What is a Current Transformer (CT)?

A current transformer (CT) is a device used to measure electrical parameters within a circuit using electromagnetic induction. Sometimes referred to as a CT clamp, the electrical supply cable to to be monitored is fed through the centre of the CT core or more commonly the CT core ‘splits’ and can be connected around the cable. CT cores are sized for various voltages (V) and amps (A) have to be suitably sized for the cable size, voltages and current in use.