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How To Wire Switches in Parallel?

How to Connect Two Switches in Parallel to Control a Single Load?

In previous basic home electrical wiring installation tutorial, we learned how to wire single way switches in series. Today, we will learn how to wire and connect two switches in parallel to control and operate a single light point.

Mostly, this is a preferred method to wire single way switches in parallel as parallel or series-parallel connections are used in common electrical wiring installation these days due to advantages over series connection.

Before we go in details, we will see the basic construction and operating mechanism of single way switch which is shown in fig below:

Construction & Working of one way SPST (Single Pole Single Through) Switch
Construction & Working of one way SPST (Single Pole Single Through) Switch

Below is a simple step by step tutorial with schematic and wiring diagram which shows how to wire single way switches in parallel?

Requirements:

  • Single Way Switches (SPST = Single Pole Single Through) x 2 No
  • Lamp (Light Bulb) x 1 No
  • Short pieces of cables x 5 No

Procedure:

Connect the two single way switches, light bulb in parallel to the power supply as shown in fig below. Keep in mind that one of the switches S1 or S2 must be closed to complete the circuit.

If there are more switches connected in parallel with electrical appliance i.e. light point, one of them must be at ON position to operate the load. However, light bulb won’t go off if you switch OFF one of the switch. In other words, all the switches must be closed (OFF position) to disconnect the load from power supply.

How To Wire Switches in Parallel?
How To Wire Switches in Parallel?

The circuit will complete if one of the switches out of two are at ON position. In other words, If one of the switch are close or at ON position, the light bulb will glow then. This is the same case for other loads as well to control by two (or more) single way switches connected in parallel.

Below are the different positions of single way switches and light point when connected in parallel.

Switches in Parallel Different Positions of Switches & Light Bulb
Switches in Parallel Different Positions of Switches & Light Bulb

To get the switching position in ON condition for light bulb, the above operation is same as the Digital Logic OR Gate truth table which is given below.

Switch 1 Switch 2 Lamp Position
0 = OFF 0 = OFF 0 = OFF
0 = OFF 1 = ON 1 = ON
1 = ON 0 = OFF 1 = OFF
1 = ON 1 = ON 1 = ON

In simple words, there are four switching positions and if both the switches are at OFF position, the light bulb will not glow. On the other hand, if one of the switch is at ON position, the current will flow in the circuit as the circuit behaves like completed circuit, hence bulb will glow. No matter all of other connected switches are at OFF or ON positions.

Good to know:

  • Switches and fuses must be connected through line (Live) wire.
  • Switches connection in parallel is a prefer way to wire home appliances. parallel or series-parallel wiring method is more reliable instead of series wiring.
  • More wires and cables are required in parallel wiring connection.
  • It is a reliable and comfortable method of wiring.

Warning:

  • Electricity is Our Enemy, if you give it a chance to kill you, Remember, they will never miss it. Please read all caution and instruction while doing this tutorial in practical.
  • Disconnect the power source before servicing, repairing or installing electrical equipments.
  • Never try to work on electricity without proper guidance and care.
  • Work with electricity only in presence of those persons who has good knowledge and practical work and experience who know how to deal with electricity.
  • Read all instruction and cautions and follow them strictly.
  • Contact the licensed electrician or the power supply company before practicing any change in electrical wiring connection.
  • The author will not be liable for any losses, injuries, or damages from the display or use of this information or if you try any circuit in wrong format. So please! Be careful because it’s all about electricity and electricity is too dangerous.

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26 comments

  1. This is helpful for those who have no basic knowledge in electrical, your instruction is easy to follow. Pls. keep posting.<br /><br /><a href="http://www.woertz.ch/&quot; rel="nofollow">woertz</a><br />

  2. Thanks admin for this wonderful post, full of ideas about electrical. The post is written in very a good manner and it entails many useful information for me. I appreciated what you have done here. <br /><a href="http://www.electricalserviceteam.com&quot; title="" rel="nofollow">Electrical Services</a><br />

  3. Thanks..

  4. i am unable to get the application of series and parallel lamp switch..

  5. Really i too why one should use this parellel combination manes..<br />

  6. Hi! My old house had a light switch arrangement that still has me curious about its workings! Perhaps you can illuminate us with a schematic and/or explanation!<br /><br />We had a light above the stairs, with a switch upstairs, and a switch downstairs. Either switch, when flipped, no matter whether the light was on or off, would turn the light on if it was off, and off if it was on. Can you

    • Sounds to me like you have incorrect polarity. Using a very basic example, it means you negative and positive are the wrong way around. (Negative to positive and positive to negative). Try looking at your switches and make sure the live goes to live and the negative goes to negative. Hope this helps.

    • What you’re describing is a simple 3 way circuit. Nothing wrong with it at all. It requires a special kind of switch and a “traveler” wire between the two of them to work.

      Note that it is NOT a parallel or series circuit. It is a 3 way circuit.

  7. i need design of my newly construct room with singly phase required connections as below:<br /><br />main panel contain 1 Fan Switch , 3 Bulb Switch 3 different points, at least 4 sockets required on main panel.<br /><br />2nd panel required for my Computer containing 6 sockets with 2 switches.<br /><br />3rd for electrical iron.<br /><br />kindly suggest me the basics of electrical wiring or

  8. I think it only for concept building otherwise no use of this circuit configuration

  9. IN A SINGLE PHASE CONNECTION, CAN U HAVE 2 SWITCHES ON 2 DIFF MCBS POWERING THE SAME BULB.IN A PARALLEL CIRCUIT

  10. what happen if we switch on both switches at a time

  11. what will happen if the two switches are in ON state

  12. Why we use 2 switch’s for a single bulb

  13. it does not happen ….

  14. why we use here 2 spst switch

  15. I have an overhead ceiling mounted light fixture in my hallway. I have a switch on one of the ends of the hall that I use to turn the light on and off with. The other light switch on the other end of the hall does nothing. I would like to have the capability to turn the light on and off using both switches if I need to. Both switches were wired to do that when house was built
    I would also like to turn the light on with one switch and turn it off with the other switch. Any ideas?

    Scott

  16. I have a 3 phase pump mtr powered by an inverter that converts single phase 220 into 3 phase. the 220 to the inverter is controlled by an irrigation timer that sends 24vac to a relay which gives power to the inverter.
    I would like to add a second method for turning on the motor. This would be a pressure sensing circuit that would start the mtr through inverter when water pressure falls below a preset number.
    It could happen that the inverter would be running the pump when the timer clicked on. This would mean two parallel “switches” would both be on. The switches in this case would be two dpst relays each controlled by their separate sensing device (time clock/pressure switch)and separate coil voltage sources. The 220 power source would be the same mains power.
    This seems right to me. Am I missing something?Naturally the hot legs must not cross…or kaboom.

  17. So if one switch is closed, the other is effectively useless?

  18. I can definitely see why you would want to set up a parallel system with AC power and some switches. It seems like such a simple system could could be expanded upon to create a much more intricate service. I can see this functioning to power a something as large as a city grid.

  19. very good explanation

  20. Thank you for this explanation. This is helpful for my use case where i would want to add a smart switch for a bulb but would want the bulb to turn on either with the smart switch or with the physical switch. however, i would turn off only when both are off.

    Could you confirm that this would not have any impact if both the switches are on and ideally the result would be the same as if either one was on.?

  21. where we use switches in parallel and where we can use switches in series and its benefit

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