Detcon CX-IR - Manual (Page 11)

Model CX-IR
When mounting on a pole, secure the junction box to a suitable mounting plate and attach the mounting plate
to the pole using U-Bolts. (Pole-Mounting brackets for Detcon junction boxes are available separately.)
2.4 Electrical Installation
The sensor assembly wiring should be installed in accordance with local electrical codes. Proper electrical
installation of the gas sensor is critical for conformance to electrical codes and to avoid damage due to water
leakage.
If a conduit run exists, a drain should be incorporated. The drain allows condensation inside the conduit run to
drain safely away from the sensor assembly. Electrical seals act as a secondary seal to prevent water from
entering the wiring enclosure. However, electrical seals are not designed to provide an absolute watertight seal,
especially when used in the vertical orientation. The electrical seal fitting is required to meet the National
Electrical Code per NEC Article 500-3d (or Canadian Electrical Code Handbook Part 1 Section 18-154).
Requirements for locations of electrical seals are covered under NEC Article 501-5.
NOTE
A conduit seal is required to be located within 18" of the J-Box and sensor assembly.
Crouse Hinds type EYS2, EYD2 or equivalent are suitable for this purpose.
NOTE Water damage from water leaking into the enclosure is not covered by the Detcon warranty.
NOTE
Unused ports should be blocked with suitable
3
/
4
" male NPT plug. Detcon supplies one
3
/
4
"
NPT male plug with each J-box enclosure. If connections are other than 3 /
4
" NPT, use an
appropriate male plug of like construction material.
CAUTION
Do not apply system power to the sensor until all wiring is properly terminated
(Section 2.5).
2.5 Field Wiring
Detcon Model CX-IR sensor assemblies require three conductor connections between power supplies and host
electronic controller’s 4-20mA output. Wiring designations are + (DC), – (DC), and mA (sensor signal.
Maximum wire ohmic resistance between sensor and 24VDC source is defined below. Maximum wire size for
termination in the Detcon J-Box accessory is 14 gauge.
Max Resistance drop on red and black wire is 10 ohms. This considers wire diameter, wire length and
maximum operation temperature.
Max loop load resistance between green and black wire is 500 ohms. Minimum loop load resistance between
green and black wire is 100 ohms. This is considers wire diameter, wire length, max operating temperature
and selected termination resistor.
AWG Wire Dia.
Over-Current
Protection
22 0.723mm 3A
20 0.812mm 5A
18 1.024mm 7A
16 1.291mm 10A
14 1.628mm 20A
Table 1 Protection vs. Wire Gauge
CX-IR Instruction Manual Rev. 1.2 Page 7 of 34