Cable Finder

a set of instruments used in finding the location and depth of a cable run for underground or underwater cables; it is also used to locate damaged areas of the cable strands when they are completely grounded.

A cable finder consists of an audio-frequency amplifier, an antenna (at the input), and earphones (at the output). Its principle of operation is based on the possibility of determining the intensity (or tension) of a magnetic field at various points along the cable run. The magnetic field around the cable is generated by an alternating current of low (audio) frequency, which is supplied by a generator connected to one end of the cable. The cable finder is moved in such a way as to produce maximum volume of sound in the earphones. The layout of a cable run for underground or underwater cables can be determined in this way for depths up to 300 m. The magnetic field—and consequently the volume of the sound in the earphones—weakens sharply at the location of a fault in the conductors (if the fault results in complete grounding).