Attari Tech

If you are installing a stand by generator in order to have some electrical power to your home in the event of a utility power outage, it is important that you understand how to properly install a transfer switch.

The transfer switch is the device that transfers the power from the utilities power to the standby generators power, as shown in Figure1.

There are two methods to perform the transfer:

• Manual

• Automatic

In each case, manual or automatic transfer the circuitry is the same. In the case of the manual transfer switch, it requires that someone recognizes that the utility power has failed and must intervene to start the generator and then transfer the desired circuits to the generators power output. A manual transfer switch does not operate if there is no one at home.

In the case of an automatic transfer switch (ATS), the switch has the intelligence to sense when the utility is no longer delivering power and automatically starting the generator and then transferring the circuits to the generator. The automatic transfer switch also recognizes when the utility power is back online, transfers the circuits back to the utility and turns the generator off.

A basic home electrical service looks like this (grounding circuits and wires have been left out in order to make the drawings less cluttered):

The meter is fed from the utility via an overhead or underground conduit as shown in Figure 2. The electrical service main disconnect and electrical distribution panel are shown as 2 separate items, however newer circuit breaker distribution panels have the main disconnect located at the top of the electrical distribution panel (large circuit breaker).