Bleedover

When a signal applied to one buried line couples onto neighbouring metal and appears to come from it too. Bleedover produces ghost traces and distorted depth readings, and it is the most common source of error in congested corridors.

Gas, water, and electrical grounding systems are frequently bonded together, and any two conductors running close and parallel will couple. The result is that a locator following what looks like a clean trace may be following a neighbouring line, or a blend of several. Experienced operators manage it by choosing a lower frequency where the physics allows, connecting directly rather than inducing, checking that signal current falls off the way a single line should, and treating a suspiciously strong or suspiciously shallow reading as a warning rather than a result.