Maritime Electric has determined the cause of an electricity outage that caused about 28,000 customers to lose power Monday afternoon.

Workers ran into trouble while installing a transformer at the Charlottetown plant. Customers in parts of Charlottetown and Cornwall, and in all areas of the province east of the capital, lost electricity.

The power went out at about 2:05 p.m. and power was restored by 3:30 p.m. to all affected customers.

The utility also reported problems with brownouts Monday morning. It said trees rubbing against main power lines were to blame.