The requirements of this technical report apply to residual current operated protective devices (hereinafter referred to as "residual current devices" (RCD)) for rated voltages not exceeding 440 V a.c., intended primarily for protection against shock hazard. They are intended to be used by technical committees when drafting product standards and apply only if they are incorporated or are referred to in the relevant standards. This report is not intended to be used as a stand-alone standard, for example, for certification. IEC 60755 has been revised in order to align the previous version with the latest editions of IEC 61008, IEC 61009, IEC 62423 and IEC 60947-2. This second edition of IEC 60755 cancels and replaces the first edition published in 1983.