GWF-7075 Manual —
LS10147-002GF-E:G 10/5/2022
23
Wiring Specifications
Control Panel Installation
To calculate the wire gauge that must be used to connect SBUS modules to the 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.
After calculating the total worst case current draw, Table 4.6 specifies the maximum distance the modules can be located from the panel 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, regardless of gauge used. (The
formula used to generate this chart is shown in the chart below).
The following formulas were used to generate the wire distance chart.
Wiring Distance Calculation Example
Suppose a system is configured with the following SBUS modules:
2 - RA-1000/R Fire Annunciators
1 - GFPS-6S NAC Expander
1 - 5824 Parallel/Serial Interface
NOTE:
Total worst case current draw on a single SBUS cannot exceed 1 amp.
Model Number
Worst Case Current Draw
RA-1000/R Fire Annunciators
0.120 amps
5824 Serial/Parallel Printer Interface Module
0.045 amps
5880 LED I/O Module
0.250 amps
GFPS-6S NAC Expander
0.010 amps
CELL-MOD/CELL-CAB-GWF
0.145 amps
Table 4.5 SBUS Device Current Draw
Wiring Distance: SBUS Modules to Panel
Total Worst Case
Current Draw (amps)
22 Gauge
18 Gauge
16 Gauge
14 Gauge
0.100
1852 ft.
4688 ft.
* 6000 ft.
* 6000 ft.
0.200
926 ft.
2344 ft.
3731 ft.
5906 ft.
0.300
617 ft.
1563 ft.
2488 ft.
3937 ft.
0.400
463 ft.
1172 ft.
1866 ft.
2953 ft.
0.500
370 ft.
938 ft.
1493 ft.
2362 ft.
0.600
309 ft.
781 ft.
1244 ft.
1969 ft.
0.700
265 ft.
670 ft.
1066 ft.
1687 ft.
0.800
231 ft.
586 ft.
933 ft.
1476 ft.
0.900
206 ft.
521 ft.
829 ft.
1312 ft.
1.000 (Max)
185 ft.
469 ft.
746 ft.
1181 ft.
Table 4.6 Wire Distances Per Wire Gauge
Maximum Resistance (Ohms) =
6.0 Volts
Total Worst Case Current Draw (amps)
Maximum Wire Length (Feet) =
(6000 feet maximum)
Maximum Resistance (Ohms)
* 500
Rpu
where: Rpu = Ohms per 1000 feet for various Wire Gauges (see table below)
Wire Gauge
Ohms per 1000 feet (Rpu)
22
16.2
18
6.4
16
4.02
14
2.54
Table 4.7 Typical Wire Resistance Per 1,000 ft.
