The vandals broke into a switching site vandalising equipment and, at a second incident in the same area, cut down and burnt an electricity pole.
A spokesman for NIE said they could have been seriously injured or even killed while carrying out their attacks which caused two separate faults on the electricity network and left householders in the Ballykeel and Larne Road areas without electricity.
The incidents took place at around 9pm and NIE emergency repair teams responded immediately and restored power to the majority of customers within 30 minutes.
Final repairs to the network carried on throughout the night and remaining customers had their electricity supplies in the early hours of Wednesday morning.
Roy Coulter, Safety Manager at NIE, said: “As far as we can understand, the vandals broke into the switching site, damaging signage, interfering with equipment and breaking off locks with what appears to be a hatchet. They then carried on their rampage by cutting down an electricity pole. The pole had a live cable running up its centre.
“Thousands of volts of electricity run through this equipment and the cable every second so the risk of electrocution was extremely high. We cannot stress strongly enough the danger of this type of deliberate damage.
“Those involved should consider themselves lucky that they weren’t seriously injured or even killed,” he said.
NIE teams have re-secured the switching station, repaired the damage and have informed the PSNI of the incident. This is the third time that equipment in this area has been damaged.
Roy Coulter said: “This incident has caused great inconvenience to people in this area.
“We would appeal to all members of the local community to be extra vigilant and report any suspicious activity around NIE equipment on 08457 643 643 or to the PSNI.”
He added that, annually, NIE speaks to around 18,000 school children across Northern Ireland to warn them of the dangers of interfering with electrical equipment.