FIELD: electrical engineering. SUBSTANCE: invention is intended for usage in power generating equipment to increase localization capabilities of electric plants including cabinets of factory-assembled switch-gears, factory-assembled transformer substations, factory-assembled current leads if open electric arc strike in them. Device has sensitive element in the form of dielectric fusible light guide with translucent sheath which one end carries butt mirror, beam splitter, optical radiation source, photodetector, electron solving unit, actuator and fault indicator. Second end of light guide is optically coupled via beam splitter to input of optical radiation source and input of photodetector. Output of the latter is connected to input of electron solving unit which outputs are correspondingly connected to actuator and fault indicator. EFFECT: expanded functional capabilities of device thanks to constant monitoring of its serviceability during operation. 7 dwg
