The master switch is a lighted rocker switch that will be on the left wall behind the ladder. It will shut off the power to the transformer, shutting down all of the lighting.
I drilled holes for the mounting screws and tapped in plastic inserts. Then I cut a rectangle out of the outer layer of the wall.
Then I routed a cavity 1/2 inch deep into the second layer for clearance on the back of the switch.
John Blake Online 