This device is designed to perform a short-circuit and the earthing of a low voltage network A.B.C. (Aerial Bundled Conductors).
It is connected to the MICHAUD 3-poles type pole-mounted Gang Fuse Switch Disconnector (Gang FSD).
https://www.youtube.com/watch?v=UV8TTGVqlLg&list=PLzqaALAjp8Z8PnhKz_m4N1B8RoEGsZLIu&index=6