Installation of temperature-sensing cables on cable trays

Temperature-sensing cables in cable trays must be installed with proper spacing, secure mounting, and adherence to environmental and fire safety standards to ensure accurate monitoring and early fire detection.Key Installation Requirements1. Cable Placement and Mounting Temperature-sensing cables, such as Linear Heat Detection (LHD) or Hot Spot Detectors, should be installed on top of or above the power cables in the tray to accurately detect heat buildup . They are typically mounted in a sinusoidal or zigzag pattern to maximize coverage and ensure no hot spots are missed . Fixings or clips should be used at intervals of no more than 1.2 meters, and cable ties should include neoprene sleeves to prevent damage to the cable insulation . The cable should be installed no more than 200 mm above the tray to allow access while maintaining detection effectiveness . 2. Environmental Considerations Cables must be robust and resistant to dust, moisture, and temperature fluctuations, as cable trays often experience harsh conditions . Intrinsically safe sensors are recommended for hazardous locations . The outer polymer covering protects the inner core, but care must be taken to avoid bending or damaging the thermal-sensitive insulation during installation . 3. Cable Tray Configuration For trays wider than 600 mm, additional sensing cable runs are required to ensure full coverage . In multi-tiered trays, “V” clips can suspend the sensing cable over lower trays, and a length of cable beneath the lowest tray is recommended to detect debris or rubbish fires . Physical barriers and zoning should be considered for alarm and extinguishing system integration . 4. Electrical and System Integration Temperature-sensing cables should be connected to a supervised fire alarm control panel, PLC, or addressable switch monitor unit . Systems may include a Digital Location Interface (DLI) to monitor long cable runs (up to 2000 m) and provide precise alarm location . Periodic testing using test switches or sample ovens is recommended to verify functionality without replacing the cable . 5. Handling and Splicing Cables must be handled carefully to avoid damage to the inner thermal core . Splices should be wrapped with overlapping splicing tape to prevent moisture ingress, and low-temperature splicing tape should be used if installation occurs below 0°C . Painting the detection cable is not recommended as it can impair performance . 6. Compliance and Standards Installation should follow local fire regulations, manufacturer guidelines, and UL/FM requirements . The temperature rating of the cable must match the expected operating environment, similar to heat detectors or sprinklers . Continuous monitoring is essential for early detection of temperature anomalies and fire prevention . By following these requirements, temperature-sensing cables in cable trays can provide reliable, early warning of overheating or fire hazards, ensuring safety and operational continuity in industrial, commercial, and infrastructure facilities .