Use a CO2 fire extinguisher if the fire is small. Protect all circuits with a fuse or circuit breaker. Don't overload circuits or bypass the circuit protection. Electricity can be a potent fire source. Many farmers and others have lost a barn or house from old or defective wiring.
Overloaded wiring can be very dangerous.
It is safer and more efficient to install new circuits. Hazards Potential electrical fire hazards are everywhere. A build up of dust, trash and spider webs is an invitation for fire to start in the electrical system. Good housekeeping greatly reduces the odds for a fire. Unprotected light bulbs in work areas are another potential hazard.