Automatic changeover switch for generator connection by Tiamiyu Abdulbazeet Olawale. Automatic changeover switch for single phase generator, automatic changeover switch, changeover switch, how to connect automatic changeover switch using relay, how to connect automatic changeover switch.

Are you looking for a way to connect the automatic changeover switch for the generator? If that is the case, you are in the right place. Here, we will explain everything you need to know about the connection!


Before we start, I’d like to explain some terms.

So, what is a changeover switch and how does it function?

What is a changeover switch: It is a switch that switches control between two electricity sources.

When a power outage occurs, a changeover switch is used to transfer electricity from the commercial power system to a local generator. They link directly to the generator, commercial power source or line, and the house, and are sometimes known as “transfer switches.” When a power outage occurs, the homeowner or company owner can use a changeover switch to switch to the generator.

Despite the fact that there are dozens of distinct types of changeover switches, most of them fall into one of two categories: automatic or manual. 

What is an automatic changeover switch: From the word “Auto” which means “self” and from the word “Automatic” which means “(of a device or process) working by itself with little or no direct human control.”

So, an automatic changeover switch is a switch that changes itself without direct human control. It switches the control between two electricity sources.

During a power outage, an automatic changeover switch switches the electricity to the home, avoiding the need to manually switch. 

What is a manual changeover switch: It, on the other hand, requires the homeowner to flip a switch to switch the power demand from the commercial grid to the generator.


  1. Electric pole
  2. Single pole MCB
  3. Energy meter
  4. 2-pole MCB
  5. Magnetic contactor
  6. 220V pin relay
  7. Generator (single phase)


  1. Electric pole: An electric pole is a column or post that supports overhead electricity lines and other public services including electrical cable, fiber optic cable, and related equipment like transformers and street lights.
  1. Single pole MCB: (MCB – Miniature Circuit Breaker) A single pole MCB is a circuit breaker that can only switch the PHASE wire. It has two wire connections: one for the incoming wire and one for the outgoing wire. Switching between these two places is handled by the MCB.
  1. Energy meter: An electricity meter, also known as an electric meter, an electric meter, an electrical meter, an energy meter, or a kilowatt-hour meter, is a device that monitors the quantity of electric energy consumed by a home, a business, or an electrically powered item.
Energy meter
  1. 2-pole MCB: (MCB – Miniature Circuit Breaker) It’s a circuit breaker that allows you to switch between PHASE and NEUTRAL wires. At the top, there are two connecting points, and at the bottom, there are two. The points are used to link the phase and neutral wires in the incoming/outgoing phase.
2-pole MCB
  1. Magnetic contactor: Magnetic contactors are used in electric motors to balance the change in frequency or state of the motor, which is referred to as the motor switching from ON to OFF state.
Magnetic contactor
  1. 220V 5 pin relay: 5 pin relays provide 2 pins (85 & 86) to control the coil and 3 pins (30, 87 & 87A) which switch power between two circuits. They have both normally open and normally closed connection pins.
220V 5 pin relay
  1. Generator: An electric generator is a device that converts mechanical energy obtained from an external source into electrical energy as the output.


The image below clearly shows how to connect automatic changeover switches easily using a 220V 5 pin relay. 



  1. NO – Normally Open
  2. NC – Normally Close
  3. N – Neutral wire
  4. L – Live wire
  5. Throughout the diagram, blue lines indicate Live wire while black lines indicate Neutral wire.

You should know this about automatic changeover switches!

Relay works on Normally Open when the coil inside is energized and Normally Close when the coil inside is not energized.


An automatic changeover switch can improve your business’s security and productivity. You’ll obtain the following benefits if you choose the proper switch for your needs:

  • Power reliability: If you lose power for any reason, your business will come to a complete halt. While a generator may help reduce this, you’ll have to manually connect your generator to the operations you want to resume if you don’t have a transfer switch. This task not only takes a long time and results in downtime, but it also limits the capabilities of your generator.
  • Safety: Handling any source of power can have negative consequences. An unexpected outage might hurt employees, and operating a manual generator hookup can be dangerous—especially in the dark! An automatic changeover switch handles all of your needs all on its own, removing the dangers associated with an outage entirely.
  • Simplified operations: Specific processes are specified to be automatically powered when your automatic changeover switch is installed. Everything from your lighting to your HVAC systems, industrial equipment, and even refrigerators might be affected. This method greatly simplifies power restoration and enhances the performance of your generator.
  • Ideal for less accessible generators: Operating a manual switch may not be inconvenient if you operate a small business and the generator is housed in an easily accessible utility room. Having to access manual models in the middle of an outage is cumbersome and potentially dangerous for institutions whose generators are located in upper places that require ladders, catwalks, and special keys to access.

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Businesses That Benefit the Most from an Automatic changeover Switch

An automatic changeover switch can assist any organization, no matter how big or small. And our staff promises that the investment will be well worth it. When you think of an automatic changeover switch, though, there are a few companies that immediately to mind:

  • Government buildings
  • Commercial structures
  • Factories
  • Hospitals and medical buildings
  • Companies
  • Warehouses
  • Malls
  • Restaurants
  • Schools e.t.c

If you want to know more about house wiring connections, click here!

Of course, your opinion is always welcome! If you have any suggestion(s) or question(s) about the connection of the automatic changeover switch explained above, kindly use the comment box!

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About Teezab 1349 Articles
His Name is Tiamiyu Abdulbazeet Olawale. He is a student at the University of Ilorin studying Electrical and Electronics Engineering. He likes to give the latest updates about Nigeria and international institutions as he aims at helping people to lay their hands on the right information.

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