A lone magpie was the cause of a power outage affecting 6000 properties around Wanganui yesterday.

The incident occurred on the No 2 Line property of Denise Duncan, who said the bird had been sitting on a guidewire when it somehow touched two wires at the same time, causing the electricity to arc, electrocuting the bird and causing an insulator on the guidewire to blow apart.

There would have been a big bang, but because it had been perched on one of the high-voltage lines running across their farmland, the only ones to hear it were a mob of cattle, which took off at a run, she said.

The insulator fell to the ground, where it set fire to a wooden-staked fence and surrounding grass covering an area of about 18sqm.


Mrs Duncan said they saw the cattle running, and then noticed the smoke from their home on No 2 Line and went to investigate.

They realised as they neared the fire that it was connected with the powerlines and a wire was hanging loose, so they turned back and called the fire service.

Thankfully, the ground was not too dry, because the area was difficult to get to and required firefighters to approach from a property on Durie Vale Rd. From there, fire officers had to walk about 450m to the site of the fire, she said.

Power customers in Wanganui, Kaitoke, Kakatahi, Kaurangaroa, Mangamahu, Whangaehu Beach, Whangaehu Valley and Wanganui Matarawa were reportedly affected by the outage.

Powerco network operations manager Phil Marsh said such bird strikes were not uncommon and happened on average about once a month across their entire network.

Such outages occurred when birds either touched two wires at the same time, or one wire and and an electrical "ground" - like the pole, at the same time. This caused the electricity to run through the bird, and caused faults on the network.

Mr Marsh said power was restored by 2pm.

The Wanganui Chronicle building, on Taupo Quay, was among those affected, but power was restored by 11:30am.

Mrs Duncan said power in their area, which was fed by that line directly, did not come on until closer to 3pm.