Difference Between One-Way Electrical Switches And Two Way Electrical Switches

Comparisons, Knowledgebase

Last Updated on November 25, 2022 by mdmtool

In any electrical circuit, there must be a switch to open or close the course and allow or prevent the flow of current. The most basic type of switch is the single-pole, single-throw (SPST) switch, which consists of two terminals that can be connected or disconnected. These switches are used in circuits where only one controls the current flow.

What Is A One-Way Switch?

what is one-way switch

A one-way switch only has two terminals, which can be either opened or closed. This switch is used in circuits where just one switch controls the current flow.

How Does A One-Way Switch Work?

A one-way switch either allows or prevents current flow through its terminals. When the button is in the open position, current can flow freely through the circuit. When the switch is closed, the current is cut off and cannot flow through the circuit.

What Is A Two-Way Switch?

what is two-way Switch

A two-way switch has two terminals but can have either an open or closed position. This switch is used in circuits where two switches control the current flow. 

Difference Between One-Way Switch And Two-Way Switch

one-way switch

Principle Of Work: The basic principle on which the one-way and two-way switch work is the same. In both these switches, the current flowing in the circuit can be controlled by opening or closing the switch. The only difference lies in the number of positions these switches can assume.

Function: A one-way switch can assume only two positions – open and close. In the open position, it disconnects the circuit, and in the closed position, it completes the course. On the other hand, a two-way switch can assume three positions – open, secure, and intermediate. In the middle position, neither of the circuits is completed.

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Number Of Terminals: A one-way switch has only two terminals, while a two-way switch has three terminals.

Position Of Switch: A one-way switch is usually placed in a circuit at the end. It is used to control the light by switching it ON or OFF. A two-way switch is generally placed in the middle of the circuit. It controls the light from any of the two places.

Termed: A one-way switch is a single pole switch or a make-and-break switch. A two-way switch is a double pole switch or a transfer switch.

Circuit Complexity: A one-way switch’s circuit is more straightforward than a two-way switch.

Thus, we can say that a one-way switch is an elementary switch, while a two-way switch is a more complex form of control.

Installation And Time: The installation process of a one-way switch is quicker as compared to the installation process of a two-way switch. A one-way switch requires only two wires, while a two-way switch requires three wires.

Type Of Current: One-way switches can be used for both AC and DC, while two-way switches can be used for DC only.

The Direction Of Current: One-way switches allow the current to flow in only one direction, while two-way switches allow the current to flow in both directions.

The Number Of Contacts: One-way switches have one set of contacts, while two-way switches have two sets of contacts.

Operation: One-way switches are manually operated, while two-way switches are automatically handled.

Cost: The cost of a one-way switch is less as compared to the price of a two-way switch. This is because a one-way switch contains fewer components than a two-way switch.

Applications: One-way switches are used in those circuits where we need to control the light with just one controller. For example, we use a one-way button to control the ceiling light in a room. Two-way switches are used in those circuits where we need to control the light with two switches located at different places. For example, in a stairwell, we use a two-way switch to control the light from both the top and bottom of the stairs.

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These were the significant differences between one-way switches and two-way switches.

two-way switch

Types Of One-Way Switch

There are two types of a one-way switches –

  • SPST (Single Pole, Single Throw)
  • and
  • DPST (Double Pole Single Throw)

Types Of Two-Way Switch

There are two types of a two-way switch –

  • SPDT (Single Pole Double Throw)
  • and
  • DPDT (Double Pole Double Throw)

Precautions For Safe Use Of Electrical Switches

Using electrical switches is generally safe if the following precautions are taken:

  • Use nationally recognized testing laboratory switches
  • Do not use improper switch sizes for the circuit amperage and voltage.
  • Do not use switches that are damaged or have missing parts.
  • Do not operate switches with wet hands.
  • Do not use switches that are hot to the touch.
  • Always turn off the power to the circuit before working on it.
  • Follow all local building codes and ordinances when wiring switches.
  • Hire a qualified electrician if you are unsure how to wire a switch correctly.



How Does A Light Work With Two Switches?

In a two-switch light circuit, each switch controls one of the lights in the circuit. The two buttons are wired so that they control the lights independently.

Can A One-Way Switch Be Used To Control The Light From Two Different Places?

No, a one-way switch can only be used to control the light from one place.

How Do You Wire A 2-Way Switch?

To wire a 2-way switch, you will need to start with the power supply, connect the wires to the 2-way switch, and ultimately secure the cables to the light. You must understand which wires go where for the circuit to work correctly.


Each switch has advantages and disadvantages, so choosing a suitable controller for the job is essential. One-way switches are typically used for simple circuits than while two-way switches. Be sure to consult with an electrician before making any changes to your electrical system.

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