Abstract: A completely self-enclosed, weatherproof expulsion interruption device is disclosed which includes a detachable, arc-suppressing tube assembly which can be readily replaced in the field as needed, in conjunction with novel spring-loaded expulsion actuation mechanism for quickly breaking a high voltage circuit with only a minimum of objectionable arcing across the internal tube contacts of the device. The interrupter is especially adapted for use with high voltage, manually operable, blade-type switches and safely overcomes problems associated with arcing across switch contact points during opening thereof. As the switchblade is opened and engages the actuating arm of the interrupter, current is passed in shunt relationship through the interrupter until the respective switch contacts are safely parted.