Common Causes of Electrical Fires

December 12, 2019

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There are countless ways electrical fires can start. It’s important to be aware of what may cause electrical fires so you can prepare and prevent them when possible. According to the U.S. Fire Administration, between 2014 and 2016, there were more than 20,000 residential building electrical fires each year. Further, electrical fires can seriously damage commercial structures as well. Here is a guide to the most common causes of electrical fires and what warning signs to watch for at your own properties.


Wiring issues are one of the leading causes of electrical fires. There are many ways in which poor wiring could result in fires or even explosions.

Exposed wiring

Exposed wiring can cause connectivity issues and lead to a fire. When the electrons move through the live wire, they can jump and produce sparks. If there are dust particles or other debris in the air, which is common in most industrial settings, it can ignite and spread.

Wiring not up-to-code

It’s common for professionals to make mistakes when it comes to keeping up with the ever-changing National Fire Protection Association’s National Electric Code. Many professionals overcrowd wires, which is a major fire hazard because the wires could damage each other, resulting in exposed wiring.

Knob and tube wiring are other violations to look out for. While this was generally accepted as a safe method until the turn of the century, it’s now outdated and cannot keep up with modern electrical usage.

One more common issue to look out for is pairing new lights with old wires. This is a very easy thing to overlook, but the mistake can increase your risk of fires. Most older wires have a heat capacity of about 60 degrees Celsius, while newer lights average heat capacity of almost 90 degrees Celsius.

Defective wiring

When wiring is defective, it can cause wires to spark. If this were to happen near insulation, it could result in a substantial fire. More signs of defective wiring include flickering lights, constant circuit breaker tripping, shocks when touching appliances, and outlet sparking.

Defects may be the result of poor workmanship, lack of quality control, or rushed work. To locate and prevent defects, professionals should perform regular inspections during construction. If you notice a burning smell or overheating fixtures, these are signs of an issue as well.

Old and outdated wiring

Older wiring cannot handle the current electrical demands. The average person uses much more electricity today than they would have needed 50 years ago. Many rely on electricity not only to power lights but to run computers, charge phones, power their cars, and much more. Almost every modern appliance requires electricity. As such, it can be easy to overload your electrical wires. The wires may overheat and even spark onto surrounding materials, such as insulation, which can cause rapidly spreading fires.

Wiring with a deteriorating coating

When the coating on electrical wires begins to deteriorate, the wires become more susceptible to arcing. Arc flash can start fires, cause explosions, and result in injuries and even death of surrounding individuals. Make sure your wires have an intact coating and have the correct circuit amperage for usage.

Wires don’t match circuit amperage

When wiring doesn’t match the circuit amperage, excess heat can melt the wires, resulting in fires that easily spread to surrounding materials. The higher the amperage rating of your circuit, the larger your wires need to be.


When it comes to electrical fires, outlets are commonplace for them to originate. It’s important to pay attention to any problems you may have with your outlets. Be sure to install the correct type of outlet in the proper places and remember to use the outlets responsibly.


Outlets are only meant to handle so much. Plugging in multiple high voltage appliances to a singular outlet can cause it to fail, spark, or even melt entirely. When the amount of electricity demanded from an outlet exceeds its intended usage, it can generate heat in unpredictable and unmanageable amounts. This wears on the electrical wiring and can spark fires.

Extension cords

The original purpose of extension cords was to extend the usefulness of outlets, allowing users to position their appliances further away from the outlet. This was revolutionary, but there was never any intention for them to remain as permanent fixtures. If used properly and temporarily, and monitored regularly, extension cords are safe.

When overloaded or if it exceeds the electrical capacity of the extension cord, it can overheat and cause sparks, melting, and fires. It’s common to load the extension cord with the electrical capacity of the outlet, but it’s important to remember the cord may have different limitations. You should always double-check before using them.

Don’t run cords under carpets, through doorways, or under furniture to protect from further fire hazards. Additionally, limit outdoor usage to cords made specifically to endure outside conditions.


As unlikely as a static electricity fire may sound, many fires begin with static issues. Static electricity builds up when there is an imbalance between positive and negative charges in a single object. This builds up until it finds a method of discharge. Static is more common during the cold and dry winter season. That’s why in the wintertime you can often experience a minor shock when touching certain objects, such as metal or light switches. When static builds up a lot and needs to find a release, it can cause sparks and ignite dust particles, fumes, or other vaporous substances. This causes a fire that can easily spread to the rest of the air particles, insulation, and other objects.

To prevent static discharge fires, keep your space at a neutral level or humidity. You can also discharge the static electricity from items using a circuit.

Faulty appliances or equipment

The equipment used in your facility can potentially lead to electrical fires. Therefore, you must pay attention to certain issues and regularly check the equipment to aid in preventing electrical fires.

Greasy or dusty equipment

When equipment is overly greasy or dusty, any number of electrical problems can potentially light an explosion, which is devastating to workers and facilities. To prevent this issue, be sure to clean or wipe down your equipment and large appliances often. Electrical sparks by themselves typically aren’t devastating, but with the ability to ignite dust and grease, they can become extremely dangerous.

Faulty or unattended space heaters

Space heaters are a great way to supplement heat during colder months. However, when used improperly or left alone, they can start fires. Before using a space heater, make sure to read its label and familiarize yourself with the regulations. Inspect your heater’s plug for frayed or exposed wiring, as well as bent or otherwise disfigured prongs. If all the electrical faucets look up-to-par, test out the heater and keep it attended at all times. Keep it away from anything that could easily spark with heat, such as clothing, curtains, pipes, fumes, and dust particles.

Malfunctioning light fixtures

When lighting fixtures malfunction, it can result in arcing. Malfunctioning happens most often when lighting voltage exceeds the wire’s capability or when the wiring is faulty. To prevent this, make sure your lamp and lighting fixture wirings do not show signs of fraying, overheating, or breaking.

Important things to consider

When dealing with electrical fires, do not attempt to put them out with water. While many people’s first thought when witnessing a fire is to throw water on it, it’s important to remind your workers and building staff to avoid this at all costs. When electricity starts a fire, water can worsen the fire and put you and surrounding individuals at risk of electrocution.

If an electrical fire does happen, make sure to have an electrical fire investigation conducted to determine the exact cause. Professional investigators can aid you through the recovery process—from an injured individual filing a lawsuit to providing prevention methods for the future.

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