Detcon FP-624D - Manual (Page 14)

Model FP-624D
FP-624D Instruction Manual Rev. 1.2 Page 10 of 42
and 24VDC source is shown in the Table below. The maximum wire size for termination in the Junction Box
is 14 AWG.
Table 1 Wire Gauge vs. Distance
AWG Wire Dia. Meters Feet
Over-Current
Protection
22 0.723mm 700 2080 3A
20 0.812mm 1120 3350 5A
18 1.024mm 1750 5250 7A
16 1.291mm 2800 8400 10A
14 1.628mm 4480 13,440 20A
NOTE 1: Wiring table is based on stranded tinned copper wire and is designed to serve as a
reference only.
NOTE 2: Shielded cable is required for installations where cable trays or conduit runs include
high voltage lines or other possible sources of induced interference. Separate conduit runs are
highly recommended in these cases.
NOTE 3: The supply of power should be from an isolated source with over-current protection
as stipulated in Table 1 Wire Gauge vs. Distance.
NOTE 4: A 250 ohm load resistor is needed on the 4-20 mA line when it is not being used.
Terminal Connections
CAUTION: Do not apply System power to the sensor until all wiring is properly terminated. Refer
to Section 2.8 Initial Start Up
Figure 11 Sensor Connector PCB
a) Remove the junction box cover and unplug the Transmitter Module. Identify the terminal blocks for
customer wire connections.
Customer
Wiring
W
h
it
e
B
lu
e
Y
e
llo
w
B
la
c
k
Wiring to
LEL Sensor
Power (+ -)
4-20 mA
RS-485 (A,B)
F
a
u
lt
A
la
rm
2
A
la
rm
1