Active locating can be used to estimate the depth of a buried line.

• A. True
• B. False
• C. Only when using conductive method
• D. Not applicable

Answer: (A)

Active locating uses a transmitter to energize the buried line, and the receiver detects that energized signal to determine where the line is and how deep it lies. The depth estimate comes from how the electromagnetic field from the energized line behaves in the ground—the strength and phase of the signal change with depth, so the instrument can translate those measurements into an approximate depth reading. This is why you can both locate the line and gauge how far below the surface it sits when you’re actively energizing it. Keep in mind the depth readout is an approximation and can be influenced by soil conductivity, moisture, backfill, line orientation, and other conditions. It’s common to verify depth with supplementary methods or potholing if a precise depth is required. Passive locating doesn’t energize the line, so it generally cannot provide a depth estimate, which is why depth determination is associated with active locating.