Abstract: Apparatus (1) is for detecting electrical current in a support (2) for an overhead power line (3) adapted to carry AC electricity at a nominal frequency. The apparatus (I) comprises a first and a second electrical contact (16, 17). The first and second electrical contacts (16, 17) are adapted to be electrically coupled to the support (2) in spaced apart relationship, in use. A voltage detector (7) is coupled to the first and second contacts. A first voltage signal generator (11) is coupled to the first electrical contact (16) and is adapted to generate a voltage signal at a second frequency. A processor (15) is coupled to an output from the voltage detector (7). The voltage detector (7) is adapted to detect a first voltage differential between the first and second electrical contacts (16, I 7) at a first frequency corresponding to the nominal frequency, and to detect a second voltage differential between the two electrical contacts (16, 17) at the second frequency.