Help!! I am installing fluorescent lights in loft. I tried pulling spur from junction box in loft and leading via 5 amp fuse to new light switch then on to my loft lights. Problem - this is interfering with lights in landing - when landing lights off and I turn on loft lights, landing lights flicker on and off as fluorescent motor starts - when landing lights on, no power to fluorescent light circuit. I tested power and find that when landing lights off there is power between + and - in junction box but when landing lights on there is just power between + and earth. What is going on, where am I going wrong and how do I resolve it????