Abstract: A re-enterable end cap for sealing and protecting an end of an exposed cable conductor while allowing repeated access to the cable by a metal test probe. The end cap has an outer tubular shell which is open at one end to receive the end of the cable and closed at the opposite end by a plug of rigid material. The tubular shell may be dimensionally recoverable. The plug has a hollow cavity which contains a deformable self-sealing material. Access to the interior of the end cap is provided through an aperture in an end wall of the plug. The hollow interior of the plug may be provided with a one-way valve member which permits the test probe to enter the plug while preventing excessive loss of the self-sealing material through the aperture in the end wall. The valve member may take the form of a ball having a diameter which is greater than the diameter of the aperture and which is embedded in the self-sealing material.