Wiring Distance Calculation Example - Fire-Lite MS-9200UDLS Manual

Product Description
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)
Exception: When using the ANN-RLY module, the installer must ensure that the maximum
24VDC power line drop does not exceed 0.3 volts. This results in the following wiring limitations:

Wiring Distance Calculation Example:

Suppose a system is configured with the following ANN-BUS modules:
• 3 ANN-80 Remote Fire Annunciators
• 1 ANN-S/PG Serial/Parallel Printer Interface Module
The total worst case current is calculated as follows:
ANN-80 Current Draw
ANN-S/PG Current Draw
Total Worst Case Current Draw
Using this value and referring to the Wiring Distance Table 1.1 on page 23, it can be found that the
available options are:
926 feet maximum using 22 Gauge wire

2,344 feet maximum using 18 Gauge wire

3,731 feet maximum using 16 Gauge wire

5,906 feet maximum using 14 Gauge wire

24
6.0 Volts
=
Total Worst Case Current Draw (amps)
Maximum Resistance (Ohms)
=
Rpu
Wire Gauge
22
18
16
14
Wire Gauge
18
16
14
12
= 3 X 0.040 amps
= 1 X.0.040 amps
MS-9200UDLS/E/C Manual — P/N 52750:F 7/26/2010
Ohms per 1,000 feet (Rpu)
16.2
6.4
4.02
2.54
Maximum Wire Length
312 feet
497 feet
787 feet
1,250 feet
= 0.120 amps
= 0.040 amps
= 0.160 amps
Accessories
*500