Underground Cable Locator Theory & Application

As a transmitter emits electromagnetic waves, a magnetic field is generated. If a metal pipe or a cable is laid within the magnetic field, induced current (signal current) is produced and flows through the underground metal pipe or cable according to the principle of electromagnetic induction.

Then, a receiver picks up the magnetic field generated by the subsurface metal pipe or cable.

The location and depth of the subsurface pipe or cable is located by the angle of the magnetic force concentrically generated by the metal pipe and the strength of the magnetic field.

Optional External Coil (Inductive clamp mode) available for locating Utility-line that has an insulated coating and for Power-line and Telephone-line that cannot be connected directly in the direct mode (Inject mode). 

Any metal object is buried underground, such as the metal reinforment underneath the concret floor will distort the waveform, therefore affects the depth measurement.

WARNING: The accuracy of depth measurement is subject to a number of factors and is meant as a guide only. Never use the depth measurement to define mechanical digging depths. Always follow local safe digging guidelines.

from RadioDetection

16mm rodder was pushed 225m over 50mm conduit, pictured at 218m.