A system for locating a fault in a conductor composed of a first conductor portion and a second conductor portion separated from each other by the fault, the system including: a field generator , having: a first connection connectable to the first conductor portion; a first signal generator configured to apply a first oscillating signal between the first connection and an earth, the first oscillating signal having a frequency of between 1 and 20 kHz; a second connection connectable to the second conductor portion; a second signal generator configured to apply a second oscillating signal between the second conductor connection and an earth, the second oscillating signal having a frequency of between 1 and 20 kHz and being different to the first oscillating signal, and a mobile detector configured to detect an electric field produced by the application of the first oscillating signal to the first conductor portion and an electric field produced by the application of the second oscillating signal to the second conductor portion, the detector including: a capacitive sensor element ; a signal processor to which the sensor element is connected and having an output; and a monitor receiving the output from the signal processor and providing a signal to an operator to indicate the position of the fault, characterised in that the output from the signal processor provides a comparison to the operator between the electric field produced by the application of the first oscillating signal to the first conductor portion and the electric field produced from the application of the second oscillating signal to the second conductor portion. a field generator , having: a first connection connectable to the first conductor portion; a first signal generator configured to apply a first oscillating signal between the first connection and an earth, the first oscillating signal having a frequency of between 1 and 20 kHz; a second connection connectable to the second conductor portion; a second signal generator configured to apply a second oscillating signal between the second conductor connection and an earth, the second oscillating signal having a frequency of between 1 and 20 kHz and being different to the first oscillating signal, and a first connection connectable to the first conductor portion; a first signal generator configured to apply a first oscillating signal between the first connection and an earth, the first oscillating signal having a frequency of between 1 and 20 kHz; a second connection connectable to the second conductor portion; a second signal generator configured to apply a second oscillating signal between the second conductor connection and an earth, the second oscillating signal having a frequency of between 1 and 20 kHz and being different to the first oscillating signal, a mobile detector configured to detect an electric field produced by the application of the first oscillating signal to the first conductor portion and an electric field produced by the application of the second oscillating signal to the second conductor portion, the detector including: a capacitive sensor element ; a signal processor to which the sensor element is connected and having an output; and a monitor receiving the output from the signal processor and providing a signal to an operator to indicate the position of the fault, a capacitive sensor element ; a signal processor to which the sensor element is connected and having an output; and a monitor receiving the output from the signal processor and providing a signal to an operator to indicate the position of the fault, characterised in that the output from the signal processor provides a comparison to the operator between the electric field produced by the application of the first oscillating signal to the first conductor portion and the electric field produced from the application of the second oscillating signal to the second conductor portion. <EOS>