Automatic Transfer Switch are electrical and manual control units that can automatically transfer the electrical load from the utility power lines to the emergency generator set, whenever a utility power failure occurs, and to transfer back to the utility power returns to normal.

Classification

The classification for Automatic Transfer Switching Units are either Class PC or Class CB. Class PC an ATS unit which is capable of making and withstanding shortcircuit currents but is not intended for breaking short circuit currents.

Class CB an ATS unit provided with overcurrent release and the main contacts are capable of making and are intended for breaking short circuit currents.