SOLUTION

Staircase wiring is commonly used for staircase and corridor lighting. Normally, only a single light lamp is provided in a staircase which is controlled by either of the two switches – one installed at the top and other at the bottom. Similar is the situation in a bathroom common to two rooms The light lamp in the bathroom can be controlled by the switches installed in the two rooms.

Two-way switches have a central terminal. The central terminal of the first switch is connected to the lower position of the second switch, whereas the central terminal of the second is connected to the upper terminal of the first. We can connect the terminal in reverse fashion also i.e Central terminal of the first switch is connected to the upper position of the second switch, whereas the central terminal of the second is connected to the lower terminal of the first. The figure shows a diagram of two-way switching, that is control of light from two different switches (staircase lighting). When the phase is completed the Lamp start to glow.

Suppose you are at the top of the staircase and the light is in switched off condition, you can switch the light on as you go down, then switch it off as you leave.