The landing light is controlled by a 2way switch in hall and 1 way on landing. How easy is it to change the 1 way into a 2way so allowing me to switch the hall light on and off from the landing. At present this can only be done downstairs in the hall.

RB, February 2010

It should be fairly easy if there is enough space in the conduit.
You just need 3 live wires between the two switches connected to the same terminals at each end.
At the existing switch move the wire from COM to L2.

You may need a drop of liquid soap to help the wires slide down the conduit.

Adam, February 2010

Can I feed a cable down the existing conduit in the wall?

rosemary, February 2010

You wish to make the existing one-way downstairs light in the hall to be two-way switching. This will mean installing another lighting cable between the two switch stations.

You will need to install a two-gang switch upstairs and run lighting cable between the two switch positions. This may mean chasing out the existing cable channels so that you might add the new cable run - and make good - fill plaster decorate etc. Floorboards may aslo need to be lifted to route the new cable.

Is the effort worth the reward?

Good luck...

Peccavi, February 2010