Precise localization methods
Power cables: fault location methods

As we saw in [ , § 2 ], pre-location methods can only provide a measurement with an uncertainty of between a few percent and 15-20%. The accuracy of the measurement will depend on the quality of the echometer's calibration, precise knowledge of the link's characteristics and the method used.

It's not reasonable to take the risk of having an excavation carried out on this "simple" pre-location. It's economically unrealistic....