Two way switch

If you stay in single story house,Double story house or in a bungalow, you probably know this two way switch. This switch is commonly used in where houses have stairs. You can't go up and down on stair to switch on or off  the light. So this two way switch are used. So you can turn on or off either at upstairs or downstairs. Easy right. Now lets look about two way switch.

Two way switch have three connection. (COM) common, L1 and L2. For this switch COM connection is the main. The L1 and L2 can be connect to each other or vise versa.

To wired this switch, two 2 way switch are used to wired for stairs as the picture shown below.

In this picture above shown the COM in S1 (switch 1) is connected to MCB at distribution board. Another COM in S2 (switch 2) is connect to the Light bulb. The L1 and L2 are both switches connected each other or vise versa. In Off stage the S1and S2 are off. or both switch are On, So the light will won't light up as the picture below shown.

In ON stage the S1 are off  and S2 are On. So the light will be on. For example, S1 at downstairs and S2 are at upstairs. If you ON the S1 at downstairs , the bulb will light up. In case you want to turn the light off, you can turn On the S2 or turn Off S1.

The symbol for this two way switch is a round and a F at the top of round.

Now you are know how to use two way switch and lighting up the stairs problem are solved