I have installed security lights before on my garage and used the small fuse box/cu to take a feed off the internal garage light supply. Now I want to install a 150w security light on the house. Is it ok to do so using the appropriate 3 core flex but terminate it in a plug that is 5amp supplied and then plug it into the internal wall power supply socket? It would appear messy to me to try and terminate it at the mains circuit breaker box in the study? Thanks..