A falling power pole on the property of an 82-year-old woman sparked the Perth Hills firestorm that destroyed 55 dwellings but the government's energy safety regulator says she is unlikely to be penalised.

A falling power pole on the property of an 82-year-old woman sparked the Perth Hills firestorm that destroyed 55 dwellings but the government's energy safety regulator says she is unlikely to be penalised.