The most snow on a electrical cable was accumulated in Norway back in 1961.
On the 22kV cable in Voss, norway, it accumulated 1,5 meter with snow and ice. The pictures are from Lønahorgi, 1410 metre over the sea. Every meter of ice wegth 305 kilo.
That is equivalent with a WV beadle hanging side by side. The reason for the accumulation of ice that the cable itself was free spinning around it own center, allowing the ice to form equally around the cable without breaking of. If the cable was not spinning, the ice would have formed a wing like structure and broken off.
After this they changed the way og putting up cabel in the montains.