What is Two Way Switch Wiring : Circuit Diagram & Its Working

A switch is an electrical device that controls the flow of current in a circuit. Every electronic and electrical application uses at least one switch to perform on and off operation of the device. The switches are further classified into two types they are electrical switches and mechanical switches. The one-way (single-pole), two-way (double-pole) are the two types of an electrical switch. The two-way switch is used to on/off the light, fan from two different locations. This article discusses the two-way switch wiring function, working, and circuit diagram.

What is a Two-way Switch?

The two way (double-pole) switch is used to ON and OFF the light from two different locations and the switch is mostly used in the case of stairs, in rooms that have two entries. This type of switch is generally used in some home wiring systems and industrial applications.


Two Way Switch Wiring

The COM, L1, and L2 are the three terminals of the two-way switch. The L1 terminals of both the switches are connected to phase, and L2 terminals of both the switches connected to one end of the bulb terminal and the other end of the bulb terminal are connected to neutral of the AC supply. The three-wire two-way switch wiring diagram is shown in the below figure.

Three Wire Two Way Switch Wiring
Three Wire Two Way Switch Wiring

The configuration of the three-wire two-way switch wiring is similar to the EX-OR gate in terms of digital electronics. 

S.NO Switch 1    COM Switch 2 COM Light 

1 

L1L1OFF 

2 

L1L2ON 
3 L2L1

ON 

4 L2L2

OFF 

The light is OFF when COM terminals of both the switches are connected with L1 or L2 terminals. The light is ON when the first switch COM terminal is connected with the L1 terminal and the second switch COM terminal is connected with the L2 terminal. Similarly, the light is ON when the first switch COM terminal is connected with the L2 terminal and the second switch COM terminal is connected with the L1 terminal. This is the function of two way switch wiring.

The two-way switch front and the back view is shown in the below figure. 

PCBWay

Two Way Switch Front and Back View
Two Way Switch Front and Back View

Alternative Method of Two Way Switch Wiring

The two-wire control two-way switch mostly will find in some of the industrial settings and old homes. The first switch COM terminal connected to phase and second switch COM terminal is connected to one end of the bulb and the other end of the bulb is connected to neutral AC supply. The L1 and L2 terminals of both the switches are connected together. The two-wire control two-way switch is shown in the below figure.

Two-Wire Control Two Way Switch
Two-Wire Control Two Way Switch

This configuration is similar to the EX-NOR gate in digital electronics. 

S.NO Switch 1 COM Switch 2 COM Light 

1 

L1L1ON 

2 

L1L2OFF 

3 

L2L1

OFF 

4 L2L2

ON 

The light is ON when the COM terminal of both the switches is connected with L1 or L2 terminals. The light is OFF when the first switch COM terminal is connected with the L1 terminal and the second switch COM terminal is connected with the L2 terminal. Similarly, the light is OFF when the first switch COM terminal is connected with the L2 terminal and the second switch COM terminal is connected with the L1 terminal.

In the above schematic diagram, the status of the light is off, but the light turns on when the switch is toggled. 

One Gang Two Way Switch Wiring

The one gang two-way switch is used when two switches control the single bulb.  The one gang two switch diagrams are shown below.

One Gang Two Way Switch
One Gang Two Way Switch

Fig (a) is the two way light switch mechanism, fig (b) is the single gang switch face and fig (c) is the single gang two way light switch. The switch is on when the COM terminal and L1 terminals are connected and the switch is off when the COM and L2 terminals are connected. 

Multiway Switching

There are three types of circuits they are open circuit, close circuit, and short circuit. When the switch is in off position then the circuit is said to be open circuit. The terminologies related to switches are different between the US and the UK. In the UK they refer to two-way switch and cross over switch. In the US they refer to a three-way switch and four-way switch. The US terminology used in this explanation. Let start with the basic idea of the light switch in an electric circuit. The basic circuits of on and off the light is shown in the below figure. 

Basic Circuits of ON and OFF the Light
Basic Circuits of ON and OFF the Light

Let say you have two different entrances to a room. Now you need different kinds of switches called three-way switches probably because they have three contacts. In between the two switches, the two lines are called travelers. So now you can on and off the light by the first switch and the same for the second switch or you can on the light with the first switch and off with the second switch.  

The four-way switch is commonly used to control the light from more than two different places and it is simply a cross switch or cross over switch which has two states. This switch is installed between the two other switches and toggles the active traveler. This means any switch contains the light on or off, with this concept you can add an endless four-way switch into the circuit. The multiway switching is shown in the below figure. 

Multiway Switching
Multiway Switching

Two Way Switches

Some of the two-way switches with cost are shown in the below table 

S.NO 

Two Way Switches Brand Current Voltage 

Cost 

1 

White Legrand Britzy LEGRAND 16 Amp 230 V Rs 146/Piece 

2 

Maddox white modular two-way switch MADDOX 16 Amp  240 V  Rs 29/Piece  

3 

Affonso modular switch AFFONSO 10 Amp  240 V  Rs 18/Piece  

4 

Schneider two way modular switch SCHNEIDER 10Amp  220 – 240 V  Rs 17/Piece  

5 

Arcitech 2 way electrical switch ARCITECH 6 Amp  220 V  Rs 63/Piece  

Precautions for Safe Use

Some of the precautions for switches is shown below

  • Make sure to turn off the AC power supply before wiring, mounting and dismounting a switch, otherwise switch may burn
  • Don’t perform wiring when the power is supplied to a switch, otherwise, an electric shock may occur
  • Don’t use switches in the atmosphere which contains combustible or explosive gases

In this article what is two-way switch wiring, one gang two-way switch wiring, multiway switching with the circuit diagrams, an alternative method of the two-way switch, and basic circuits of on and off the light are discussed. Here is a question for you, how does a Double Pole Double Throw switch works?

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