Linemen repairing one fault inadvertently found themselves with another yesterday.
On Tuesday evening around 1000 households in the western suburbs of Rotorua experienced power losses when a jumper failed. But when Unison workers went to fix it yesterday morning that led to further failures.
Unison customer relations spokesman Danny Gough said it was "almost the perfect storm".
"When we went out to do repairs on that fault we had to switch that load to other feeders to keep power on, but due to the cold morning and the extra demand it caused those other feeders to trip."
He said it took up to an hour to "smooth out". That meant some households were on part power and a few had no power for a short time. The faults were all repaired yesterday.
"We fully realise the impact it would have had on people and it's unfortunate it happened with the cold weather. As much as we proactively maintain our lines we can't predict something is going to fail."