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B-2
EXAMPLE NO. 1
Determine the recommended wire size for a daisy-chained, Class-B, Style-4 SLC with 160
devices and a total wire length of 7,500 feet. The total wire length is the sum of wiring for the
positive and negative SLC legs, and is not the linear distance from the control unit to the most-
remote device.
Try #14 AWG wire. The total SLC wiring resistance is:
7,500 ft. x 2.525 ohms / 1,000 ft. = 18.9 ohms.
If Coleman Cable wire is selected, P/N 98141 (from Recommended Wire Listing), the total SLC
wiring capacitance is:
3,750 ft x 20 x 10
Coleman Cable wire, PN 98141, is acceptable.
Note: Capacitance values correspond to a pair of wires as compared to resistance values that
correspond to a single conductor. The wire-pair length for this SLC is 3,750 feet, and this
value is used for the SLC's capacitance calculation.
B-3
EXAMPLE NO. 2
Determine the proper wire size for a Class-A, Style-6 SLC with 100 devices and a total wire
length 7,000 feet. The total wire length is the sum of wiring for the positive and negative SLC
legs for both the primary and redundant communications circuits, and is not the linear distance
from the control unit to the most remote device.
Try #18 AWG wire first. The total SLC wiring resistance is using #18 AWG is:
7,000 ft. x 6.385 ohms / 1,000 ft. = 44.7 ohms.
The total SLC wiring resistance (44.7 ohms) when using #18 AWG wire exceeds the maximum
SLC wiring resistance of 40.0 ohms. Use larger wire.
Try #16 AWG next. The total SLC wiring resistance using #16 AWG is:
7,000 ft. x 4.016 ohms / 1,000 ft. = 28.1 ohms.
The total SLC wiring resistance (28.1 ohms) when using #16 AWG wire is less than the
maximum SLC wiring resistance of 40 ohms. The SLC wiring resistance using #16 AWG wire is
acceptable.
If Coleman Cable wire is selected, P/N 98161 (from Recommended Wire Listing), the total SLC
wiring capacitance is:
3,500 ft x 20 x 10
Coleman Cable wire, P/N 98161, is acceptable.
P/N 06-236530-001
Wiring Requirements for ARIES Signaling Line
-12
farads / ft. = 0.075 x 10
-12
farads / ft. = 0.07 x 10
B-3
-6
farads (or, 0.075 F).
-6
farads (or, 0.07 F).
August 2013
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