Honeywell NOTIFIER SFP-10UD Series Manual page 42

Installation
To calculate the wire gauge that must be used to connect ANN-BUS modules to the FACP, it is nec-
essary to calculate the total worst case current draw for all modules on a single 4-conductor bus.
The total worst case current draw is calculated by adding the individual worst case currents for each
module. The individual worst case values are shown in the following table:
N-ANN-80(C) LCD Annunciator/Indicator
N-ANN-S/PG Serial/Parallel Printer Interface Module
N-ANN-I/O LED Driver Module
N-ANN-LED Annunciator Module
N-ANN-RLY Relay Module
1 Total worst case current draw on a single ANN-BUS cannot exceed 0.5 amp
After calculating the total worst case current draw, Table 2.1 specifies the maximum distance the
modules can be located from the FACP on a single wire run. The table ensures 6.0 volts of line
drop maximum. In general, the wire length is limited by resistance, but for heavier wire gauges,
capacitance is the limiting factor.
These cases are marked in the chart with an asterisk (*). Maximum length can never be more than
6,000 feet (1,800 m), regardless of gauge used. The formula used to generate this chart is shown in
the note below.
Total Worst Case Current
Draw (amps)
0.100
0.200
0.300
0.400
0.500
The following formulas were used to generate the wire distance chart:
Maximum Resistance (Ohms)
Maximum Wire Length (feet)
(6,000 feet maximum)
where: Rpu = Ohms per 1,000 feet for various Wire Gauges (see table below)
42
Model Number
24 VDC Power Wiring Distance: ANN-BUS Modules to FACP
22 Gauge
1,852 ft.
926 ft.
617 ft.
463 ft.
370 ft.
Table 2.1 Wiring Distances
=
Total Worst Case Current Draw (amps)
Maximum Resistance (Ohms)
=
SFP-5UD & SFP-10UD Series Manual— P/N 52879:C2 1/24/2012
18 Gauge 16 Gauge
4,688 ft. * 6,000 ft.
2,344 ft. 3,731 ft.
1,563 ft. 2,488 ft.
1,172 ft. 1,866 ft.
938 ft. 1,493 ft.
6.0 Volts
Rpu
ANN-BUS Devices
1
Worst Case Current Draw
0.040 amps
0.040 amps
0.200 amps
0.068 amps
0.075 amps
.
14 Gauge
* 6,000 ft.
5,906 ft.
3,937 ft.
2,953 ft.
2,362 ft.
*500