Northern Powergrid has said it is working to switch customers without electricity on to another part of its network as it looks to restore energy to 810 customers.
Earlier this evening 2,000 premises were left without power following a problem with the cables or equipment supplying the area around Seaton Carew shortly before 7.30pm today.
It has since restored electricity to 1,358 addresses, with 810 still without power.
Those in the TS25 postcode have been affected by the issue.
Northern Powergrid has said it estimates those remaining properties suffering an issue should have their supply restored by 9pm.
A spokesman for the company, which distributes power to 3.9 million homes and businesses across the region, said: "We are currently working hard to restore your power however we are unable to provide an accurate restoration time.
"Please call us on 105 if you have any specific questions."