Staircase Lighting

Because we had re-planned for a spiral staircase early in the build process we were able to design our electrics around that. The downside is that now we have abandoned the spiral, everything is in the wrong place. Seven double sockets, a TV point, a phone point, an ethernet outlet and a wall light will either have to be abandoned or moved.

Of most interest for me today, however, was how to deal with the basement lighting. With the spiral plan, we had a dedicated outlet designed to light just the spiral stairs. The idea was that from the bottom, or the top, you could switch this on before negotiating the stairs. The exit point from the stairs would be adjacent to further switches allowing you to light the destination room. However, now, especially at the bottom, these switches are in totally the wrong place. Fortunately, I have been able to devise and execute a plan to address this.

There is a pair of switches on the basement wall - one for the wall lights and one for the ceiling lights. Both of these are "double-switched" with a pair next to the door to outside. All switches are fed by cables from above which run through the basement ceiling void. There was enough slack in these cables to pull a loop out in the ceiling void, cut the cables, and use a pair of junction boxes to connect in cables from a new pair of switches. This renders one pair of the basement switches obsolete for this circuit, but available for re-use. However, it is not quite that simple, because all the connections to the lights are made in the switch boxes, so I still needed to feed the switched live to the old switch location so that it could be connected up with all the lights.

It was a complicated intellectual exercise to work out what all the wires did (with 6 wall lights, 2 ceiling lights, the live feed, and double switch feeder cables there are 11 cables coming into this pattress !). It is not helped by the fact that there are two approved methods for wiring up a double-switched circuit. These diagrams, stolen without permission from Wikipedia, illustrate firstly the "Traveller" system :


and the "Alternative" or "California" system :

In case you are interested, the "alternative" system has the advantage that there is a live and a switched-live connection at both switches (so you can, for example, connect in lights at both ends), but the downside is you need an extra core in your cable.

After much experimentation with boolean truth tables on the two switch positions, and measuring the voltages on the various terminals, I was confident I was dealing with a "Traveller". My wiring changes seem to have worked, so I guess I was right in that.

One of the two switches in the basement that has become "spare" as a result of this work I have reused to put in a new ceiling light in a corner, that can provide lighting for a reading chair, table, or even a piano.