9 Common Electrical Fire Causes

Electrical fires are typically started by faulty wiring, overloaded circuits, malfunctioning appliances, or improper use of extension cords and space heaters.

These problems create heat, sparks, or arcing that can ignite nearby combustible materials and lead to a fast-spreading fire.

Our article explains what an electrical fire is, the nine most common electrical fire causes, how to recognize the early warning signs, and clear, practical steps you can take to prevent electrical fires in homes and workplaces.

What is an Electrical Fire?

An electrical fire begins when an electrical fault, such as overheating, arcing, or a short circuit, creates enough heat to ignite nearby materials like insulation, paper, fabrics, or wood.

Electrical fires can be particularly hazardous because they may start inside walls or behind appliances where smoke and heat go unnoticed until the fire has grown.

Electrical systems are a common ignition source and are linked to tens of thousands of fires each year.

What Causes an Electrical Fire?

Below are the nine most common electrical fire causes, explained in plain language so you can recognize risks and address them.

1. Faulty Outlets

Faulty Outlets

Outlets that are loose, cracked, or discolored can produce poor connections and arcing i.e. tiny sparks that generate intense heat.

A plug that feels loose in the socket or an outlet that looks charred are strong warning signs.

If you notice any of those signs, stop using the outlet and get a qualified electrician to inspect it.

2. Overloaded Circuits

Overloaded Circuits

When too many appliances draw power on the same circuit, wires and devices can overheat.

This is especially common in older homes that were not wired to code to handle today’s devices (air conditioners, large TVs, chargers, etc.).

Repeated tripping of a breaker or frequent blown fuses are signs a circuit is overloaded and needs attention.

3. Faulty Appliances

Faulty Appliances

Appliances with frayed cords, damaged plugs, or internal faults may overheat or short-circuit.

The risk increases when an appliance is used beyond its intended purpose or left running unattended for long periods.

When an appliance shows signs of smoke, sparks, or a burning smell, unplug it and have it inspected or replaced.

4. Faulty Wiring

Faulty Wiring

Old, degraded, or improperly installed wiring is a principal cause of electrical fires.

Insulation that is worn or chewed by rodents, loose connections at junctions, and wiring that cannot carry modern electrical loads can all lead to overheating and arcing.

If your home is several decades old and has never had an electrical inspection, consider having a licensed electrician evaluate the system.

5. Overloaded Light Fixtures

Overloaded Light Fixtures

Using bulbs with higher wattage than a fixture supports or placing flammable materials too close to lamps can cause fixtures and shades to overheat and ignite.

Always use the maximum wattage specified on the fixture and prefer LED bulbs, which operate at a cooler temperature and reduce heat risk.

6. Extension Cords

Extension Cords

Extension cords are meant to be temporary.

Running large appliances on extension cords, routing cords under carpets, or using damaged cords increases the risk of overheating and electrical fires.

If you rely on extension cords regularly, the safer long-term solution is to install additional wall outlets.

7. Portable Space Heaters

Portable Space Heaters

Space heaters are a leading source of electrical fires when placed too close to curtains, bedding, furniture, or papers.

Heaters with exposed coils are particularly risky.

Keep a three-foot clearance around any space heater, use models with tip-over and overheat protection, and always switch them off when leaving the room or going to sleep.

8. Ungrounded Plugs

Ungrounded Plugs

Three-prong plugs include a grounding prong that directs fault current safely to ground.

Removing the prong to fit a two-slot outlet eliminates that protection and increases fire and shock risk.

Never alter plugs, and instead have properly grounded receptacles installed by a licensed electrician.

9. Flammable Materials Near Fixtures

Flammable Materials Near Fixtures

Even a small electrical fault can ignite nearby flammable items like paper, curtains, clothing, or cardboard.

Lamps, chargers, and appliances should be positioned so combustible materials cannot drift or be placed close to heat sources.

Regular housekeeping to remove clutter reduces combustible materials and gives electrical faults less to burn.

Signs of an Electrical Fire

Early fire detection can prevent a small electrical problem from becoming a major blaze. Watch for these telltale signs:

  • A strong burning or plastic-like odor, especially near walls, outlets, or appliances.
  • Sparks, flickering lights, or outlets that feel warm to the touch.
  • Breakers that trip frequently or fuses that blow repeatedly.
  • Discolored, scorched, or sizzling outlets or switch covers. 

If you notice any of these signs, cut power to the affected area and call a licensed electrician.

If a fire is already present or smoke is spreading, evacuate immediately and call emergency services.

How to Prevent Electrical Fires

Electrical Inspection

Prevention centers around inspection, sensible use of appliances, and following electrical safety best practices.

Below are practical measures you can take:

Regular Wiring Inspection

Have a licensed electrician inspect your home’s wiring every few years, and more often for older properties.

Inspections identify worn insulation, overloaded circuits, and unsafe modifications before they become hazards.

Upgrade Your Electrical Panel

If your panel is outdated or cannot cope with modern loads, upgrade it to a newer model.

Modern panels, combined with devices like Arc Fault Circuit Interrupters (AFCIs), reduce fire risk by detecting dangerous arcing and shutting off power before ignition.

Avoid DIY Electrical Work

Electrical work should be done by licensed professionals.

Improper wiring, incorrect connections, and noncompliant installations are common causes of later fires.

Even seemingly simple tasks, like replacing an outlet, can be risky without the right knowledge and tools.

Avoid Overloading Electrical Outlets

Distribute high-draw appliances across different circuits and do not use power strips for large appliances.

If you are frequently tripping breakers, have an electrician evaluate and balance your loads or install additional circuits.

Use the Correct Lightbulbs

Match bulb wattage to the fixture rating and choose LED bulbs for lower heat output.

Inspect lampshades and fixtures for discoloration or damage and replace components as needed.

Use Space Heaters Safely

Choose heaters with built-in safety features and never place them on soft surfaces.

Keep them away from flammables and never leave them unattended.

Install Smoke Detectors

Working smoke alarms give the earliest warning.

Install alarms on every level and in or near sleeping areas, and test them monthly.

Interconnected alarms are best because all units sound if any one detects smoke. 

Get Fire Extinguishers and Blankets

For very small electrical fires, an ABC-rated or multi-purpose extinguisher may be effective, but only if you are trained and it is safe to do so.

Never use water on electrical fires; water conducts electricity and can cause shock and spread the hazard.

For small cooking or clothing fires, a fire blanket or baking soda can help smother flames.

Devise a Fire Emergency Plan

Have an evacuation plan, clear exits, and a meeting point outside the home.

Teach all household members how to shut off main power and call emergency services.

Practice escape routes regularly.

Key Takeaways

Electrical fires are caused by predictable and preventable issues: faulty wiring, overloaded circuits, damaged appliances, misuse of extension cords, and unsafe heating or lighting practices.

Recognize the warning signs like burning smells, warm outlets, flickering lights, and act promptly by cutting power and contacting a professional.

Regular inspections, sensible appliance use, modern safety devices such as AFCIs, and working smoke alarms dramatically reduce risk.

Staying informed and taking straightforward safety steps is the single most effective way to protect people and property from electrical fires.

Danger at the distribution point, with Gavin Parker

Gavin Parker shares critical lessons from his decades of experience responding to dangerous and disruptive substation fires across the electrical network 

When a fire broke out at an electricity substation in Hayes on 22 March 2025, it triggered a major shutdown at Heathrow Airport. The airport remained closed for 18 hours, disrupting flights for around 200,000 passengers. Although Heathrow has three substations and emergency back-up systems, delays in switching power supplies exposed weaknesses in its operational resilience. 

Electrical substations, like the one involved in the Heathrow incident, are a critical part of the power distribution network. Fires at these sites pose a range of risks—high-voltage equipment, potential explosions, hazardous smoke, and environmental contamination—all of which demand a carefully coordinated and safety-driven emergency response. 

To better understand how fire services prepare for and respond to substation fires, Gavin Parker, an expert in electrical infrastructure and emergency planning, shares insights that detail the unique hazards of these incidents and outline key operational considerations for firefighters and incident commanders. 

Transmission and distribution network 

There are many types of electrical substations that form part of the transmission and distribution network, including transmission, distribution, converter and collector. Transformer yards (switchyards) may be situated within a substation or at a power station. 

Substation fire hazards 

Substation fires present numerous risks. High-voltage equipment can arc and electrocute responders if approached improperly, including through indirect contact with conductive materials, which can be fatal. Transformer failures may lead to explosions, projecting debris and igniting nearby materials.  

Burning electrical insulation and cooling oils can release hazardous fumes, creating toxic smoke hazards. Heat and explosions may also damage steel and concrete supports, leading to structural instability and potential collapse. 

Apart from risks to safety, fires in substations can have severe consequences, disrupting power supply and causing significant financial and environmental damage. Key impacts include: 

Power disruptions: Fires can lead to power outages that disrupt power generation and supply to residential, commercial, and industrial operations, including manufacturing processes. Prolonged outages can halt critical systems, causing disruption, production delays and financial losses. 

Property damage: Intense heat and flames can severely damage infrastructure and electrical equipment. Repair and replacement costs can be substantial, often requiring extended downtime. 

Environmental impact: Transformer fires at substations may release insulating oil and other hazardous substances, contaminating soil and water. Polychlorinated biphenyls (PCBs), historically used in older transformers, pose additional environmental and health risks if released. 

Pre-incident planning 

Fire services should engage in pre-incident planning to enhance preparedness. This includes conducting site visits with utility providers to identify access procedures, specialist on-site or remote isolation procedures, and hazardous zones. Personnel should be trained in electrical safety, the use of Thermal Imaging Cameras (TICs), and specialised suppression tactics.  

Clear response procedures should be established, including a designated staging area for assembly before entry.

Gavin Parker

Fire services should also maintain up-to-date contact information for both business and after-hours emergencies with power companies to enable timely access and de-energisation of affected equipment. 

Utility and distribution companies play a crucial role in substation fire incidents. Firefighters should not enter an electrical substation unless accompanied by a representative from the power authority or distribution company. Entering a high-voltage area and commencing operations before confirmation of power isolation can be fatal. Maintaining direct communication with utility representatives is essential to receive real-time updates during the incident. 

Fire suppression tactics 

Substation fires require a strategic approach and dynamic risk assessment to minimise risks while effectively controlling the fire. 

Monitor burning from a safe distance: Burning electrical equipment will, in most cases, have to be replaced. Contact the power distribution authority and wait for them to arrive. Under no circumstances should firefighters enter a substation before power distribution company personnel arrive. 

Community warnings and isolation of the area: Issue community warnings/information for smoke and traffic restrictions. Liaise with police and local authorities for a traffic management plan. Keep unauthorized persons away. Consider smoke plume modelling if available to assist with planning and community warnings. 

Be alert to the risk of transformer explosions, smoke hazards and oil releases: Stay upwind and consider initial downwind evacuation and warnings.  

Defensive positioning: Firefighters should maintain a safe distance and use non-conductive materials and broken hose streams to de-energised equipment for suppression. 

Co-ordinated suppression plans: The fire service incident controller should liaise with site specialists such as a site Emergency Service Liaison Officer (ESLO or Emergency Service  Officer), Environmental Protection Authority (EPA) representatives and other stakeholders to formulate planning. 

Use of dry chemical agents: Class C extinguishing agents, such as dry powders or CO2, are preferred for energised electrical fires. 

Foam or water application: When transformers contain oil, foam or water may be used after confirmation of de-energisation. 

Cooling exposed equipment: Applying water in a fog (semi-fog) pattern from a safe distance can prevent adjacent equipment from overheating and fire spread. 

Monitor and manage contaminated water and oil runoff: Monitor for off-site release, utilise runoff management procedures such as bunding, containment, or direct it away from water catchments. 

Monitoring fire conditions to ensure extinguishment: Following suppression, the site may have to be monitored to ensure complete extinguishment; traditional overhaul procedures may not be possible, due to the nature of the site and risks. 

Once the fire is controlled, firefighters should monitor for re-ignition, as smouldering insulation or oil residues may reignite.  

Conclusion 

Substation fires demand a highly coordinated, safety-conscious approach. Fire services must emphasise pre-incident planning, specialised training, and collaboration with utility providers to ensure safe and effective incident resolution. 

Gavin Parker

The incident at Heathrow highlights how a single point of failure at a substation can have wide-reaching consequences beyond the immediate fireground. Effective response plans, developed in partnership with utility companies, are essential not only for firefighter safety but also for minimising disruption to critical infrastructure. 

This article was originally published in the May 2025 Edition of International Fire & Safety Journal. To read your FREE copy, click here