Edwards Signaling eFSA250 - Manual (Page 229)

Appendix B: Worksheets
E-FSA64 and E-FSA250 Technical Reference Manual 217
Worksheet method
Use this worksheet to determine the maximum cable length of a notification
appliance circuit for a given number of appliances.
Use this worksheet only if all the appliances are regulated. That is, they must
have a minimum operating voltage of 16 V. For other appliances, use the
“Equation method.”
NAC cable length
NAC1 NAC2 NAC3 NAC4
Total operating current [1] A
Load factor (eFSA64 panel) × 0.20 0.20 0.20 0.20 V/A
Load factor (eFSA250 panel) 0.24 0.24 0.24 0.24
Load voltage drop = V
Source voltage 20.4 20.4 20.4 20.4 V
Load voltage drop − V
Minimum voltage = V
Regulated appliance voltage − 16.0 16.0 16.0 16.0 V
Voltage drop [2] = V
Total operating current ÷ A
Maximum resistance = Ω
Wire resistance (Ω/ft) [3] ÷
Maximum wire length = ft.
÷ 2 2 2 2
Maximum cable length = ft.
[1] Total of the maximum operating currents for all appliances as specified for FWR power. See
the appliance installation sheets for operating currents.
[2] This voltage drop is valid for regulated notification appliances only. For unregulated
appliances, see “Equation method” on page 218.
[3] Use the manufacturer’s published wire resistance expressed in ohms per foot. For typical
values, see Table 46 on page 218.