Vector says it doesn't know what caused a transformer to burst into flames in Albany.
Video provided to Newshub by a witness shows flames licking up the side of the transformer before it explodes with a deafening bang.
A spokesperson for Vector did not describe the incident as an explosion saying instead the transformer had caught fire.
They said the cause of the fire is unknown.
"Once the transformer has been repaired, crews will conduct an investigation to determine the cause," they told Newshub.
Witness Kristelle Williams told Newshub the experience was "pretty scary".
"I felt it shake the whole building," she said.
Williams says she and her co-workers were told to keep their distance from the transformer as it burnt. The flames lasted nearly half an hour before being extinguished, but the generator continued to smoke.
"It was quite scary when it was on fire - but also pretty exciting!" Williams said.