Approximately 12,000 homes and businesses remain without power across the State following storms Isha and Jocelyn.
The areas most affected are predominantly in counties Donegal, Sligo, Leitrim, Mayo, Cavan and Longford.
During the worst stages of Storm Isha on Sunday evening, more than 235,000 customers were without power.
However, ESB Network said significant progress has been made over the last 48 hours.
Crews are working through faults on the low voltage network that have primarily affected single homes and small clusters of customers.
It said all available company and contractor resources have been deployed, with additional crews arriving from the UK on Wednesday evening.
More than 50 skilled personnel from the UK National Grid Electricity Distribution and UK Power Networks will be deployed in the worst-affected areas from Thursday morning.
ESB said it is important that any impacted customers who use electrically powered medical devices contact their healthcare professional to make alternative arrangements if necessary.
In a statement it added: “We again apologise for the disruption to family and commercial life this causes, and thank customers across the country, especially those who will be without power again overnight, for their patience as our crews work to safely restore power.”
Earlier on Wednesday, NIE Networks said power had been restored to more than 52,000 customers since Sunday evening in Northern Ireland.
However, 1,200 remained without power on Wednesday morning.
