1: Calculating Wiring Distance For Sbus Modules - Honeywell 6820 Manual

Control Panel Installation
4.6.1 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 SBUS circuit. 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 1 amp. If a large number of accessory modules are required, and the
worst case current draw will exceed the 1 amp limit, then the current draw must be distributed using 5895XL Power Expanders. Each 5895XL
Power Expander provides an additional SBUS, with an additional 1 amp of SBUS current. Wiring distance calculations are done separately for
each 5895XL, and separately for each control panel SBUS.
NOTE: Refer to Table 3.2 for SK devices or Table 3.3 if using SD SLC devices for the maximum number of each type of device that can be
used per system.
After calculating the total worst case current draw, refer to Table 4.2 below for 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 note below.The following formulas were used to generate the wire distance chart:
Total Worst Case
Current Draw (amps)
1.000 (Max)
32
Model Number
6860, 6855, 5860 Fire Annunciators
5815XL SLC Loop
6815 SLC Loop Expander
5824 Serial/Parallel Printer Interface Module
5880 LED I/O Module
5865 LED Annunciator
5895XL Intelligent Power Supply
5496 NAC Expander
EVS-50W
EVS-125W
EVS-VCM / EVS-VCM with EVS-SW24
EVS-LOC / EVS-LOC with EVS-SW24
EVS-100W
EVS-100W with EVS-100WBU
SK-NIC Network Interface Card
CELL-MOD/CELL-CAB-SK
SK-F485C Fiber Converter
Table 4.1 SBUS Device Current Draw
1 All devices must use the same SBUS and VBUS.
2 When doing wire calculations, use .080 amps per device with .105 amps for the last device.
Wiring Distance: SBUS Modules to Panel
22 Gauge
0.100 1852 ft.
0.200 926 ft.
0.300 617 ft.
0.400 463 ft.
0.500 370 ft.
0.600 309 ft.
0.700 265 ft.
0.800 231 ft.
0.900 206 ft.
185 ft.
Table 4.2 Wire Distances Per Wire Gauge Using Copper Wire
Worst Case Current Draw
0.120 amps
0.150 amps
0.078 amps
0.040 amps
0.250 amps
0.200 amps
0.010 amps
0.010 amps
0.010 amps
0.010 amps
1
0.080 amps /0.105 amps
1
0.080 amps / 0.105 amps
0.010 amps
0.010 amps
0.021 amps
0.145 amps
0.125 amps
18 Gauge
4688 ft.
2344 ft.
1563 ft.
1172 ft.
938 ft.
781 ft.
670 ft.
586 ft.
521 ft.
469 ft.
6820/EVS Manual — P/N LS10144-001SK-E:E 4/6/2022
2
2
16 Gauge 14 Gauge
* 6000 ft. * 6000 ft.
3731 ft. 5906 ft.
2488 ft. 3937 ft.
1866 ft. 2953 ft.
1493 ft. 2362 ft.
1244 ft. 1969 ft.
1066 ft. 1687 ft.
933 ft. 1476 ft.
829 ft. 1312 ft.
746 ft. 1181 ft.
SBUS Wiring