INSTALLING DETECTOR WIRING

TM 10-6665-297-13&P 2-6 DETECTOR INSTALLATION (continued) 2-6.1 Installing Conduits (continued) Explosion-proof, weatherproof, diffusion-sampling Detector #800-086 ½ -14 NPT female thread Explosion-proof, weatherproof, diffusion sampling, corrosion-proof Detector #0023-7317 ½ -14 NPT female thread The #0023-4014 detector assembly is designed to mount directly in the duct to expose the detector element to the gases being sampled. Mount #0023-4014 detector in the following manner. 1. Locate a 1-¼" diameter hole in the duct wall so that detector body can be inserted through the plate assembly and project into the duct. 2. Secure the plate assembly to the duct wall using four sheet metal screws through holes provided. 3. Insert detector body into the plate assembly and secure by tightening the two knurled thumb screws. 4. ¾ " flexible conduit may be used to allow a convenient means of removing the detector assembly for servicing. NOTE: For potentially explosive areas, install wiring in accordance with National Electrical Code Articles 501-517, which specify explosion-proof fitting, conduit sealing, and special wiring techniques. 2-6.2 INSTALLING DETECTOR WIRING . Use good-quality wire or cable containing three conductors in one jacket. Install with a minimum number of splices. Cable laid in open trays near AC high-power lines, or circuits to equipment which may generate radio-frequency (RF) signals, commutation noise, or ignition noise, should be sheathed or shielded. The outer braid of shielded cable must not contact conduit or junction boxes, and must be grounded only at the control module end. The cable should contain green, black, and white wires. Maximum resistance allowable in black and green (A and R conduit wires is 2.5 ohms per wire (5 ohms total A and R loop resistance, with A and R wire resistances the same within 0.1 ohm). A 1. 25-ohm maximum resistance is allowable where two detectors share a common power lead from terminals A and R to a remote point where power leads split. Wire gauge may be determined with respect to length of wire run as follows: 23-9617 7/1/76 2-22