IEC 60384-14 is the sectional specification for fixed capacitors intended for electromagnetic interference suppression and for direct connection to the supply mains. These components are safety-critical: a short circuit in a capacitor placed across the line, or a breakdown in one connected between line and earth, can start a fire or expose a user to mains potential, so the standard imposes requirements far stricter than those for ordinary capacitors. Capacitors are classified as X type, used between lines, and Y type, used between line and earth, and each class is subdivided according to the impulse voltage the component must withstand. The specification defines the preferred ratings, the permitted tolerances, and a test programme that includes voltage proof at power frequency and with impulses, insulation resistance and capacitance stability after damp heat, endurance testing at elevated temperature for a thousand hours, active flammability, and a destructive test in which the capacitor is subjected to a current surge that must not cause flaming. Marking and the safety approval information required on the body are also specified.