Electrical Hazards for Fire and Rescue Departments Part II: Transformer Fires-Ground and Substation

1. Electrical Hazards for Fire and Rescue DepartmentsPart II: Transformer Fires-Ground and Substation

2. Electrical Hazards Transformers Hazards: High voltage (overhead & underground). Oil-filled switch gear, transformers. Toxic smoke and gases due to burning oil & insulating materials. Intense heat of a fire can collapse steel framework. Explosions from oil-filled equipment. Exploding glass & porcelain insulators. Falling wires.

3. Electrical Hazards In the rare case where the fire must be attacked and/or the equipment has not been de-energized, exercise extreme caution. Establish a safety zone, deny access, and evacuate area as needed. If the equipment is still energized, little can be done to extinguish the fire, as the oil will continue to re-ignite.

4. Electrical Hazards Some equipment, such as circuit switches and breakers, have porcelain housings that are pressurized. When involved in the fire and sprayed with water, the sudden temperature change may result in a violent explosion. Any electrical apparatus, transformer, or switch that has been on fire cannot be salvaged. If the fire will not endanger life or property, let it burn. Efforts should be directed at protecting surrounding property and awaiting arrival of the power company.

5. Case Study: Part II  Transformer Explosion Close Call (Please see PDF Handout)

6. Transformer Explosion Close Call

7. Transformer Explosion Close Call

11. Discussion Fire and Rescue Department (FRD) personnel are reminded to handle transformer events similar to hazardous material emergencies. Prior to arrival, identify the hazard, deny entry, cordon off the area, and request the utility company.  All FRD personnel are reminded to increase the safety awareness and to provide a risk analysis when responding to a transformer fire. The decision-making process must start prior to the arrival and a plan to mitigate the incident should be discussed. This includes the level of PPE for the identified hazard. Personnel should disembark the unit in structural personal protective equipment (PPE) including SCBA.  A firefighter was injured when the explosion occurred. The firefighter received a blast injury to the ear, was medically assessed at the scene, and transported to the hospital and treated and released to full duty. 

12. Discussion Handle switch box and transformer fires as HAZMAT calls. If you have to approach, use full PPE w/ SCBA. Position well away from the transformer. Deny entry and cordon off the area. Contact power company early in the incident.  If the transformer is on fire, do not apply water or other extinguishing agents, and do not approach it until it is confirmed de-energized.

13. Discussion Look/listen for scorching, leaking fluid, venting, smoke, and noises. When in doubt, secure the area, establish a safety zone, allow the power company to arrive and determine the safe and proper course of action. Efforts should be directed at protecting surrounding property, while awaiting the power company. Departments need to establish training programs and involve the local power company.