Some Gardner customers experienced a brief power outage about 7:50 a.m. on June 15.
According to Gardner Electric, the outage happened when employees were inspecting and repairing equipment damaged during recent vandalism.
During the work, a relay failed and a substation transformer tripped off line, causing a three minute outage to part of the city.
Vandals damaged electronic equipment that controls one of the substation transformers at the Santa Fe Sub during a break-in on May 29.