NPLFA vs PLFA

[RenoRich]

Could someone please give a non-electrically minded person examples of what would be non-power limited, and power-limited fire alarm circuits.
Then only basic anything that I have heard in the past is that NPLFA circuits are more or less old school and havent been used in years. Is this true?
In the Fire Alarm world, we typically only deal with 120VAC for input power to the FACP. Is that considered non-power limited? All the circuits coming from the FACP are either IDC/SLC circuits, or NAC circuits, which I am assuming are power limited, but thats as far as I can guess.

This has been brought to the forefront because of a job at a University that the previous company installed the SLC circuit in the same conduit as 120VAC circuit that powers the 120V smokes in the dorms, and consequently there is noise on the SLC circuit causing troubles.

Thanks any and all.

 

[don_resqcapt19]

The input power has nothing to do with the actual fire alarm circuit. The power limited and non-power limited circuits are fed from the fire alarm control panel.

The signaling line circuit would be a power limited circuit and is not permitted in the same raceway with a 120 volt circuit. See 760.136.

 

[RenoRich]

Thanks Don....could you give me an example of a NPLFA circuit? Is it more or less extinct in the Fire Alarm world?

 

[gadfly56]

Thanks Don....could you give me an example of a NPLFA circuit? Is it more or less extinct in the Fire Alarm world?

Pyrotronics F3/5A ionization smoke detector. It ran somewhere around 240 volts. Don't test that circuit licking your fingers and then grabbing the wires.

In modern days, the Siemens ZAM-180 amplifier for voice systems has a non-power limited output.