I am looking to add a new light and the best access I have is from an adjacent room's light fitting. This ceiling rose has 3 supply lines, which I assume is a supply in, supply out and a spur.
Is it OK to add another spur from this fitting?
I am also unsure where this spur goes as the other light fittings also have 2-3 supply cables. How would I find out which of these 3 supply lines are the in & out? Is it a matter of disconnecting 1 and seeing which lights are not switching on?