Most of the hardware on an electric pole should be grounded and the only attachment from the primary wire(s) to the pole is through an insulator or series of in

Most of the hardware on an electric pole should be grounded and the only attachment from the primary wire(s) to the pole is through an insulator or series of insulators. That said, if there's a bolt on or near the primary, it's possible it worked it's way out and started mechanically vibrating making contact between some induced voltage and ground say.