ABSTRACT
This chapter explains how to make sure the facility has a good clean power supply for the security systems. The single line diagram shows which circuits are for lighting, which are for equipment, etc. and it shows where the circuit breakers are that control those circuits. When the diesel engine of an emergency generator starts, it still have the ability to carry all of the power loads, so a device called an automatic transfer switch is located between the emergency generators and the distribution panels. When the power has stabilized, the automatic transfer switch transfers the power cables to the emergency generator and leaves the power lines to the utility open. The same thing is going to happen when the power is restored, because the transfer switch has to switch back to the main power supply and momentary flicker or power interruption ensues.
