What is a 'clamp type current transformer' you mentioned previously. Does the unit not come self contained?
Oops, I realise what you mean now. Clamp as opposed to a ring, which would have to be fitted over a disconnected cable. But if that cable is after the main breaker.......
I have a smallish fuse box with Main Breaker, Surge Protect and RCB, which then feeds to another with all my Mini breakers, so I can easily cut off the power to that box and fit the Monitor. Thanks for help.