Electrode receptacle plug and method

An apparatus for an insulator tube in which a high-voltage conductor and an electrode of a high-voltage tube are connected. The insulator tube has a first end receiving the electrode, and the insulator tube is received by an open first end of a housing. The insulator tube and housing are connectable to mount the insulator tube and the housing to a structure. The apparatus is a plug having a tubular body adapted to extend through the opposite end of the insulator tube, and the plug has an inner ring within the tubular body adapted to receive and sealingly engage the high-voltage conductor. The plug also has outer rings extending from the tubular body that sealingly engage the insulator tube, thereby preventing moisture from exiting the insulator tube and causing a short circuit.