Patent ID: 9594183
Date: 2017-03-14
CPC Classifications: G01V

Claim:
1. A method for detecting buried services by electromagnetic means with introducing an artificially generated electrical detection signal as an alternating electrical current of a desired frequency from a current-source, indirectly via soil to the buried service, detecting an electromagnetic field originating from the introduced underground detection signal, which is floating along the buried services, by a mobile detection unit above ground, wherein the unit is electrically insulated from the ground, and determining the proximity of the buried services to the detection unit according to the detected electromagnetic field of the detection signal, wherein, the soil conducted detection signal is supplied via a mains socket, in such a way that a flow path of the detection signal is: from the current-source to a first conductor of mains wiring at the socket, via the first conductor from the socket to a remotely located substation of a mains supply network, where the first conductor is remotely grounded, so that the detection signal is conducted to soil material, floating through the soil material and following at least a part of the buried service as path of least resistance within the soil material, from the buried service through soil material to a domestic earthing point, where a second conductor of mains wiring is grounded, and via the second conductor to the mains socket and back to the current-source.