I’m resting the manual for my new panel and this is all it says for all the NACs. What the heck does this mean? Also,
With a Fire Lite MS-5UD-3 Panel, if two wires on a NAC short, will this break the panel, or will it just result in a trouble. This happens in my system occasionally cuz I’m clumsy (lol). I just want to know to be more cautious.
I’m not sure, because the 4004 uses a different terminal type, except that Simplex references the same thing in their manual as well. I think it has something to do with the NAC output or something.
Power-limited wiring refers to a circuit whose voltage is inherently limited. For fire alarm panels, the circuit voltages are limited to 24V by the transformer, hence the designations as a “power limited circuit.”
Non-power limited circuits, such as household 120V circuits, are subject to potential voltage surges, overcurrents, etc.
Some panels will be able to detect a short and shut down the NAC before any damage occurs, but it is never a safe practice to allow shorts to happen.
A direct short is in fact one example of how these power-limited circuits are beneficial: rather than drawing high currents through the short and potentially resulting in further damage to the board or a fire, the circuit will be protected by the fuse.