A current transformer is described which comprises a housing having one or more apertures, each for receiving a primary cable or busbar, one or more magnetic cores enclosed within the housing and being positioned proximate to respective ones of the apertures so that a magnetic field is produced in a magnetic core when a primary current flows through a primary cable or busbar received through the respective aperture, and one or more secondary windings enclosed within the housing, each secondary winding being wrapped around at least a portion of a respective magnetic core so that a secondary current is induced in a secondary winding when a magnetic field is produced in the respective magnetic core. Shunt circuitry is enclosed within the housing and is connected across the secondary windings to generate a respective voltage signal for each secondary winding. A connector socket is integrally mounted to the housing for outputting the voltage signals. In this way, the labor costs incurred during installation of the current transformer can be reduced, a risk of wiring errors can be avoided, and a risk of electrocution from secondary terminals being left open-circuit is removed.