How To Connect Two Way Switch? Easy Two Way Switch Diagram

A light switch is a modest device thanks to which everyday life in one’s house gets far easier. While standard interiors use singular switches, places such as stairs might get more complicated. For this, a special two way switch circuit is needed, which allows to control the light from two spots. How to connect a two way switch? It is not that difficult - just take a look at a two way switch diagram and use it at your own place.

A simple two way switch diagram
A simple two way switch diagram

Two way light switch - what are its features?

There is probably not too many people who are not electricians and pay attention to devices such as light switches. It is enough that they serve their function - that is, turn the light on and off. These devices, however, concern exactly the matter of functionality - there are many types of them, and choosing the right one might not be that obvious for a layman.

Specialists classify light switches in accordance to several criterions. The most common types are:

  • Surface and flush-mounted light switches - the differentiation concerns the installation method.
  • Single and double-pole switches - the first ones control a single light source, whereas the latter can control two light bulbs at the same time.
  • Multipole switches - they control more light sources and usually have two or more buttons.
  • Automatic switches - they switch off the light automatically after a given time.

Judging by aesthetics, one can also distinguish light switches according to the type of buttons. Manufacturers offer traditional switches with a mechanical button. Touch light switches are gaining popularity. They have a smooth panel with a sensor which reacts to touch.

Two way light switch - what are its features?

Two way and three way light switch

Two way light switches are a special type of devices. They allow to control one light source from two different locations. It’s a particularly useful solution on staircases, so that one does not have to come back up or down to turn the light off.

For the same reason, the two way switch diagram is used in long corridors.

If more than two switches are needed for light control, one should use a three way light switch. Such circuit involves two external switches and one three way light switch between them.

How to connect a two way switch?

Connecting any switch - a two way switch as well - is not a difficult task, although one needs to follow certain rules. Of course, the basic issue to remember when connecting a light switch is cutting the electricity off. Apart from this, one has to understand how a light switch works.

Light switch - general principle of operation

Generally speaking, to connect a light switch, one needs several elements. They are:

  • Phase wire - it’s usually the black or the brown wire, although it might also be marked with another color - except from blue and yellow-green. It is marked by letter L on the diagrams presented below.
  • Neutral wire (N) - it’s blue.
  • Earth conductor (PE) - it’s a grounded wire, marked with yellow-green insulation.
  • Wires connecting the switches (P1, P2…)
  • Light source.
  • One or several switches.

Each switch - one or multiple way, operates based on similar principle. To turn on the light, one has to move the switch, that is - close the electric circuit. Analogically, moving the switch back off cuts the circuit and the electricity stops flowing - the light goes off.

To connect the simplest one way light switch, one needs to connect wires between the switch and the light bulb. See the diagram for such a circuit below:

A light switch - general principle of operation

Under no circumstance mix the wires - for instance phase with the neutral line. It would pose a threat during changing a light bulb - even when the light is turned off!

Two way switch - diagram

Connecting a two way switch circuit is a little bit more complicated, as it uses two switches. So - how to connect a two way switch?

A two way switch diagram is more elaborate. In this case, the phase wire is connected with one of the two way switches, and the light source - to the other. Neutral wire and earth conductor are lead to the light source independently. The two switches should be connected with each other with additional wires.

See the two way switch diagram below:

Two way switch - diagram

How to connect a three way light switch?

As already mentioned, it is possible to wire more than only two light switches for the same light source. To do this, one needs to use a three way light switch. The scheme of such connection is not much different from the two way switch diagram - there is a third switch between the two external ones. The number of intermediate switches is unlimited, and it can be adjusted as needed. Thanks to this one will be able to turn off the staircase light while being in another room.

See the three way light switch diagram presented below:

How to connect a three way light switch?

Connecting a two way or a three way switch is not as difficult as it might seem. If you have the right switch diagram, you can easily do it yourself.


Mateusz Knapik
Author: Mateusz Knapik Sales and Customer Support Specialist at Instalguru

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