A San Diego Gas & Electric substation exploded into flames Thursday night near Bonita.
It's not yet clear if power could be affected by the fire at the substation in San Miguel Ranch.
The transformer is located near the State Route 125 and State Route 54.
A lot of people heard a blast around 11 p.m. Those calling 911 told officials they heard something like a huge explosion then flames erupted.
The fire lasted for almost five hours.
Heartland firefighters say blazes like this one are unusual.
It takes more to knock them down because they have to use foam instead of water.