an electric cable joint comprises at least one inner component heat - shrunk onto a cable or on to at least one part of a cable and at least one outer component of resilient material which is an interference fit with the inner component . the heat - shrink component takes up considerable variation in the size of the underlying cable so that a range of cable sizes can be accommodated by a much smaller number of inner component sizes than in a purely &# 34 ; slip - on &# 34 ; range .