grommet
strip and is guaranteed not to have a nasty reaction with the
T&E sheath of the cables, but would need glueing in place (as
indeed should grommet strip be).

--
Andrew Gabriel