My front door opens on to a very small hall with stairs in front. I want to install a light pendant above the door. At the bottom of the stairs is a double light switch which is for the light at the top of the stairs and for a external light by the front door.
Under the floor above the hall I have located two cables which come up directly from above the switch below. One cable goes off in the direction of the stairs while the other goes towards the outer wall and I assume down to the external light.
I would like the new light to come on when the external light is turned on. Do I just cut into the cable for the external light (power off of course) add a juction box and run a cable for the new light off it to the ceiling rose? If so how do I wire the junction box?