| 摘要 |
A combined toroid/shunt device for detecting residual current in an electrical installation comprising a plurality of conductors such as a live conductor ( 2 ) and a neutral conductor ( 3 ) is described. The device comprises a toroid means ( 1, 4 ) for detecting an AC residual current within a first range and a plurality of resistive shunts ( 6 a) to ( 6 d) for connection in respective ones of the plurality of conductors. A current detection means ( 5, 7, 13 ) 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.
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