The Linear Heat Detection Cable (LHDC) is a continuous heat detector in the form of a cable. It can detect heat at any points along its entire length. The cable is composed of two twisted shield conductors insulated with a heat sensitive polymer, then wrapped with a protective tape and finished with an outer covering.
Linear Heat Detection Cable is available in resettable and non-resettable technology. The non-resettable cable is described as Digital and the resettable as Analogue.
800 Series Digital LHD Cable (Non-Resettable)
The 800 series is a fixed temperature and non-resettable digital cable. The cable contains insulators which melt at a specific temperature. At the rated temperature, the heat sensitive polymeric insulation creates pressure between conductors, permitting them make contact with each other thereby initiating an alarm signal at the control panel. The LHDC is installed in conjunction with an end-of-line (EOL) device for continuity monitoring and a junction box (optional) for leader wire connection.
900 Series Analogue LHD Cable (Resettable)
The 900 series is an analogue heat sensing cable containing insulators of which resistance varies proportionally to changes in temperature. Analogue cable is installed in conjunction with an end-of-line (EOL) device for continuity monitoring and a modulator providing selectable alarm thresholds (programmed before shipping), fire and fault outputs. This cable is self-restorable after the fire event as long as its temperature does not exceed specified resettable temperature limit of 120°C (248°F). Alarm temperature setting ranges between 70°C to 130°C (158°F to 266°F). Customer can specify its own alarm
temperature setting. The factory default setting is set at 85°C (185°F).