The Standard Digital Protectowire Heat Sensitive Cable (PHSC) linear heat detector is capable of sensing heat anywhere along its length and initiates an alarm once its fixed activation temperature is reached. Once the ambient temperature meets or exceeds its fixed temperature, the heat sensitive polymer weakens, which in turn allows the twisted spring steel conductors to make contact, which results in an electrical short that triggers an alarm signal. The Standard Digital (PHSC) Linear Heat Detector is designed to be used on a compatible fire alarm control module or panel. All Protectowire Linear Heat Detectors must be installed in accordance with applicable sections of NFPA 72 or as required by the local AHJ.