More than 500 homes and businesses are without power in Dublin city.
Most of the outages are in Drumcondra, with supply expected to be restored later this morning.
Two other faults are affecting ESB customers on Leeson Street and Pembroke.
There are also faults affected over 100 premises in Ballinrobe, Co Mayo and Carrigallen, Co Leitrim.
There are smaller outages this morning in Ballinderry, near Mullingar and in Edenderry, Co Offaly, according to the ESB.