The linear heat detector (LHD) cable looks like a colored cable that has the ability to detect heat along its length. The LHD detector consists of two strands of conductive metal (wire) with a heat-sensitive thermoplastic polymer coating and woven together. If the temperature increases, the polymer coating of the two strands of wire is lost (according to the operating temperature). And this causes a short circuit; In short, whenever the temperature of the LHD cable increases, the two strands of wire inside it are connected together. This short circuit is recognized as a fire by the electronic circuits of the fire alarm panels
We can use the LHD in two conventional and addressable ways. In the conventional method, we can identify the fire zone using the LHD cable and two fire resistors and end of line (EOL), but in the addressable method, we can use a locator (an electronic device to determine the location of the short circuit in the LHD cable) and a map of the cable installation location. LHD we can identify the fire place.