Four rolls of copper wire were taken from the Hydro One Transformer Station off Finch Dr. Monday evening.
Sarnia police say suspects entered the yard by cutting a hole in the fence.
A similar incident was investigated over the weekend at the site, however, nothing was taken.
Anyone with information about the theft or who comes upon someone trying to turn in quantities of number 4 copper wire as scrap metal, is asked to call Sarnia police or Crime Stoppers.
Police say not only did these thieves break the law, but placed their own lives in danger due to high voltage in the area.