Electrical fires: causes, prevention and protection systems
The presence of electrical installations in virtually all critical building systems makes electrical risk a decisive factor within any fire protection strategy. In industrial buildings, commercial properties, logistics centres or technical rooms, an incident of this nature can compromise fire compartmentation, evacuation, operational continuity and emergency response.
For this reason, electrical fire safety must be addressed from a comprehensive technical perspective: risk control during the design phase, preventive maintenance, early detection, suitable extinguishing systems, compartmentation and smoke control. This approach reduces the likelihood of fire development and limits its consequences for people, property and installations.
What will you learn in this article?
- You will learn how to identify an electrical fire
- You will discover the main causes of electrical fires
- You will learn which systems are most suitable for preventing and extinguishing a fire
What is an electrical fire?
An electrical fire is a fire in which electrical energy acts as the ignition source. The process may begin as a result of heat generation, an electrical arc, a spark, localised overheating or an insulation fault in an installation, device, electrical panel, cable route, battery, UPS, transformer or mains-powered machinery.
In these scenarios, the analysis must distinguish between the origin of the fire, the presence of electrical voltage during the intervention, and the construction elements or combustible materials that may contribute to its spread.
Why electrical fires are particularly dangerous
Their hazardous nature is associated with three factors: ignition in concealed areas, the possible presence of live electrical equipment during the emergency, and smoke generation in technical spaces or service routes. Suspended ceilings, service shafts, cable trays and electrical panel enclosures can delay identification of the seat of the fire.
Difference between an electrical fault and a fire involving live electrical equipment
An electrical fault is a functional or safety-related anomaly: overcurrent, leakage current, arcing, insulation failure, loose connection or abnormal heating. A fire involving live electrical equipment is an emergency scenario in which energised equipment, conductors or electrical panels are present. This distinction affects the isolation of the power supply, the selection of the extinguishing agent and the safety of emergency personnel.
How to identify a potential electrical fire
Identifying an electrical fire can be complex, as it often starts in concealed areas such as walls or ceilings where electrical wiring is installed. Common warning signs of an electrical fire include the following.
Smell of burning or melted plastic
The smell of burnt insulation, resin, PVC, rubber or melted plastic may indicate abnormal heating in conductors, terminals, terminal blocks, enclosures or electrical equipment.
Sparks, flames or unusual noises in the installation
Sparks, visible arcs, crackling, buzzing or unusual vibrations in electrical panels, cable routes or machinery must be treated as warning signs. Intervention must be restricted to qualified personnel.
Power outages, overheating or repeated tripping of protective devices
Repeated tripping of circuit breakers, residual-current devices or fuses, voltage drops, hot enclosures or the frequent resetting of protective devices may indicate an overload, current leakage, insulation failure or component deterioration.
Hot spots detected by thermographic inspection
Infrared thermography makes it possible to identify overheating in busbars, terminals, connections, protective devices, transformers, variable-frequency drives, motors and power equipment. It is a predictive maintenance tool suitable for installations with significant electrical loads.
Main causes of electrical fires
The list of causes that can lead to this type of fire is extensive, but some of the most common are as follows:
Overloads in circuits, electrical panels or equipment
An overload occurs when electrical demand exceeds the designed capacity of the circuit, equipment or protective device. If this condition persists, the temperature of conductors, connections and enclosures increases.
Damaged, incorrectly sized or deteriorated cables
Ageing insulation, an insufficient conductor cross-section, mechanical damage or exposure to heat, moisture or chemicals can reduce wiring safety and contribute to short circuits or localised overheating.
Defective connections and loose contacts
Incorrect tightening torque, a loose terminal, oxidation or connection degradation creates contact resistance. The resulting thermal effect may reach temperatures high enough to ignite nearby materials.
Lack of preventive electrical maintenance
The absence of periodic inspections prevents the detection of overheating, defective protective devices, dirt accumulation, corrosion, mechanical looseness or the deterioration of electrical components.
Accumulation of dust, dirt or moisture in electrical installations
Dust can act as a combustible load. Moisture contributes to leakage currents, corrosion and loss of insulation. In industrial environments, the presence of airborne particles requires particular attention in electrical panels, cable trays and technical rooms.
Industrial machinery, batteries and high-consumption electrical equipment
Motors, chargers, lithium batteries, UPS systems, variable-frequency drives, substations and process machinery contain high energy densities. Their control must be integrated into both the maintenance plan and the fire protection plan.
In these environments, wiring and its insulation systems must also be considered critical elements. According to NFPA data on fires in industrial and manufacturing properties, electrical wire or cable insulation fires accounted for 11% of the total direct property damage recorded in these facilities in 2023.
Risks of electrical fires in industrial buildings and commercial properties
Electrical fires can have significant consequences in buildings with high levels of technical, operational or commercial activity. Their impact depends not only on the point of origin, but also on the building configuration, the materials present, the installations affected and the ability to limit the spread of fire and smoke.
Spread of fire and smoke through concealed areas
Service penetrations, shafts, suspended ceilings, cable trays and technical voids can facilitate the spread of fire or smoke between compartments. Fire compartmentation in industrial buildings must take these routes into account from the design stage.
Damage to machinery, goods and critical installations
An electrical fire can affect main switchboards, production lines, HVAC systems, control equipment, servers, stored goods, safety systems and structural elements located close to the seat of the fire.
Business interruption and loss of operational continuity
In industrial, logistics or commercial environments, electrical damage may interrupt processes, render production areas unavailable, cause loss of service, affect critical supplies and require a technical inspection before operations can resume.
Risks to evacuation and emergency response
Smoke production reduces visibility, alters the thermal conditions within the space and makes it more difficult to locate the seat of the fire. Smoke curtains make it possible to contain, channel or confine the gases generated during a fire, in accordance with the smoke control strategy established for the building.
How to prevent electrical fires
To improve the safety of any building, it is essential to design the electrical installation correctly and invest time and resources in continuous maintenance. This helps keep installations in optimal condition and significantly reduces potential hazards.
Correct design of the electrical installation
The electrical design must take into account installed power, load diversity, load type, environmental conditions, protective device selectivity, ventilation, cable routes, enclosures, electrical panel locations and accessibility for maintenance.
Periodic maintenance and inspection of electrical panels
Inspections should include visual checks, technical cleaning, retightening of connections, testing of protective devices, insulation verification, temperature monitoring and documentary review of completed interventions.
Infrared thermography and hot-spot monitoring
Thermographic inspection makes it possible to detect thermal anomalies without dismantling equipment and while the installation is under load. It is particularly suitable for main switchboards, distribution boards, substations, motors, busbars and high-consumption equipment.
Housekeeping and control of combustible materials
Combustible materials must not be stored next to electrical panels, chargers, batteries, power equipment or areas with insufficient ventilation. Technical cleaning reduces the risk associated with accumulations of dust and combustible residues.
Staff training and emergency procedures
Personnel must be familiar with the warning signs of electrical faults, the limitations of intervention, the location of power isolation points, the available extinguishing equipment and evacuation procedures.
Protection systems for electrical fires
Protection against electrical fires must be based on a combination of systems capable of detecting, controlling and limiting the development of the fire. The selection of each solution will depend on the type of building, its intended use, the presence of electrical equipment and the evacuation conditions.
Temperature monitoring systems
Temperature monitoring and control systems are recommended to detect hot spots and prevent the development of sparks or flames. Thermal cameras or infrared thermography techniques may be used.
Early smoke, gas or temperature detection systems
Automatic detection systems are essential for alerting personnel to the hazard. High-sensitivity smoke or gas detectors are recommended.
Fire suppression systems
For electrical fires, systems that use water should generally be avoided. Gas or dry-powder suppression systems are recommended because they are non-conductive and can cause less damage.
Fire compartmentation and smoke barriers
Fire curtains and smoke barriers are essential for containing the fire within the area of origin and preventing its spread. This protects the rest of the building, reduces damage to stored goods and facilitates the evacuation of personnel.
What to do in the event of an electrical fire
The response to an electrical fire must prioritise personal safety and prevent uncontrolled intervention on energised equipment.
Isolate the electrical supply when it is safe to do so
Disconnecting the power supply reduces the risk of electric shock and facilitates emergency intervention. It must be carried out from a safe location, using the designated device and by trained personnel.
Do not use water on energised equipment
Water can conduct electricity and create a direct risk to people. It must not be used on live equipment until the power supply has been confirmed as isolated and safe conditions have been established.
Use extinguishing agents suitable for live electrical equipment
The extinguishing agent must be compatible with energised electrical equipment and the characteristics of the space. Its selection must be based on the emergency plan and the risk assessment.
Evacuate and contact the emergency services
If the fire cannot be controlled safely during its initial stage, the emergency plan must be activated, the affected area evacuated and the external emergency services notified.
Common mistakes when responding to an electrical fire
An incorrect response can increase the risk to people, contribute to the spread of the fire or damage critical equipment.
Attempting to extinguish it with water
Using water on energised equipment can cause electrocution, electrical arcing or the spread of damage to other components.
Handling electrical panels without appropriate training
Work on electrical panels, protective devices, conductors or busbars must be restricted to authorised and trained personnel.
Failing to isolate the electrical supply
Keeping the installation energised increases the risk of reignition, electric shock and continued electrical arcing.
Regulations and technical inspection of installations with electrical risks
Fire safety regulations establish criteria for reducing the risk of fire spread, facilitating evacuation and enabling intervention by the emergency services.
Fire safety in commercial buildings
In non-industrial buildings, Spain’s CTE DB-SI establishes the rules and procedures required to meet the basic fire safety requirements. These include conditions relating to internal fire spread, external fire spread, evacuation, fire protection systems, fire brigade intervention and the fire resistance of the structure.
Fire protection in industrial establishments
In industrial establishments, electrical risk analysis must be integrated into the building’s overall fire safety strategy. This involves reviewing the configuration of fire compartments, evacuation routes, fire protection installations, detection systems, the planned extinguishing systems and the measures used to control the spread of fire and smoke.
Royal Decree 164/2025 establishes that the Fire Safety Regulations for Industrial Establishments must make it possible to “facilitate rapid detection, limit fire spread and enable extinguishment”. This wording reinforces the need to address electrical fires through an integrated solution combining detection, compartmentation, smoke control and technical maintenance.
Why the protection plan should be reviewed if the building predates 2025
Existing buildings may have undergone electrical extensions, changes of use, the addition of batteries, chargers or connected equipment, the introduction of new process loads, or modifications to evacuation routes. These changes justify a technical review of the fire protection plan and of the compatibility between the electrical installation, fire compartmentation and smoke control systems.
How to improve electrical fire safety in your facility
Safety improvements should begin with a technical assessment of the building and its installations.
Preliminary risk assessment
The assessment must identify potential electrical ignition points, nearby combustible loads, fire and smoke spread routes, fire compartments, evacuation routes, critical equipment and emergency intervention conditions.
Selection of detection, extinguishing and compartmentation systems
Systems must be selected according to the specific risk scenario. This stage involves fire detection, extinguishing, fire engineering, compartmentation, smoke control and maintenance requirements.
Maintenance and continuous inspection plan
Maintenance must include functional testing, electrical inspections, reviews of fire protection systems, document control, incident recording and updates to the emergency plan whenever changes are made to the building’s use or configuration.