How do I calculate if my notification appliance load exceeds the FX-10 NAC circuit ratings?

To determine if your load exceeds FX-10 ratings, you must verify that the total current draw is within panel limits and that the voltage drop does not exceed the operating minimum. The FX-10 supports a maximum of 2.0 A per NAC and a total of 7.0 A for the entire panel (Page 6) [1].

1. Sum the maximum operating currents for all appliances on the circuit using their Full-Wave Rectified (FWR) ratings (Page 77) [1].

2. Ensure the circuit total is 2.0 A or less and the sum of all NACs is 7.0 A or less (Page 6) [1].

3. Calculate the terminal voltage under load using the formula Vm = 20.4 V - (Itotal x 0.20 V/A) (Page 77) [1].

4. Subtract 16 V from Vm to find your allowable voltage drop (Page 77) [1].

5. Calculate the maximum allowable wire resistance using Rmax = Voltage Drop / Itotal (Page 77) [1].

6. Verify that your wire run resistance does not exceed Rmax based on the cable gauge and length (Page 77) [1].