About 4,600 Nova Scotia Power customers lost electricity this morning.

Three schools closed because of the outage. Halifax Regional School Board said the outage forced the cancellation of East St. Margaret's Elementary, Five Bridges Junior High and St. Margaret's Bay Elementary.

The outage in the St. Margarets Bay area affects people from Tantallon to Peggys Cove. They lost power at midnight and were not fully reconnected until late Friday morning. 

"There is a high-voltage circuit breaker in the sub-station in St. Margarets Bay in the hydro facility," said spokeswoman Beverly Ware early Friday.

"That breaker failed in the substation last night, and it's the link between the substation and the transmission line in the area, and that's why so many customers have been affected."