The line fell as she had been driving along Richardson St, in South Dunedin.
"I braked and we didn’t know if it was a power line so we had to stay in the car.
"I was really in shock because I had my child in the car."
Ms Anderson and her 11-year-old son, Seb Grenfell, waited about 10 minutes for emergency services to arrive, while yelling out to others who were trying to pass, to warn them of the fallen line.
"It was a horrible feeling," she said.
Emergency services confirmed it was a phone line and they were safe to leave their car.
A police spokeswoman said it appeared the line came down on its own.
