Table of Contents
Advertisement
4.4
SBUS Wiring
This section contains information on calculating SBUS wire distances and the types of wiring
configurations (Class B).
4.4.1
Calculating Wiring distance for SBUS modules
The following instructions will guide you in determining the type of wire and the maximum
wiring distance that can be used with control panel SBUS accessory modules.
To calculate the wire gauge that must be used to connect SBUS modules to the control panel,
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 table below.
Note: Total worst case current draw on a single SBUS cannot exceed 500 mA.
5635 Remote Fire Annunciator
After calculating the total worst case current draw, Table 4-1 specifies the maximum distance
the modules can be located from the panel on a single wire run. The table insures 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, regardless of gauge used. (The formula used to generate this chart is shown in
the note below).
Table 4-1: Wire Distance Per Wire Gauge Using Copper Wire
Total Worst Case
Current Draw (amps)
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000 (Max)
151450
Model Number
Wiring Distance: SBUS Modules to Panel
22 Gauge
18 Gauge
1852 ft.
4688 ft.
926 ft.
2344 ft.
617 ft.
1563 ft.
463 ft.
1172 ft.
370 ft.
938 ft.
309 ft.
781 ft.
265 ft.
670 ft.
231 ft.
586 ft.
206 ft.
521 ft.
185 ft.
469 ft.
Worst Case Current Draw
.04 amps
16 Gauge
* 6000 ft.
3731 ft.
2488 ft.
1866 ft.
1493 ft.
1244 ft.
1066 ft.
933 ft.
829 ft.
746 ft.
Control Panel Installation
14 Gauge
* 6000 ft.
5906 ft.
3937 ft.
2953 ft.
2362 ft.
1969 ft.
1687 ft.
1476 ft.
1312 ft.
1181 ft.
4-9
Advertisement
Table of Contents
