<p>The sleeve is assembled from an undershell (2) having a fixed portion (2a) and a withdrawable insert (7), and a cover (3) joined to it by a longitudinal hinge (5) and secured in the closed position by clasps (6). The cable entries (4) are sited on the line (8) of separation between the fixed portion of the undershell and the insert, whose top edge lies in the plane of sealing (68) between the undershell and the cover. Cable grippers are fixed into interior chambers.</p>
