ESB Networks has been dealing with several incidents where live copper overhead lines have been stolen by third parties.
These criminals are also stealing copper earthing conductor from high voltage substations all over the country, Gardai said.
Not only are the perpetrators of these crimes putting their lives at risk, they are also endangering the lives of members of the public by leaving potentially unsafe live electrical network after them and interrupting supply to critical services, the ESB and Gardai said.
There is extreme danger of severe injury or fatality when attempting to steal live electricity lines or metal from ESB Networks high voltage substations.
The thefts, which have occurred across the country, can result in loss of electricity supply to customers in the areas targeted by thieves. It also causes significant the inconvenience caused to local residents while the repair works are carried out by ESB Network crews.
This has an impact on domestic and commercial customers. ESB Networks is particularly concerned that the theft of live electrical equipment can have a severe impact on vulnerable customers.
"We apologise to customers that may experience sudden and unexpected loss of electricity supply due to this theft," a ESB spokesperson said today.
"This illegal activity results in significant costs to ESB Networks in repairing the damaged network. These costs are ultimately borne by all electricity customers. The events of recent days highlight the importance of public awareness of this illegal activity.
"ESB Networks is actively working with An Garda Siochana to tackle this activity, and are pursuing every feasible means of protecting the electricity network. The public have an important part to play in helping put a stop to this type of theft.
"We would appreciate the assistance of the public who should call our 24-hour emergency hotline on 1850 372 999 and the Gardaí at 999/112 if they notice suspicious activity near our network.
"We appeal particularly to members of the rural and farming communities whose land is being trespassed upon, and damaged by these thieves to be vigilant and to contact us immediately if they believe that there is any suspicious activity taking place close to electricity networks on their land.
Gardai are warning the public not to approach either the thieves or the electrical network as there may be live electrical network left in an unsafe condition by the thieves.
ESB Networks is also engaging with other utilities and government departments and agencies to bring about a co-ordinated and organised response across all sectors to this illegal activity.
Three men appeared before The Criminal Courts of Justice this morning charged in connection with the theft of overhead cable belonging to the ESB.
Gardaí attached to the Drugs and Organised Crime Bureau assisted by local Gardaí from Kildare and the Garda Air Support Unit carried out an arrest operation in Rathdangan, County Kildare in the early hours of the yesterday morning.
They were arrested after the raid at 4.40am and were subsequently detained at Naas and Leixlip Garda Stations.
Two cars were also seized in relation to this operation.
"Investigations have been carried into the large scale organised theft of live electrical cable throughout the Country over the past number of months," a Gardai spokesperson said.
"The modus operandi of the group involved was to climb electrical poles and cut large amounts of copper wire over a period of several hours.
This has resulted in power outages to large sections of the country; it presented a serious danger to the public and resulted in millions of euros worth of damage to ESB power lines.
"To-date this year 142 kilometres of power lines have been stolen at a replacement cost of €4.6million."