Power went out for about 1,600 customers on Friday afternoon after, police said, vandals cut copper ground wires from the Basin Road substation.
Police say the suspects gained access by cutting a hole in the fence surrounding transformers.
The removal of the copper wire caused a wide spread power outage to businesses and homes along the US Rt. 13 and DE Rt. 141 corridor in New Castle.
A previous theft happened between 6:00 p.m. Thursday and 6:00 a.m. Friday at a substation on Newport Gap Pike in Wilmington. There, 100 feet of copper wire was removed. Police say it has a value of $300.
That same substation was hit by a copper theft back on August 7.
There have been no arrests made in these incidents.