Almost 23,000 homes are still without power in Northern Ireland following the extreme weather conditions on Tuesday night.
The worst affected areas are Omagh, Derry, Coleraine and Ballymoney.
Sara McClintock from Northern Ireland Electricity said: 'Conditions on the ground remain difficult in many areas.
'We used helicopters yesterday to survey inaccessible parts of the network and to pinpoint where to send repair crews. These aerial surveys will continue today.
'Over 120 additional engineers and linesmen are arriving this morning from the Republic of Ireland and Great Britain.'
Meanwhile, an ESB spokesperson has said 250 households in border areas are still without power.