Electromagnetic Interference Suppression Capacitor KEMET's Electromagnetic Interference Suppression Capacitors meet EN/IEC 60384-17:2005 standards and are subdivided into two groups, X and Y. X Capacitors are for use in positions where a failure of the capacitor would not expose anybody to the danger of electric shock. Y Capacitors are for use in positions where a failure of the capacitor could expose somebody to a dangerous electric shock.