Questions remain after an investigation found that a recent triple zero outage was not caused by a lightning strike.
An investigation into a Telstra triple zero outage has ruled out a lighting strike as the culprit.
A fire in a Telstra cable pit near Orange in NSW on May 4 caused disruption to emergency calls around the country.
At the time, Telstra's chief executive Andy Penn pointed to bad weather, saying that "all of our evidence suggests it is a lightning strike".
But a NSW Rural Fire Service investigation has thrown up more questions than answers.
"All causes have been eliminated with the exception of electrical infrastructure or possible arson," chief superintendent Ben Millington said.
Mr Millington said there was "no lightning in the area at the time".
"That certainly has been ruled out following an analysis of data and information provided by the Bureau of Meteorology."
Mr Millington said a copy of their findings has been given to police, who may use as part of a "broader investigation".
He added that "the onus is on landowners to ensure their infrastructure is maintained and clear of vegetation to stop or prevent the impact of fire".
The outage is also currently under investigation by the federal government, which contracts Telstra to provide the emergency line.