The utility model relates to a box spanner for insulating bar, including wrench body, the wrench body inner end meets and the nut is add to the double -screw bolt other end outside the linking arm with the inside double -screw bolt of linking arm, and simultaneously, be equipped with the ratchet in the linking arm inner chamber, this linking arm afterbody passes through the through bolt and connects one section action bars, the action bars constitutes by the strip shaped metal piece with the linking arm, and every metal block is hollow structure. The utility model discloses beneficial effect does: through setting up this for action bars box spanner, guaranteed not only to have reduced intensity of labour through the feasibility of the electrified tightening wire clamp bolt of the mode operation of earth potential operation, improved work efficiency, also reduced operator person's quantity on the pole, more can answer wide this type of of counter point multiaspect to disappear and lack working characteristics.