Some heaters, hot water systems and streetlights may be out of action in parts of Wairarapa after a fire on Monday.
Powerco said it was alerted to the fire at its Greytown injection plant on Bidwills Cutting Road just before 10am.
No one was hurt in the fire and there were no power outages.
"An injection plant releases a signal along the electricity network and controls hot water, streetlights, night rate heaters," Powerco head of network operations Caz Haydon said.
While the plant was being repaired, streetlights in Greytown, Featherston and Martinborough would be turned on manually, with some areas potentially without lights because turning on each street light circuit manually took time.
Haydon said hot water would remain on, but night-rate hot water systems and night store heaters would not.
Customers who have chosen those services would have a lack of hot water tomorrow morning, she warned.
"Thanks to our customers for their understanding and patience while we repair the injection plant and restore services," Haydon said.
The fire is under investigation