Underground Cable Detector and Cable Locator Guide

Updated: 28 October 2026

What is an underground cable detector?

An underground cable detector is a handheld receiver that senses the electromagnetic field around a buried metal conductor. Lifting and lowering it over the ground shows a peak or null directly above the cable, and most units display an estimated depth. The terms cable detector, cable locator and cable detector machine are used for the same kind of instrument; a cable and pipe locator simply adds a transmitter that can also trace metal pipes.

How does a cable locator work?

• Passive power mode picks up the 50 Hz field around loaded power cables.
• Passive radio mode detects radio energy that buried metal lines re-radiate.
• Active mode uses a transmitter, clamped or connected to one cable or pipe, so the receiver follows that line only. Direct connection gives the cleanest trace; induction is quicker but can light up neighbouring lines.
• Sonde mode follows a small transmitter pushed through a plastic duct or drain.

Our article on EM cable locators vs GPR compares the physics in detail.

Which type of cable detector do you need?

• Non-contact voltage testers and wall scanners find live wiring in walls, not buried cables.
• Basic underground cable detectors sweep a dig area for live power before excavation.
• Cable and pipe locator sets with a transmitter trace a specific line, measure depth and suit utilities, telecom and contractors.
• Cable fault locators are different: they find the failed point on one known cable, using a TDR and surge equipment rather than a field sensor.

What does a cable locator cost in India?

Cable locator price depends on modes, depth range and data logging. In October 2026, listings on Indian B2B marketplaces ranged from a few thousand rupees for simple detectors to roughly ₹1–5 lakh for professional transmitter-and-receiver sets. Add training and calibration; a locator read badly is worse than none. For occasional jobs, hiring a survey crew is usually cheaper than buying.

What can a cable detector not find?

A locator needs metal and a signal. It misses plastic water and gas pipes, empty HDPE ducts, dead or abandoned cables and fibre without a tracer wire. Close parallel cables blur into one trace, and depth readings drift near other services. That is why a route survey combines the locator with ground penetrating radar, which reads any material change, and marks each line on the ground.

When to call a survey team

For a single trench near known cables, a trained operator with a good locator may be enough. For HDD crossings, long trenches, busy city roads or sites with unknown history, book a combined EM and GPR survey. Mezux maps cable routes, joints and duct banks through its underground cable detection service; rates are on the GPR survey price list.

Sources

• IndiaMART – underground pipe and cable detector listings with prices (checked October 2026)
• ASTM D6432-19 – Standard Guide for Using the Surface GPR Method for Subsurface Investigation
• Mezux Touch field practice and published rate card (October 2026).