Incident Report: Power Line Damage at Rybacken, September 1946

This document is a field report detailing an investigation into power line damage occurring on September 14, 1946, in the vicinity of Rybacken and Ulvhäll, Sweden. An investigator named Eriksson arrived at the scene following reports of damage. He observed that the middle wire of the Granhammar line was broken approximately 28 meters southeast of a utility pole near a residence in Rybacken. Notably, Eriksson found a bulge in a wire that remained attached to a pole, which led him to conclude that the wire had been struck by an object moving through the air. Further investigation at a location known as 'påsticket' near Ulvhäll revealed that the middle phase of the power line had fallen to the ground, with one end still attached to an insulator. The wire, consisting of 16 mm² sinklina, had been burned near the insulator. The report notes that such failures had not previously occurred on this 3000-volt, 3-phase power line, and no power outages had occurred in the preceding six weeks. Weather conditions at the time were described as calm with temperatures between 14 and 15 degrees Celsius and heavy rain, but no thunder or lightning was observed. The report also includes the testimony of Karl Axel Zetterberg, a farm worker born in 1904, who resided in Rybacken. Zetterberg stated that on the afternoon of September 14, 1946, at approximately 16:30, he was standing by his window looking toward the site of the power line failure when he suddenly heard a 'cracking' sound and simultaneously observed a light-green light.