Remote Booster Power Supply Technical Reference Manual
39
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.”
Worksheet 1: NAC cable length
NAC1 NAC2 NAC3 NAC4
Total operating current [1]
A
Load factor
×
0.59
0.59
0.59
0.59
V/A
Load voltage drop
=
V
Source voltage
19.1
19.1
19.1
19.1
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 DC power. See
the appliance installation sheets for operating currents.
[2] This voltage drop is valid for regulated notification appliances only. For special application
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 11 on page 40.
