Spectrex 40/40U-UB - UV Flame Detector - Manual (Page 61)

General Instructions for Electrical Wiring 49
B Wiring Instructions
➣ In this appendix…
General Instructions for Electrical Wiring page 49
Typical Wiring Configurations page 51
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 100 ft. Ohm per 100 m
26 0.12 - 0.15 4.32 14.15
24 0.16 - 0.24 3.42 11.22
22 0.30 - 0.38 1.71 5.60
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
12 3.09 - 3.40 0.17 0.55
10 4.56 - 6.64 0.11 0.35
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 one circuit.
 Select wiring Length per your installation requirements.
 Refer to Power Supply Range for voltage extreme applied.