Bangor Hydro Electric Co. says copper wire's been stolen from one of its substations.

Utility crews finished making repairs from an earlier wire theft on Friday evening. When they returned Monday, work crews discovered the thieves had returned to steal the newly installed copper wire from the substation in its northern service territory.

Bangor Hydro safety officer John Greaves said the utility is working with the sheriff's department and state police to find the thieves.

Greaves said the thieves could be injured or killed by cutting the wires. Power lines and substations operate at up to 345,000 volts, which is 3,000 times that of outlets in a home.