The power outage, which occurred at 12pm today lasted until 3pm.
A spokesperson for ESB Networks apologised for the interruption to service.
"Our crews mobilised quickly to restore power to those affected.
"The ESB is continuing to investigate the cause of the power outage.
"We apologise for the inconvenience caused," the spokesperson said.
A huge number of people working from home, combined with children using online services for study and play, has led to an increase of up to 30%.
Paul Connell, CEO of Pure Telecom, said the surge in demand has been astonishing.
"The demand on the network has been astonishingly high," he said and reported a nationwide impact on the network.
"There are maybe 20% or 30% more people using the network."