Photo: Screenshot / Unison
Power was out today to more than 35 suburbs in Rotorua.
Transpower spokesperson Nathan Green said the outage happened due to a fault at a Rotorua sub-station, shortly before 2pm.
Crew were doing routine work at the sub-station when a "switching error" occurred and caused an interruption to the supply of power to Unison. Green confirmed that it was a human error.
Transpower is investigating.
Unison said more than 22,000 customers were affected.
It said power was restored to Unison's Rotorua network at about 2.55pm and all customers on its network were restored by 3.10pm.
Unison said there was no damage to its assets, network or infrastructure as a result of the outage.
"Unison looks forward to Transpower sharing the results of its investigation into this incident so our organisations can collectively work to prevent similar incidents in future."
