Single Pole VS Double Pole and How They Work

Single pole and double poles are widely used in many products. Both switches and circuit breakers are available in single pole and double pole versions. This article will help you understand the differences and functions of single pole and double pole in switches and circuit breakers. Welcome to read.

What Is Single Pole and Double Pole?

In electrical engineering, single pole and double pole are commonly used electrical terms. Its manifestations are also diverse.

A single pole switch, SP for short, means that it has only one electrical contact, so it can only control the flow of one circuit, one input and one output. Ordinary ones can be normally open or normally closed, or self-resetting or self-locking, so it can generally only control simple electrical appliances or equipment.

Double pole switch, referred to as DP, means that it has two sets of electrical contacts, which are connected to two independent circuits. It can control the two circuits respectively, and can also behave in a momentary or self-locking state. It is suitable for more complex and flexible circuit control and equipment.

Among small circuit breakers, single pole and double pole miniature circuit breakers are the most common types. They not only protect the small circuit breaker itself, but also the entire circuit against overvoltage, undervoltage and fault current. Single pole miniature circuit breakers can only control one line (live line). The 2-pole miniature circuit breaker is two independent single poles merged together, which can interrupt two circuits at the same time, and can control one live wire and one neutral wire at the same time, with higher safety.

In short, the definitions of single pole and double pole switches and circuit breakers are relatively easy to understand. If you want to know more about unipolar and bipolar, you can search for more related articles to read.

figure1 What Is Single Pole and Double Pole

What’s Difference between Single Pole and Double Pole?

Difference in Voltage

There are many different series of single pole switches and double-pole switches, both divided into direct current and alternating current. However, the voltages of small circuit breakers are quite different, but the current can reach 63A.

The voltage of single pole AC miniature circuit breaker is 120VAC, and the voltage of double pole is 220VAC.

The voltage of 1P DC miniature circuit breaker is 250VDC, and the voltage of 2P is 500VDC.

Difference in Wiring

Single-pole switches are the easiest to wire. If there is current flowing across both ends, the switch will function normally.

There are many double pole switch terminals, up to 6 or 8. The switch overload is connected to two terminals and the common pin is connected to one terminal so that both sets of circuits can be controlled. Then connect the positive and negative poles of the LED according to the usage requirements.

A single pole miniature circuit breaker can only be connected to one wire, with the live wire on top and the neutral wire on the bottom.

The most popular term for a double pole small circuit breaker is the left fire and right neutral wire, which means that the left side is connected to the live wire up and down, and the right side is connected to the neutral wire.

figure2 What’s Difference between Single Pole and Double Pole-Difference in Wiring

Difference in Application

Single pole and double pole switches or circuit breakers have different complexities due to the different circuits they control, so their uses are also different.

Single pole switches are one of the most common electrical components in life. They can be used for simple lighting control, socket current control or simple appliance control, function selection, etc. For example, escalator emergency stop buttons, alarm buttons, etc.

The more complex design of the bipolar switch makes it suitable for more complex environments, and the route of one end can be controlled independently. For example, complex lighting systems, multi-purpose socket combinations, more complex electrical equipment and circuit controls, and pressure switches are all bipolar switches.

Single pole circuit breakers are suitable for small electrical equipment whose voltage requirements are usually not too high, such as main switches for small lighting systems in home power boxes, DC battery packs, small photovoltaic applications, etc.

The double-pole circuit breaker has a higher rated voltage and can be applied to mechanical equipment with large power loads such as central air conditioners.

figure3 What’s Difference between Single Pole and Double Pole-Difference in Application

All in all, in addition to these differences, there may be other differences. You can try to search for more keywords.

FAQ

What is the price difference between single pole and double pole?

Because double pole structures are more complex than single poler structures, double pole structures are generally less expensive than single pole structures.

How to tell if your switch is unipolar or bipolar?

You can check through the terminals. Single pole switches have two terminals, and bipolar switches have six or eight terminals.

Are double pole switches more difficult to install than single pole switches?

Bipolar switches have more terminals than single-pole switches, so installation is a little more complicated but not difficult. But whether it is a simple or complex installation, it must be installed by professionals.

Is there a difference in size between single pole and double pole circuit breakers?

Yes, single pole miniature circuit breakers have a module width of 12.5mm, double pole modules are twice as wide and have four terminals.

What are the advantages of single pole and double pole?

Affordable price, easy installation, wide application range, easy operation and strong adaptability.

How to tell if unipolar or bipolar is broken?

Usually measured with an electric pen or multimeter.

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