Appendix B: Worksheets
Vigilant VS1 and VS2 Technical Reference Manual
213
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 (64 point panel)
×
0.20
0.20
0.20
0.20
V/A
Load factor (250/500 point 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,”
later in this topic.
[3] Use the manufacturer’s published wire resistance expressed in ohms per foot. For typical values, see Table 1, later in this
topic.
