I didn't write that clearly in my previous post about the 10mm Earth, I meant to my stop
cock.
The original installation should be ok as the original shower had this 40A supply and the max rated socket in the workshop will now be only 32A, this socket may never get used anyway as my current TIG welder uses a 16A supply but if I ever upgrade the welder I may buy a 32A water cooled TIG next hence the reason I want this socket.
Some of you have said put the 10mm supply cable on the non protected side of my house CB and fit a RCD/MCB CB in my workshop but then the supply cable between both CB's won't be RCD protected?, does it need RCD protecting in my loft?.
I appreciate you won't get any nuisance tripping of the house if it's wired this way as the RCD will be in the workshop.