Chapter 4 | System Wiring
Introduction
This chapter outlines the steps required for wiring the gas monitor.
These steps include the following:
Wiring Preparation
Sensor Wiring
Alarm Relay Wiring
Power and Output Wiring
ModBus Interface Wiring
Each of these steps is outlined in the sections that follow.
IMPORTANT: Perform all wiring in accordance with local electrical codes
and local authorities having jurisdiction.
IMPORTANT: DC signal and AC power should not be run in the same
conduit.
NOTE: All field wiring colors are arbitrary (unless provided by ISC).
Wiring Preparation
1. Collect the appropriate types and lengths of wire.
For control wire, use #18 AWG (0.9 mm²) insulated, shielded
cable.
For analog signal and power wire, use three-conductor (or four-
conductor for dual channel) #18 AWG (0.9 mm²) insulated and
shielded cable.
For digital ModBus signal and power, use a minimum of five-
conductor #18 AWG (0.9 mm²) insulated and shielded cable.
2. Power down the unit.
3. Unthread the windowed top from the housing.
4. Gently pull out the electronics module and place it safely to the side
of the unit.