A detector 1 for detecting a current carrying conductor has a pair of vertically spaced antennae 3, 5 to detect the magnetic radiation produced by a current carrying conductor as a result of one or both of the mains power supply or an electromagnetic signal which is induced in the conductor by a dedicated signal transmitter. The detector 1 continuously calculates the depth of a buried conductor and if the buried conductor is above a predetermined minimum depth then the detector 1 triggers an audio and/or visual alarm. By reducing the sensitivity of the antennae 3, 5, the lateral offset range for which the alarm sounds is reduced and the location of a buried conductor can be determined.