Measuring devices

Abstract

A combined toroid/shunt device for detecting residual current in an electrical installation comprising a plurality of conductors such as a live conductor () and a neutral conductor () is described. The device comprises a toroid means () for detecting an AC residual current within a first range and a plurality of resistive shunts () to () for connection in respective ones of the plurality of conductors. A current detection means () responsive to current flowing in each of said shunts for detecting a DC residual current and/or an AC residual current within a second range is described. The first range of AC residual current is an AC residual current resulting from earth leakage or cross-leakage between conductors up to a saturation level at which the toroid or electronic means associated means therewith becomes saturated. The second range includes an AC residual current of said saturation level.