KITCHENER -- Hydro One reports that power has been restored after 1,500 customers were left in the dark early Friday morning.

Firefighters were called to the fire at a Hydro One substation on County Road 18 in Centre Wellington at 3:15 a.m.

Fire officials say that 17 firefighters responded to the call but had to wait for hydro crews to isolate the power before they were able to extinguish the fire.

Deputy Fire Chief Jonathan Karn said that the fire had been extinguished just before 6 a.m., but power had been affected for areas of Salem, Fergus and Elora serviced by Hydro One.

Power was fully restored to customers just after 10 a.m., according to Hydro One.

Hydro crews remained on scene Friday to continue repairs and determine a possible cause.