2 x 10mm in Isolator.

[skatingsparks]

The other way is maybe use a piece of 16mm RVK "welding cable" which will have a higher rating and be able to carry the current -

Good thinking. I might go with that after I have spoken to him as to see what he thinks is 'inadequate'.

[JustJohann]

Just remember that the real cable used for welding machines are not rated for 240v. But your probably talking of the flexible cables they use in panels.