Instructions for connecting 3 No's of 3way switches(4 terminal switches ) for controlling a single light .

Above 3 switches are installed at 3 different locations in a building for controlling a single lamp.All the 3 switches are having 4 terminals but in 2 of the switches one top & one bottom terminals are interconnecte internally in the switch.As such in 2 switches ,only 3 wires(say red,black,red) get connected ,while as in third switch 4 wires(say red-black in the top 2 screws & red -black wires in the bottom terminals are connected).The neutral wire is connected to the lamp directly while the live wire/phase is connected to one of the 2 switches with 3 wires.This practice is in vogue in the USA.

A connection diagram showing the three switches connecting various colored wires with the lamp may please b mailed to me for doing the project myself.

3 Answers

  • Anonymous
    1 decade ago
    Best Answer

    If you are installing 3 swithces to control one light bulb, You need 2 three way switches, and one 4 way switch. The three way switches have 3 terminal, and the 4 way switch has 4 terminals. Wires must be connect to all terminals. For one of the three way switches, you need to connect that to a power source, and the other three way switch you need to connect it to the light bulb. The 4 way switch will be in the middle between the two three ways, and two of the terminals from the three ways will land on two of terminals from the 4 way. Each three way will land on separate terminals at the 4 way.

    Look at the wiring diagram on the box.

    Draw it out on paper. You connect the commons on the three way to the 4 way.

  • EE68PE
    Lv 6
    1 decade ago

    Look at:

    What is usually called a 3-way switch is a 3-terminal switch. What is usually called a 4-way switch is a 4-terminal switch. As shown in the Wikipedia article, controlling a light from 3 or more locations is usually done with two 3-way switches and one or more 4-way switches. However, it is possible to use only 4-way switches and leave one terminal unconnected on two of the switches.

    It appears to me that the Yahoo Answers email system does not provide for sending attachments.

    Added sketch link:

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