TM 10-6665-297-13&P2-6DETECTORINSTALLATIONS (continued)2-6.2InstallingDetectorWiring (continued)1. When both wire runs are within 20 percent of equal distance, consult Table 2-2 for appropriate wiregauge, and install same-size wire for both runs. Use of #16 AWG wire is desirable even for veryshort runs, and may be used to simplify wire selection where cost of wire is not greatly significant.2. If the two wire runs are of unequal lengths: First choose wire size from Table 2-2 for the longer run (ifmarginal, choose next size larger), then determine exact wire resistance from “OHM-PER-FOOT”column of Table 2-2. Next, for the second detector, choose a smaller wire gauge from Figure 2-17 toobtain as nearly as possible the same resistance as the wire for a longer run. (Both sensors mustoperate at nearly the same voltage; hence voltage drops in the two wire runs must be nearly equal.Voltage drop in wires can be computed by determining resistance in ohms for the length and size ofwire, then multiplying by 0.28 amps detector current. Where differences in voltage drops betweenleads must be reconciled, set detector operating voltage between the values measured at detectorsfor each in accordance with paragraph 2-6.9, step 7.)3. Signal return wires to terminals C1 and C2 may be #20 AWG or larger for distances to 1100 feet, or#18 or larger for greater distances.AWGOhms/1000 Ft.Feet/Ohmat 68°Fat 68°F6.4025318.631593101.01000121.6630142.5396164.0249186.41572010.299Table 2-2. Resistance of Standard Annealed Copper Wire (Values areapproximately, and will vary depending upon resistivity of specific conductorused.) (See also Resistance Graph, Figure 2-17.)2-6.2.1 InstallingSingleDetectoronCD800/830orCD802/832ControlUnit.Install a single detector as follows (Figures 2-8 through 2-11):NOTE:Do not disconnect 15-ohm paired resistors factory-installed on DET 2 terminals A, R,and C.1.Connect a green wire between detector active element lead (green, banded “A”) and controlmodule terminal marked DET 1, A.23-96177/1/762-23
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