Two Way Light Switch

Two Way Light Switch Wiring


Have you ever wonder how a lamp that is used to light up the stairs of a building is connected to the two switches that controls it from either end? These two way switches have a single pole double throw (SPDT) configuration. Each has a common terminal (COM) with a pole that can be switched between position L1 or L2. The two way light switch wiring can be implemented by using 2 different methods. Both of the methods used are described below.



The first method as shown in the figure above have the COM, L1 and L2 of both the SPDT switches connected together. For incandescent lamp, the recommended wire gauge used is AWG #18. The LIVE AC Source is connected to L1 of SW1 and one side of the load is connected to L2 of SW2. The other side of the load is then connected to NEUTRAL of the AC Source. With this configuration, the lamp will be turned ON when one switch is at ON position and the other is at OFF position. If both switches are in the same position, the lamp will be OFF.