Recent work by Western Power crews on the power pole that sparked the Perth Hills bushfire may have contributed to the structure failing.
Stuart Campbell, the son of 82-year-old Noreen Campbell whose Granite Road block was the ignition point for Sunday's blaze, said Western Power crews installed a new public pole along Johnston Road late last year.
Mr Campbell said the work had involved disconnecting and reconnecting powerlines on the felled pole and could have strained the wooden structure, which he estimated to be more than 30 years old.
"Certainly we're suggesting to investigators that (Western Power's work on the pole) could have been a contributing factor," Mr Campbell said.
"It's definitely a possibility the work contributed to it falling down, maybe if they hadn't done (the work) it would have fallen down in 10 years or we would have replaced it before then."
Mr Campbell said Western Power made no report of faults when completing the work. Western Power confirmed last night it had replaced 80 poles in Parkerville during the past six months as part of a $1.16 million network upgrade.
A spokeswoman said the utility was unable to comment on the private power pole because of an investigation by EnergySafety.
Mr Campbell said WA's system where landholders were responsible for maintaining and inspecting private powerlines and poles was impractical.
"There are so many poles and so many owners that have varying levels of competence and ability to assess it," he said.
It is advised homeowners assess their powerlines at least once a year but Mr Campbell said he checked the pole almost monthly because it was a "target" in his regular games of frisbee golf with friends.
Mr Campbell said he expected a lot of people to be angry.
"I can't think of anything I could say (to comfort victims) - probably that I'm sorry," he said, adding his mum was in good health for her age but "badly upset" over the fire.