As long as you shut-off all the appropriate fuses and terminals in what we Brits like to call a "Fuse Box" then all should be fine.
The quality of the wall concerns me, and I hope before all this you used a Voltage/Continuity tester, otherwise I'd be banging me head off the walls. :chair:
Hopefully all is well, all I can say about you Yanks is the obsessive, and dangerous and flimsy use of Cable-end caps. Oh my days.... :crying: