Electric switches can either be single or double poles. A single pole switch has only one set of contacts inside. A double pole switch on the other hand has two sets of contacts. Double pole switches also incorporate double pole single throw switches.
So what is a double pole single-throw switch? And more importantly where is this type of switch used?
What is a Double Pole Single Throw Switch
A double pole single through switch aka DPST is defined as a switch that has two inputs and outputs. In this regard, every input in the switch has an output that corresponds to it. Furthermore, each of the switch’s terminals can either be in the on or off positions.
The benefit of this type of switch is that it is versatile and capable of operating two outputs in a circuit. The switch will depend on the design of the circuit and what it is intended to do.
How to wire double pole single throw switch
Connect the Two Hot Wires
With a double pole single throw switch, you have two hot wires from the power source going to the switch. This will typically be a red and a black wire with green ground. There is also a white neutral wire.
Connect the two hot wires to the input terminals of the switch. The ground wire should be connected to the ground terminal of the switch. For a 240v connection, there is no need for the neutral.
Connect Corresponding Wires
Next, connect the two hot wires from the appliance to the output terminals of the switch. The ground wire should be connected to the appliance as well. Thus when you turn on the switch, you power the appliance by simultaneously powering the two hot connections.
How Does a Double Pole Single Throw Switch Work
A double pole single throw switch has two sets of inputs and outputs, thus four in total. When the switch is turned on, both wires are set to the closed position allowing electric current to flow through to the appliance.
On the other hand, when the switch is turned off, the wires are set to an open position restricting the flow of electric current to the appliance.
Double pole single throw switch symbol
The double pole single-throw switch is represented by a diagram of two wire connections parallel to each other. The two wires are either closed or open.
How Does a Double Pole Single Throw Switch Look like
This type of switch has four sets of terminals, two inputs, and two outputs. There is also a ground terminal for the ground wire. These types of switches come in many variants but the notable feature is the four terminals.
What Are The Uses of Double Pole Single Throw Switch
- Used in scenarios where you want to fully isolate power, this can be when dealing with two active AC inputs, with a 2 phase supply
- Is also used where you need to switch two separate power sources at the same time.
- Can also be used to power appliances that require heavy loads such as dryers, water heaters, and washing machines.
Differences Between a Single and Double Pole switch
A single pole switch has one input and one output. This is the kind of switch you would see in standard electrical appliances such as lights. In this set up the switch controls one circuit and one wire, and there is only one connection made.
There is also a single-pole double-throw switch. This type of switch has one input and two outputs. In this regard, it consists of a three-way circuit and is used to turn on/off an appliance from different locations. For example, you can have lights that can be turned on/off from two different places.
A Double pole switch on the other hand has two terminals. In this regard, you have two switches located side by side. There is one toggle meaning two different circuits can be controlled from one place.
This type of switch is used to turn on/off two different circuits and consists of four terminals. There are two inputs and outputs. These types of switches are mainly used to regulate 240 v power appliances, where the two voltages must be on. When the switch is on, current flows to the two circuits and it stops when it is off.
Thus the main difference between these two types of switches is the number of terminals present and the number of circuits they control. A double pole switch controls two separate circuits, while a single pole switch controls only one.
DPST Wiring Precautions
- When working with a double pole single-throw switch, it is important to first switch off power in the main circuit breaker.
- If you are not sure about the correct wiring diagrams contact an electrician to do the installation
- Use the proper voltage and rating switch with the right gauge wire based on the switch’s load rating
- Neutral wires are not necessary for 240v wiring, and the neutral wire should not be connected to the switch.
Faqs About double pole single throw switch
Conclusion
When it comes to switches double pole switches are recommended for large appliances as they are safer than single pole switches. Double pole single throw switches can be a good option for large appliances, and it is important to know what they are and how they work.