Secondary power will consist of either storage batteries, a combination of storage batteries that "float" on the system and an automatic generator, or multiple generators, one of which must start automatically. The generator supplies must be on a dedicated branch circuit.

There is almost no difference in the requirements or type of batteries used in a central station compared to a protected premises fire alarm system. 

The requirements for generators are more stringent, given the fact that there has to be a reliable backup power supply for a central station and that any generator arrangement must be reliable. If there is a single automatic starting generator, with float batteries, the generator installation and arrangement must conform to NFPA 70, National Electrical Code, article 701. If multiple generators are used, article 702 applies.

NOTE: This is an unformatted excerpt from our online fire protection training library.