Around 2,500 people around Dublin's north inner city were left without electricity last night following a fire in an electrical sub-station.
A fault was identified at around 10pm at the Summerhill exchange.
Dublin Fire Brigade were called to the scene and extinguished the blaze. There were no injuries in the incident, but its cause was unclear.
An ESB spokesperson said most of those customers affected would have their electricity returned swiftly.
"There are a small number of people who may be without electricity until the morning," she said.
ESB crews were last night working on returning the sub-station to working order.