Automatic Transfer Switch Diagram And Operation Procedure

Transfer Switch

What Is Transfer Automatic Transfer Switch and How Does Work?

 Transfer Switch is nothing but an electrical device that allows to transfer electrical flow safely from multiple Utility-Stanby Power Transfer Switchsource to load. On the other way the load can trans-receive electrical energy from multiple source safely.

To prevent the power outage from main utility power supply a transfer switch can take power from alternate utility source or standby generator source or even emergency power backup source.

Transfer Switch can operate automatically as soon as failure the main source or after a certain period of time to reinstate the main source. This type of transfer switch is known as Auto Transfer Switch or in short ATS.

Other Transfer Switch is known as manual transfer switch which is operates manually.When the utility power goes out, its simply need to plugin the alternate source into transfer switch to start it up, and flip the transfer switch from the main source position to the alternate source position.

In very basic, transfer switches are two types-
  1. Auto Transfer Switch, &
  2. Manual Transfer Switch.
In common transfer switch is known as ATS or Change Over Switch.


Why Transfer Switch Is Needed
You can use your generator power in your home to feed your TV, Refrigerator  or Internet while utility power or main power is outage, just change over the switch from utility to generator. Life becomes easier and faster;

In industry, each minute is seeking for production. To continue production chain break-less, uninterrupted power supply is very essential, and ATS takes the vital rule in this case;
In data processing or data storage center, continuous power supply is essential to backup the important data. ATS plays main rules to keep power supply alive;

In signal controlling station like airport, metro, fire-department, defiance etc. need trouble less power supply to transfer important information; ATS needs to ensure uninterrupted power supply;

In hospital, so many life supporting equipment are operating and can not be off for a single moment. ATS works to continue the life supporting power supply.

Wiring Diagram for Change Over Switch or Transfer Switch


Transfer Switch Wiring Diagram
In schematic line diagram shown how to wire the Transfer Switch with main service disconnect switch for utility power source and generator power source along with your load disconnecting circuit breakers.

Here, Line-1 & Line-2, neutral and grounding connection is shown perfectly that will help to work with your own job.

This is not followed any specific regulation, this demonstrated just for improve your basic knowledge. Before perform your practical job must follow the local safety rules and regulations. 

If it is helpful, share your friends, and to improve this article delivery your valuable comments below.


  1. Picture shows someone brand is not for any advertising. This is simple photograph for demonstration the basic setup for an ATS or Automatic Transfer Switch for connection with a grid power source and generator source or standby source.

  2. ABB offers a wide selection of automatic transfer switches (ATS), from 160 to 1600 Amperes in range. They have the features and functionality that makes them suitable for diverse applications: industrial plants, docks, airports and data centers.

  3. Thanks , I have recently been looking for info approximately this subject
    for a while and yours is the best I have discovered till now.
    However, what in regards to the conclusion? Are you sure concerning the supply?


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