A test arrangement for use in determining the location of a fault in an installation 10 comprising at least first and second conductors 22, 24 providing electrical connections between a surface located device 12 and a subsea located device 20, the test arrangement comprising a first module 26 operable to apply a common test signal between ground and the first and second conductors 22, 24, and a second module 28 operable to monitor the total current flowing through the first and second conductors 22, 24 at a subsea location.