SPC-ET Beam Smoke Detector 5-100mSPC ET Beam Smoke Detector 5 100m Model SPC ET is a two wire beam smoke detector that consists of an emitter and receiver that cover a distance of 5 100 m providing a maximum coverage of 1500 m2. When used on a conventional system the emitter and receiver can be powered directly from the zone or if required the emitter also has an option to be powered from a separate 24 V dc supply. The SPC ET can also be interfaced to Hochikis ESP system, the