Wiring Instructions
TM40/40L Rev. (Ag), February 2019
65
Appendix B:
Wiring Instructions
B.1
General Instructions for Electrical Wiring
Follow the instructions detailed in this section for determining the correct wire
gauge to be used for the installation.
1
Use Table 23 to determine the required wire gauge/size for general wiring,
such as relay wiring. Calculate the permitted voltage drop with respect to load
current, wire gauge, and length of wires.
Table 23: Maximum DC Resistance at 68°F/20ºC for Copper Wire
AWG #
mm
2
Ohm per 100ft
Ohm per 100m
20
0.51
–
0.61
1.07
3.50
18
0.81
–
0.96
0.67
2.20
16
1.22
–
1.43
0.43
1.40
14
1.94
–
2.28
0.27
0.88
2
Use Table 24 to select wire gauge for power supply wires. DO NOT connect
any circuit or load to detectors’ supply inputs.
•
Select
number of detectors
connected in 1 circuit.
•
Select wiring
length
per your installation requirements.
•
Refer to
power supply range
for voltage extreme applied.
Table 24: Wiring Length (in ft/m)
Number
of
Detectors
Recommended Wire Diameter (AWG)
Power
Supply
Range
(VDC)
24
18
16
14
-
-
22
–
32
20
18
16
14
-
-
22
–
32
16
20
18
16
14
-
22
–
32
12
20
18
16
14
-
20
–
32
8
20
18
16
14
-
20
–
32
4 and less
20
18
16
16
14
20
–
32
ft/m
164/50
328/100 492/150 656/200 820/240
Max. Length from Power Supply to Last Detector
B.1.1
Calculation Formula
Use the following formula to calculate minimum wire gauge per wire length
between the power supply (controller) and the detector, considering the number
of detectors on the same power line, where: