More than 1,500 homes and businesses were left without power after a substation cable fault.
Electricity North West said 1,541 properties, including many in the Huncoat and Altham area, were without electricity from shortly before 12.30pm on Monday.
A company spokesperson said: “We have got about 1,000 back on, there are 526 still off at the moment.
“Engineers arrived within 10 minutes and found there was a faulty cable within an electricity substation on the Moorfield Industrial Estate.
“We have got engineers there now and they have estimated that everyone will be back on by 4.30pm.”
Huncoat Primary School was one of the buildings affected by the power cut.
In a post on Facebook, the school said: “We are experiencing a power cut in the area.
"Dinners have been served and school is open as normal. Our telephone lines are currently down.”
Electricity North West has advised people to call 105 to find out more information and to receive further updates.
It is the second major power cut to hit Hyndburn in less than a week after nearly 600 homes in the Sydney Street area of Accrington were affected for around three hours on the evening of June 14 due to a transformer fault at a local substation.