Slack loop test, as the name indicates is applicable to the installed cables where we need to keep loops (Slacks). Usually, slacks are required for conventional aerial or underground cables in order to do future repairing/reconnection and maintenance.
Slack loop test is an environmental performance test devised by Corning Cable Systems for Figure-8 Aerial drop cables.
Aerial drop cables are used for connecting the distribution cable to the subscriber building. For maintenance and future jointing/repairing work, it is necessary to keep loops near the pole. As you know, a conventional Figure-8 aerial drop cable use metallic messenger wire for self-support to hang between two points and also to provide tensile strength during installation.
Figure-8 aerial drop cable structure has two distinct parts such as Messenger wire and Cable body. The metallic Messenger wire has a different thermal expansion coefficient when compared to that of the sheathing material (polyethylene) used for making the Cable body. At minus temperature, the Cable body shrinks more in comparison with the Metallic Messenger wire. This causes buckles in the cable body that results in the macrobend loss. In order to check and differentiate the macrobend loss increase, the manufacturer devised a separate test method called Slack Loop Test for aerial drop cables.