How does a Two Way Switch Work - Wiring Connection and Demonstration

electronics

ByPankaj Khatri 8

How to connect a 2-way switch

One of the simple yet interesting connection diagrams that young engineers learn in their lab is the staircase lighting connection set-up. Perhaps most of us might have already used it without paying much attention to how it works. Staircase lighting at home or at any other place for that matter is normally done with something called a two way switch. Now, there are many different types of switch in the market, and few of them directly be used for two way connection without any special two way wiring connections.  But in this tutorial, we will show you how to make 2-way switch wiring with normal household switches. A 2-way switching connection means you can control electrical equipment like bulb by two switches placed at different places, generally used in the staircase. Two way switch can be operated from any of the switch independently, means whatever be the position of other switch(ON/OFF), you can control the light with other switch.

There are two methods of making 2-way switching connection one is 2-wire control and another is 3-wire control. We have explained both the methods below and both the methods are demonstrated in the Video given at the end of this article.

 

Required Components for Two Way Switch Connection 

  • Two 2-way switches
  • Bulb
  • AC supply
  • Connecting wires

 

2-way Switch Wiring  using Two-wire control

2 way switching by 2 wire method

This is the first method to make a 2-way switching connection, this is the old method. If you are going to install a new one then go for three wire control methods.

 

As you see in the 2 way switch diagram below, you will find that the phase/live is connected with the common of the first 2-way switch. PIN1 & PIN2 of the first switch are connected with the PIN1 & PIN2 of the second switch respectively. One end of the bulb is connected with the Common Terminal of the second switch and another end of the Bulb is connected with the Neutral line of the AC power supply.

Note: In the 2-wire control method when switches are in an opposite state the light will be in OFF state as shown in the circuit below:

2 way switching by 2 wire method

 

The condition of getting Output in ON condition is the same as the Ex-nor gate truth table which is given below:

Switch 1

Switch 2

Lamp state

0

0

1

0

1

0

1

0

0

1

1

1

Where, 0 represents the OFF condition and 1 represents the ON condition.

 

How to Connect 2-way Switch Wiring using Three-wire control

2-way-switching-by-3-wire-method

This is the new method to make a 2-way switch connection and it is slightly different from the two-wire control method. This method is commonly used nowadays as it is efficient than the Two-Wire control system.

As you can see in the Schematic Diagram of 2 way switch circuit below, the common of both the switches are short-circuited. PIN1 of both the switches are connected with the phase or live wire and PIN2 of both the switches are connected with the one end of the lamp. The other end of the Lamp is connected with the Neutral line of AC power supply.

Note: In the 3-wire control method when switches are in the same state the light will be in OFF state as shown in the circuit below:

2-way light switch circuit diagram using 3-wire method

The condition of getting Output in ON condition is the same as the Ex-or gate truth table which is given below:

Switch 1

Switch 2

Lamp state

0

0

0

0

1

1

1

0

1

1

1

0

Where 0 represents the OFF condition and 1 represents the ON condition.

 

Applications of Two Way Switch:

  • Mostly in the stair case.
  • Erroneous tripping of safety/circuit protection equipment.
  • A big room having two entry/exit gate.
  • To control any AC appliances like fan or light from two places like entry and exit.

 

Video

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Comments

  • Abhrodeep Chanda's picture
    Abhrodeep Chanda
    Nov 23, 2017

    It's a age old logic but still a mesmerizing thing to people who doesn't belong to this domain. Thanks for explaining it so clearly.

  • RBenton Jacks's picture
    RBenton Jacks
    Nov 28, 2017

    In the electrician's trade, the two switch location load control is termed a '3-way' system. The wiring schematic conforming to the adopted International Code Council requires a different physical configuration for safety compliance than what is demonstrated in this article.

  • anees yarana's picture
    anees yarana
    Dec 03, 2017

    Thankyou so much.
    .I like it

  • Pacheco's picture
    Pacheco
    Jan 08, 2018

    Thank you for this acticle. You solved a problem for me.

  • Frank's picture
    Frank
    Apr 08, 2018

    Does anyone know how to do this with an led mech like the clipsal 30PBL? I'd like the mech led off when that switch is powering the light.

  • jack's picture
    jack
    May 08, 2018

    nice tutorial of new way of two way two place light control connecting but there is one isuue compared to old way - one additional wire leading in parallel to light. this is redundancy every one want to avoid

  • kurt's picture
    kurt
    Jul 09, 2018

    It is a good explaination thanks

  • John King's picture
    John King
    Jun 19, 2021

    The three wire versions only virtue is having both switches the same way up.

    With the two wire version you just turn one switch through 180 degrees and it amounts to the same!

     

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