Every year, electrical fires cause billions in property damage and pose serious risks to occupants.
But many building owners don't fully understand what makes Class C fires unique and dangerous.
Unlike other fire types that can be extinguished with water, Class C fires involving energized electrical equipment require specialized knowledge and suppression methods to prevent further damage and potential electrocution hazards.
For building owners and project managers, understanding Class C fires is essential for protecting property investments, ensuring occupant safety, and maintaining compliance with fire safety regulations.
A Class C fire is defined as a fire involving energized electrical equipment where the electrical current poses an additional hazard beyond the flames themselves.
These fires are particularly dangerous because they combine the already destructive power of fire with the risk of electrical shock, making traditional firefighting methods not only ineffective but more dangerous.
According to the National Fire Protection Association, there are an estimated 33,470 commercial electrical fires each year in the United States, killing nearly 45 people and costing around $1.36 billion in direct property damage, making them a significant concern for building owners and property managers.
Class C fires are defined by the presence of live electrical current, setting them apart from other fire types.
When electrical equipment malfunctions, it can generate enough heat to ignite nearby combustible materials while maintaining an electrical charge. This charge makes water-based suppression more hazardous, as water acts as a conduit for electricity, potentially allowing the fire to spread further.
The electrical component means that simply removing the fuel source may not be sufficient—the power source must be addressed to prevent re-ignition and eliminate the electrocution risk.
Here’s a breakdown of the different types and classifications of fires:
Understanding these distinctions is crucial because using the wrong extinguishing agent can worsen the situation or create additional hazards.
This understanding directly impacts emergency response procedures, equipment selection, and overall fire safety planning for commercial properties.
Class C fires typically originate from electrical equipment that has become energized beyond safe operating parameters.
The most common causes in commercial settings include:
Over 22% of non-residential fires are electrical fires, caused by short circuits or wiring problems. Overloaded circuits happen when electrical demand exceeds the circuit’s capacity, increasing the risk of overheating and fire. This is particularly common in commercial buildings where electrical demands may exceed the original system design.
Faulty wiring, whether due to age, poor installation, or damage, creates resistance points that generate heat and can produce dangerous electrical arcs.
Electrical equipment malfunctions are another significant source of Class C fires in commercial settings. Outdated equipment, frayed or faulty wiring, and environmental factors like dust, airborne contaminants, or extreme humidity create perfect conditions for arcing and short circuits.
Electrical arcing occurs when a current jumps across a gap between conductive materials, reaching temperatures of over 10,000 degrees Fahrenheit and combusting flammable materials.
Electrical fires can be especially dangerous and costly when they occur in spaces with large volumes of specialist equipment, like substations, server rooms, data centers, or manufacturing facilities.
We touched on this briefly earlier, but the presence of live electrical currents makes Class C fire suppression unique.
Traditional water-based suppression methods become dangerous rather than helpful because water conducts electricity, creating potential pathways for electrical current that can electrocute firefighters and building occupants while potentially spreading the fire to other areas.
To help, there are specific Class C portable fire extinguishers. These devices use non-conductive extinguishing agents like carbon dioxide (CO2) or dry chemical extinguisher that uses powders to displace oxygen, suffocating the fire.
Plus, CO2 is a clean agent that leaves no residue, which makes it ideal for environments with expensive electronic, medical, or manufacturing equipment.
The placement strategy for Class C extinguishers depends on the specific electrical hazards present in the building.
According to NFPA standards, Class C fire extinguishers should be sized and located based on the anticipated Class A or B hazard, since Class C fires are simply A or B fires that involve electrical equipment. This means that the travel distance for a Class C fire extinguisher is determined by the A or B hazards present.
For comprehensive fire protection guidance, building owners should consult Impact Fire's ultimate guide to fire extinguishers to understand the full range of extinguisher options and their appropriate applications.
Commercial buildings require careful consideration of extinguisher placement to ensure compliance with safety codes. The maximum travel distance to a fire extinguisher should not exceed:
Building owners must also ensure that extinguishers are mounted, labeled, and readily accessible in designated locations. Regular maintenance requirements include monthly visual inspections and annual maintenance checks to ensure optimal performance during emergency situations.
Beyond having proper suppression equipment, preventing Class C fires requires a proactive approach to electrical system maintenance and hazard identification.
Regular electrical inspections form the foundation of Class C fire prevention. Commercial buildings should schedule annual electrical inspections at a minimum to maintain code compliance. These inspections should assess wiring condition, circuit breaker functionality, and overall electrical system health.
Implementing routine equipment maintenance and environmental controls is essential for reducing fire risk.
Outdated equipment, frayed wiring, and environmental factors like dust, airborne contaminants, or extreme humidity create perfect conditions for electrical fires. Building owners should implement regular inspections of electrical panels, outlets, and connections to detect loose wiring, corrosion, or overloaded circuits before they become hazards.
Staff training and awareness programs are equally important for fire prevention. Companies should provide electrical safety training to help employees recognize warning signs like frequent circuit breaker trips, flickering lights, unusual odors, or sounds. Early detection of these warning signs allows for prompt professional intervention before dangerous conditions develop.
Understanding Class C fires is essential for building owners and project managers committed to protecting their properties and occupants. These electrical fires present unique challenges that require specialized knowledge, appropriate suppression equipment, and proactive prevention strategies to address effectively.
Building owners should partner with qualified fire protection professionals who understand the complexities of Class C fire risks and can provide comprehensive solutions tailored to their specific commercial environments.
Professional fire protection services can assess your building's unique electrical hazards, recommend appropriate suppression systems, and develop maintenance protocols that keep your property safe and compliant with safety codes.
Contact the fire safety experts at Impact Fire to develop a comprehensive fire protection strategy for your commercial property.