A non-incendive circuit is one in which any arc or thermal effect produced under intended operating conditions of the equipment is not capable, under specified test conditions, of igniting the flammable gas–air, vapor–air, or dust–air mixture.

Any component that does arc normally does so at any energy level too low to cause ignition and surface temperatures are not are above the temperature class under normal conditions.

Equipment certified using this protection method is suitable for use in Class I, II, III Division 2.