A lot more complex than I thought!
I need to fit a 5 pin 3 phase plug.
Done it before a few times but what do I do with the spare wire.
Right hand side of picture.
I think it is a negative for the 240v socket on the back.
The pass through is only 4 pins. I suspect the machine would have had a 4 pin plug originally?
The other wire is of a different gauge. It connects to the neutral on the 13amp plug by the look of it.
The only time that you need a neutral (5th wire) on a 400v 3ph machine is if there is any 240 stuff on it. Sometimes some of the control circuits need 240v. If you don't need the 13a socket disconnect the neutral wire at both ends & insulate it. Then try the machine, if everything still works, job done.