Installation |
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.
Wiring Distance:
Total Worst Case Current | 22 Gauge | 18 Gauge | 16 Gauge | 14 Gauge |
Draw (amps) |
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0.100 | 1,852 ft. | 4,688 ft. | * 6,000 ft. | *6,000 ft. |
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0.200 | 926 ft. | 2,344 ft. | 3,731 ft. | 5,906 ft. |
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0.300 | 617 ft. | 1,563 ft. | 2,488 ft. | 3,937 ft. |
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0.400 | 463 ft. | 1,172 ft. | 1,866 ft. | 2,953 ft. |
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0.500 | 370 ft. | 938 ft. | 1,493 ft. | 2,362 ft. |
Table 2.1 Wiring Distances
Note: The following formulas were used to generate the wire distance chart:
Maximum Resistance (Ohms) | = | 6.0 Volts |
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| Total Worst Case Current Draw (amps) |
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Maximum Wire Length (feet) | = | Maximum Resistance (Ohms) | *500 |
(6,000 feet maximum) |
| Rpu |
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where: Rpu = Ohms per 1,000 feet for various Wire Gauges (see table below)
Wire Gauge | Ohms per 1,000 feet (Rpu) |
22 | 16.2 |
18 | 6.4 |
16 | 4.02 |
14 | 2.54 |
Exception: When using the
Wire Gauge | Maximum Wire Length |
18 | 312 feet |
16 | 497 feet |
14 | 787 feet |
12 | 1,250 feet |
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