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Installation
2.7.1 ANN-BUS Wiring
This section contains information on calculating ANN-BUS wire distances and the types of wiring
configurations (Class B).
Calculating Wiring Distance for ANN-BUS Modules
The following instructions will guide the installer in determining the type of wire and the maximum
wiring distance that can be used with FACP ANN-BUS accessory modules.
To calculate the wire gauge that must be used to connect ANN-BUS modules to the FACP, it is
necessary 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:
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
1
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)
34
Model Number
ANN-80(C) LCD Annunciator/Indicator
ANN-S/PG Serial/Parallel Printer Interface Module
ANN-I/O LED Driver Module
ANN-LED Annunciator Module
ANN-RLY Relay Module
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)
=
1
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
Maximum Resistance (Ohms)
Rpu
MRP-2001 Series Manual — P/N 53040:H 1/26/2017
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
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