For their fire alarm control panels, most fire alarm manufactures make a supplemental power supply that is specifically made for Notification Appliances like horns and strobes. The horns and strobes are connected to the wires of the NAC circuit. Actually, in the rest of the building, the NAC circuit is outside the panel. NAC stands for the "Notification Appliance Circuit".
The power supplies have different names, like BPS (Booster Power Supply), SPX (Signal Power Expander), NAC Power Supply, etc.
Compatibility, though, is an issue. Compatibility means that two pieces of equipment have been tested and confirmed to work with each other by an outside testing laboratory like UL, FM, ULC, CE, CCC, etc. Once the combination of equipment has been confirmed to work together, the testing laboratory puts that on their list of working-together combinations: the combination is officially compatible, it's "Listed For Use".
If the two pieces of equipment have not been listed as compatible, no one knows if the combination will totally fail, fail only sometimes or under certain conditions, or actually work reliably.
Some power supplies are only compatible with specific fire alarm control panels. Some control panels require matching power supplies. The technical support team for the control panel's manufacturer will know what NAC power supplies can be used with their control panel.
When calling the technical support team, make sure to have the exact model number for the fire alarm control panel. Tell them exactly how the panel is being used, and what is the problem. They will tell you what is compatible with their control panel.
When installing the NAC power supply, read and follow the NAC power supply's manual, especially follow the wiring and installation instructions. These instructions also show how to perform the voltage drop calculations on the building's NAC circuits. The building's NAC circuit may not carry enough power to all of the horns and strobes; if the calculations aren't performed, you don't know.
You will find that the battery information, calculations, and wiring is also in the installation manual.
Follow the instructions shown in the fire alarm control panel's installation manual and the NAC booster power supply's installation manual. You can get the manual's off the web, or call the technical support team for the panel for more information.
Remember, the fire alarm system is a life-safety system; there is no "I can figure this out myself" in life-safety. Read the installation manual, that's what it's there for.
Douglas Krantz
