Just after a bit of advice on a fused spur query - A customer's having an extension done and he wants some sockets and a light putting in it. There's a feed for one socket going into at the moment from a previous outside socket (ring main). I'm going to extend this ring main to incorporate 2 more double sockets. I'm also going to take a fused spur off this ring main to feed the light. Regarding this fused spur - Can it be concealed (for example in the ceiling) or does it have to be visible?