Repair crews have come under attack while at work

The most recent attacks took place in the Lisburn Road and Holywood Road areas of the city.

In one incident, an employee was attacked by a gang of more than 30 youths while a cable worker suffered a broken arm after being attacked with missiles.

Last year, a two-man repair team was threatened at gunpoint.

The firm does not believe any of the incidents are paramilitary related.

NIE said that if its staff have to leave repair sites, it will not only delay the restoration of power, but could result in a wider loss of supplies if a substation has to be shut off because of exposed cables.

Spokesman Robin Greer said: "These deplorable attacks on workers trying to do their job means we are left with a choice between the safety of our staff, the safety of local residents and having to disconnect areas from the grid to ensure damaged cables are not left live.

"We cannot ask staff to stay at the scene of a fault if they are under threat."

NIE warned the threat had been heightened with the longer evenings, leading to an increase in vandalism that causes power cuts.

Mr Greer added: "We are therefore issuing this appeal to community representatives and parents to use their influence to allow our workers to do their job for the benefit of the community."