What Causes an Electrical Fire and How to Prevent Them?

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how to prevent electrical fires

Electrical fires are a significant concern in both residential and industrial settings. Understanding how these fires start and recognizing the warning signs can be the key to effective fire prevention and safety. This article focuses on the common causes of electrical fires, their warning signs, and the best practices for electrical fire prevention.

Key Takeaways

  • Electrical fires can be caused by various factors, including overloaded circuits and faulty appliances.
  • Recognizing warning signs of electrical fire like sparks and unusual smells can help prevent a fire from escalating.
  • Proper safety practices and adherence to building codes are essential in preventing electrical fires.

 

What is an Electrical Fire?

An electrical fire starts from electrical components or systems due to faults or failures that generate excessive heat. These fires are classified as Class C fires, involving energized electrical equipment. To understand electrical fires, it's helpful to grasp basic electrical concepts:

    • Voltage: The electrical potential difference that drives current flow
    • Current: The flow of electrical charge through a conductor
    • Resistance: The opposition to current flow in an electrical circuit

According to the U.S. Fire Administration, there were an estimated 26,100 residential building electrical malfunction fires in 2022, resulting in 185 deaths, 850 injuries, and approximately $1.5 billion in property loss.

Meanwhile, according to the National Fire Protection Association (NFPA) and the Electrical Safety Foundation International (ESFI), workplace electrical fire incidents from 2017 to 2022 show significant trends and statistics:

    • Between 2011 to 2022, there were 126 electrical fatalities in 2020, a 24% decrease from 2019, making it the lowest number since ESFI began compiling data. Contact with or exposure to electric current accounted for 2.6% of all workplace fatalities in 2020. The construction industry had the highest rate of fatal electrical injuries, followed by the mining industry.
    • Between 2011 to 2022, a total of 1,322 workplace electrical fatalities occurred, with 70% of these fatalities happening in non-electrical occupations. The construction industry consistently reported the highest number of electrical fatalities​
    • In 2020, there were 2,220 nonfatal electrical injuries involving days away from work, which was a 17% increase over 2019 and a return to 2017 levels.

Workers in installation, maintenance, and repair occupations experienced the highest number of nonfatal electrical injuries, followed by service occupations and construction and extraction occupations​.

How do electrical fires start?

Electrical fires begin when electrical currents generate excessive heat, igniting nearby combustible materials. Normally, when an electrical system operates, the heat produced is usually manageable and dissipated safely. However, when there is a fault or electrical failure, this heat can escalate to dangerous levels, leading to ignition. Common electrical components prone to failure include:

  1. Wiring
  2. Outlets
  3. Switches
  4. Appliances

Overloading occurs when too many devices draw power from a single circuit, exceeding its capacity. Short circuits happen when current flows along an unintended path, often due to damaged insulation.

 

Electrical Fires vs. Arc Flash

Electrical fires and arc flashes are distinct phenomena with different causes and consequences. Electrical fires typically start due to overheating from overloaded circuits, faulty wiring, or malfunctioning appliances, resulting in the ignition of surrounding materials and substantial property damage. In contrast, arc flashes involve a sudden release of electrical energy through the air due to equipment failure, human error, or short circuits, causing intense heat and light that can result in severe burns and equipment damage.

The primary risks of electrical fires include sustained burning leading to property damage and potential fatalities, while arc flashes pose immediate risks of severe burns, eye injuries, and blast effects. Preventing these incidents requires regular maintenance, proper training, and adherence to safety standards to mitigate the risks of both electrical fires and arc flashes effectively. These distinctions highlight the importance of targeted safety measures and protocols for different types of electrical hazards.

 

4 Common Causes of Electrical Fires

burning electrical wires

Understanding the common causes of electrical fires is crucial for implementing effective fire prevention strategies and ensuring safety in both residential and workplace environments:

Extension Cord Misuse

Overloading extension cords by plugging in too many devices or using them for high-wattage appliances can cause them to overheat, potentially leading to fires. Moreover, using extension cords as permanent wiring solutions instead of temporary fixes increases the risk of damage and overheating.

Overloaded Circuits

When too many devices draw power from the same circuit, the wiring can overheat, leading to the melting of insulation and potential ignition of surrounding materials. Circuit breakers are designed to prevent this by tripping when the current exceeds safe levels, but if they fail or are bypassed, the risk of fire increases.

Damaged Electrical Cords

Electrical cords that are frayed, cracked, or otherwise damaged can expose live electrical wires, leading to arcing and sparking. These sparks can ignite nearby flammable materials, causing a fire. Regular inspection and prompt replacement of damaged cords are essential to prevent such incidents.

Old or Faulty Appliances

Electrical appliances that are old or have internal faults can malfunction and overheat. Components within these appliances, such as motors and wiring, can fail, generating excessive heat and potentially sparking fires. Regular maintenance and timely replacement of faulty electrical appliances are critical for electrical fire safety.

 

Warning Signs of Electrical Fire

Recognizing the early warning signs of electrical fire can prevent severe damage and potentially save lives. Here are the key indicators to watch for:

  1. Sparks, Smoke, or Flames: If you see sparks coming from an outlet or electrical device, this is a clear sign of a serious problem that needs immediate attention. Smoke emanating from electrical outlets, appliances, or wiring indicates that the internal components are overheating and potentially burning. Visible flames are an urgent sign of an electrical fire and require immediate action to extinguish and prevent the fire from spreading.
  2. Discoloration or Melting of Wires or Outlets: Outlets or switches that appear discolored, charred, or melted indicate that excessive heat is being generated, which can lead to a fire. Electrical wiring insulation that appears scorched or melted is also a sign that the electrical current is causing overheating.
  3. Hot-to-Touch Electrical Components: Outlets, switches, or electrical appliances that are unusually warm or hot to the touch can indicate that they are overloaded or malfunctioning. This excessive heat can degrade insulation and components, increasing the risk of a fire.
  4. Buzzing, Crackling, or Popping Noises: Unusual sounds like buzzing and flickering lights, crackling, or popping from electrical outlets, switches, or appliances often signal that electrical arcing is occurring. These noises can indicate loose connections or damaged wiring, both of which can lead to fires.
  5. Burning Plastic or Rubber Smell: A distinct burning smell of plastic or rubber suggests that wiring insulation is overheating and melting. This odor is often one of the first signs of an electrical problem and should not be ignored.

 

How to Put Out an Electrical Fire

using fire extinguishers to put out electrical fire

Properly extinguishing an electrical fire requires understanding the specific nature of these fires and using appropriate methods to ensure safety. Here’s a detailed guide on how to effectively handle an electrical fire:

Using a Class C Fire Extinguishers

Class C Fire Extinguishers are specifically designed for electrical fires and contain non-conductive agents such as dry chemicals (e.g., monoammonium phosphate, sodium bicarbonate) or CO2 (carbon dioxide). This extinguisher for electrical fire works by disrupting the chemical reactions that sustain the fire without conducting electricity.

To use, pull the pin, aim the nozzle at the base of the fire, squeeze the handle, and sweep from side to side until the fire is out. Always maintain a safe distance and ensure the fire does not reignite.

pass fire extinguisher

Cutting Off the Power Source (if Safe to Do So)

If possible and safe, turn off the electrical power to the affected area. This can be done by switching off the circuit breaker or unplugging the device. Cutting off the power can prevent further electrical flow and reduce the risk of the fire spreading.
Do not attempt to turn off the power if the fire has already spread significantly or if accessing the power source puts you at risk of electrical shock or burns.

Smothering with a Fire Blanket or Baking Soda

Made from fire-resistant materials, fire blankets can be thrown over small electrical fires to smother the flames by cutting off the oxygen supply. For very small fires, baking soda can be used to extinguish the flames. Baking soda releases carbon dioxide when heated, which helps smother the fire.
Caution: Ensure the fire is small and manageable before attempting these methods. If the fire is spreading, it is safer to evacuate and call emergency services.

Call the Fire Department

Always call the fire department for assistance, even if you believe the fire is under control. Firefighters have the training and equipment to handle electrical fires safely and can ensure the fire does not reignite. After the fire is extinguished, professionals can inspect the area to determine the cause and ensure there are no lingering hazards.

What should you not do in an electrical fire?

Never use water to extinguish an electrical fire. Water conducts electricity and using it on an electrical fire can result in electric shock or worsen the fire by spreading the conductive liquid. Moreover, if the fire is large or spreading rapidly, do not attempt to fight it without appropriate fire-fighting equipment. Evacuate the area immediately and call the fire department. Personal safety should always be the priority.

 

Best Safety Practices to Avoid Electrical Fires

Implementing the best safety practices can significantly reduce the risk of electrical fires in both residential and workplace settings. Here are some key practices to follow:

Regular Electrical Inspections: Conduct a routine electrical inspection of all electrical systems and equipment to identify potential hazards before they become serious. Hire a qualified electrician to ensure thorough checks and necessary repairs are made to prevent electrical fires.

Proper Circuit Breaker Usage: Ensure circuit breakers are appropriately rated for their load and distribute devices across multiple circuits to avoid overloading. Test circuit breakers periodically to ensure they function correctly and replace any faulty units immediately.

Safe Appliance Usage: Follow manufacturer instructions for installing and using appliances, and avoid using damaged or old devices that may malfunction. Unplug appliances when not in use to prevent overheating and reduce fire risk.

Extension Cord Safety: Use extension cords rated for their load and avoid chaining multiple cords together. Treat extension cords as temporary solutions and install additional outlets to reduce reliance on them.

Outlet and Switch Maintenance: Regularly inspect outlets and switches for signs of wear, discoloration, or damage, and replace any that are malfunctioning. Use high-quality components to ensure reliability and reduce the risk of electrical fires.

GFCI Outlet Installation: Install Ground Fault Circuit Interrupter (GFCI) outlets in areas near water to protect against ground faults by shutting off power when faults are detected. GFCIs are essential in kitchens, bathrooms, and outdoor locations to enhance electrical safety​.

Electrical Safety Protocols: Provide regular safety training for employees and household members on safe electrical usage and maintenance. Establish clear electrical safety protocols and enforce them to prevent misuse and reduce fire risks.

Lockout Tagout (LOTO): Implement lockout tagout procedures to ensure electrical equipment is safely de-energized during maintenance or repair work. Train all personnel in LOTO procedures to prevent accidental energization and reduce the risk of electrical fires.

Emergency Procedures: Develop and communicate emergency procedures for electrical fires, including evacuation routes and emergency contact numbers. Conduct regular fire drills to ensure everyone knows how to respond, enhancing overall preparedness and safety​.

While following the best safety practices can significantly reduce the risk of electrical fires, it is essential to consult a licensed and experienced electrician for any electrical work, inspections, or repairs. Professional guidance ensures that all electrical systems meet safety standards and are installed and maintained correctly, minimizing the risk of fire and other electrical hazards.

 

Other Electrical Fire Prevention and Safety Tips

Electrical codes, such as the National Electrical Code (NEC) in the United States, provide guidelines for the safe installation and maintenance of electrical systems. Adhering to these codes helps prevent electrical fires, shocks, and other hazards by ensuring that electrical systems are properly designed and constructed.

At the same time, fire safety signs play a crucial role in workplace safety by providing clear instructions and information during emergencies. These signs help employees quickly locate fire extinguishers, emergency exits, and electrical shut-off points. Proper signage ensures that in the event of an electrical fire, workers can respond promptly and effectively, reducing the risk of injury and damage.

Lockout tagout practices also help prevent accidental energization, which can lead to electrical fires, shocks, and other injuries. Physically locking and tagging the equipment using LOTO devices to indicate it should not be used keeps maintenance personnel working safely. Proper training in LOTO procedures and adherence to these practices are vital for maintaining a safe working environment and preventing electrical incidents.

 

Electrical Fire FAQs

How is an electrical fire different from a regular fire?

An electrical fire originates from electrical components or systems due to faults such as short circuits or overloaded circuits, whereas regular fires can start from various sources like open flames, chemicals, or heat sources. Electrical fires often involve energized equipment, requiring specific extinguishing methods to avoid electric shock​.

How toxic is an electrical fire?

Electrical fires can be highly toxic due to the combustion of insulation, plastics, and other materials, releasing hazardous substances like carbon monoxide, dioxins, and furans. The smoke from these fires can be particularly harmful if inhaled, posing serious health risks.

Is it bad to put water on an electrical fire?

Yes, it is dangerous to use water on an electrical fire because water conducts electricity, which can cause electric shock or worsen the fire. Instead, use a Class C fire extinguisher for electrical fire or other recommended methods like baking soda for small fires.

Can an electrical fire start if the breaker is off?

An electrical fire cannot start from a circuit if the breaker is off because the electrical current is interrupted. However, fires can still start from residual heat or faults in other circuits that remain energized​.

Do electrical fires start right away?

Electrical fires often do not start immediately; they can smolder for hours or even days before igniting. This delayed reaction can be due to gradual overheating or arcing within electrical components​.

What do electrical fires smell like?

Electrical fires typically emit a distinct smell of burning plastic or rubber due to the combustion of wire insulation and other synthetic materials. This smell is often one of the first indicators of an electrical fire​.

How to put out electrical fire without extinguisher?

If you don't have a fire extinguisher, you can smother a small electrical fire with a fire blanket or baking soda, which can help extinguish the flames by cutting off the oxygen supply. Always turn off the power source if it's safe to do so and call the fire department for assistance.

The material provided in this article is for general information purposes only. It is not intended to replace professional/legal advice or substitute government regulations, industry standards, or other requirements specific to any business/activity. While we made sure to provide accurate and reliable information, we make no representation that the details or sources are up-to-date, complete or remain available. Readers should consult with an industrial safety expert, qualified professional, or attorney for any specific concerns and questions.

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Author: Herbert Post

Born in the Philadelphia area and raised in Houston by a family who was predominately employed in heavy manufacturing. Herb took a liking to factory processes and later safety compliance where he has spent the last 13 years facilitating best practices and teaching updated regulations. He is married with two children and a St Bernard named Jose. Herb is a self-described compliance geek. When he isn’t studying safety reports and regulatory interpretations he enjoys racquetball and watching his favorite football team, the Dallas Cowboys.