19,000 homes and business are without power this morning after new faults developed in Wexford, Limerick and Kerry last night.
ESB Networks said it hopes to clear the faults this morning.
"We're continuing to work as much as we possibly can … there are about 3,000 people working on this, and have been right the way through," said Customer Service Manager Paul Mulvaney.
"We'll continue until everybody is connected, obviously, and we'll have a lot back today."
He warned, however, that some individuals in "outlying areas" may not have power reconnected until the end of the week.