This standard is applicable to electrical equipment and the instrumentation and control equipment (I & C) of the safety system that is used in nuclear power generating stations including components or equipment of any interface whose failure could adversely affect the perform ance of the safety system. This standard presents acceptable seismic qualification methods and requirements to demonstrate that electrical and I & C equipment can perform their safety-related functions during and after an earthquake. As seismic qualification is only a part of equipment qualification, this standard shall be used in conjunction with IEC 780.