Christchurch, Rangiora and Kaiapoi residents were asked to reduce electricity usage to minimise risk of power cuts this evening, and the request worked.

Transpower said that reductions in electricity use by residents along with quick work by local lines companies to switch off controllable loads such as hot water systems has helped avoid power cuts this evening.

The owner of the national electricity grid called for help from residents around 6pm this evening after unseasonably cold weather pushed up electricity demand while one of its transformers at the Islington substation was on a planned maintenance outage.

Transpower also worked with electricity lines companies MainPower and Orion to switch off controllable load such as hot water systems to reduce demand on the grid.

“Residents should not have noticed any impact from this as it was for a short time and hot water systems are regularly switched on and off to manage demand peaks.”

Peak demand started tapering off after 7pm and no power cuts were needed.

“Transpower has taken steps to prevent the issue from reoccurring until a transformer is returned to service later this week.”

In a statement it said “outages are necessary so that maintenance work can be done to prevent the risk of unplanned outages caused by equipment failing. They are typically scheduled outside of winter when demand is lower.”

If power cuts had been necessary, they would have been for a limited time as a last resort to keep the power grid secure and minimise the risk of cascade grid failure.

Grid failure would have resulted in outages affecting a significantly larger number of people for a much longer period.”