The ability of a device or system to function satisfactorily in its electromagnetic environment without introducing intorable electromagnetic disturbances to anything in that environment. Immunity - The ability of a device, equipment or system to perform without degradation in the presence of electromagnetic disturbance. There is no EMC of equipment if a noise is too high or equipment immunity is too low. Now it is impossible to sale electrical and electronic equipment in Europe without certificate of compliance with EMC standards. There is EMC certification in Russia too.
Competent body can give certificate on the base of test report.
All equipment must be tested in accredited laboratory. Emission tests are intendent to measure of electromagnetic noise generated by equipment. Many standards are under consideration. Russian standards will be harmonized with EMC European Norms. A voltage dip may be caused by switching operations and by faults.