That transformer caught fire just after 11 last night at the annex, which is off Hammond Rd.
Jail detention officers tried to put the fire out once it started, but the flames spread, so the Wichita Falls Fire Department responded.
The jail's power was out temporarily, but the power source was quickly switched to the emergency generator on site.
An electrical engineer who's working on the transformer was able to find the cause of the fire this morning.
Wichita County Sheriff David Duke says, "As the bull snake was actually eating on the birds, it made contact with all the heavy contacts in the box that sparked, caused a fire, set the grass on fire, and burned some of the contacts and the heavy duty wiring of this transformer."
Crews are working to fix the transformer and hope to have it repaired by tomorrow morning.
Duke says detention officers will be working in the jail to keep an eye on the inmates until the repairs are made.