The Real Causes of Electrical Fires
According to Taşkın Ünal, an electrical engineer who has served as a fire expert witness in Istanbul’s courts since 1977, the overwhelming majority of fires are electrical — and most of them start on the drawing board. Ünal explains why not requesting as much power as you will actually use, EV chargers installed without a design, unventilated switchboards and equipment buried in basements all invite fire, drawing on cases from the Haydarpaşa Station fire to a 12-hour court hearing.
The 30-Second Summary
- Electrical fires usually start in the design. When one design is submitted to the utility and another is built on site, the real load exceeds the requested power; cables end up undersized, conductors heat up and connections deteriorate.
- Request as much power as you will use. Ünal’s rule is simple: build the infrastructure for the real load and "nothing will happen". When a military guesthouse wanted air conditioning in every room, he had a new transformer installed first.
- Voltage swings cause fires too. Voltage that sags under daytime load rises at night; that sudden surge can damage appliances and connections.
- No EV charger without a design. A home or apartment-complex charging station needs an electrical design, utility approval, inspection and acceptance; unauthorised installations are a leading cause of fires during charging.
- No airless switchboards, no chemicals in the basement. Switchboards must be ventilated, flammable and toxic substances must not be stored below ground, and static electricity must be earthed.
- An expert witness is an observer, not a rescuer. Ünal’s principle: write what you see — and if necessary, break with the panel and file a dissenting report.
Why Do Electrical Fires Start?
At the root of most electrical fires is an installation that was not built for the load it actually carries. The gap between the power requested and the power used pushes cables and connections beyond their capacity: conductors overheat, contacts loosen and degrade, an arc forms and nearby combustible material ignites.
The mistake Taşkın Ünal sees most often is made when the electricity supply is applied for. A design is drawn, the required reductions are applied and one design is submitted to the utility — but a different one is used on site. The power declared to the utility does not match the power used in practice. The result: supply shortfalls, blow-outs and cable cross-sections too small for the load.
The second factor is the grid itself. Ünal stresses that voltage drops, and the sudden surges when voltage climbs back at night, can damage equipment and start fires — and that the utilities share part of the responsibility.
In Ünal’s caseload the overwhelming majority of fires — "99.9 percent", in his words — are electrical. That is not a statistical measurement but a field observation distilled from court files; the message, though, is clear: you don’t play games with electricity.
- 1977Year he began serving as an expert witness in Istanbul’s courts
- 12 hrsLength of the hearing held to examine his dissenting report
- 3 fieldsBuilding, ship-and-yacht and electric-vehicle fires
How Does an Electrical Fire Develop, Step by Step?
An electrical fire does not happen in a single moment; it matures through small, compounding oversights. The chain below is compiled from Ünal’s account — each link makes the next one possible:
01 · Design and Power Demand
The design submitted to the utility differs from the one built on site
02 · Cable Cross-Section
A conductor too small for the real load runs hot all the time
03 · Contacts and Connections
A loose or oxidised connection gains resistance and heat
04 · Voltage Fluctuation
Voltage that sags by day rises at night; the surge stresses equipment
05 · Arc and Ignition
The heat of the arc ignites nearby combustibles
The Outcome: A Preventable Fire
Every link in the chain can be spotted by an engineer before a fire starts: comparing the design with the installation, checking cable sizes against the load, thermal scanning of switchboards and voltage protection. In an expert report, the same links are read in reverse.
Causes of Electrical Fires and the Dangers of Electric Vehicles
Electrical engineer and forensic fire expert Taşkın Ünal discusses the design-stage causes of electrical fires, the risks of EV charging stations, the Haydarpaşa Station fire, a shopping-mall fire hearing in İzmit and his advice for industrialists, hotels and yacht owners. (Interview in Turkish.)
Electric Vehicle Fires: Why a Charging Station Needs a Design
Ünal is not against electric vehicles: "Oil is running out, but electricity won’t; the coming era is the electric era." He does have one warning, though: you don’t play games with electricity. When people said "electric cars won’t catch fire in Turkey", his answer was simple: where there is a great deal of energy, that energy will be released somewhere.
Unauthorised charger installation
Charging stations in homes and apartment complexes are sometimes connected by unauthorised people, without a design or approval. That continuous, heavy load added to an existing building installation is power demand nobody planned for.
High energy in the battery
A vehicle battery stores an enormous amount of energy in a small volume. In Ünal’s view battery technology is still maturing; damage, overheating or faulty charging can release that energy uncontrollably.
Battery life, maintenance and swelling
Battery life, servicing and signs of swelling must be monitored. A battery that has taken an impact, is swollen or heats abnormally should be checked by an authorised service before it is charged.
5 steps to a safe charging station
- 1
Electrical design
The charger’s power, supply circuit and protective devices are set out in a design prepared by an electrical engineer.
- 2
Utility approval
The design is submitted to the distribution company, which assesses the connection capacity against the new load.
- 3
Licensed installation
The installation is carried out to the design by a licensed electrical contractor.
- 4
Inspection and acceptance
The installation is inspected before it is energised and is not used until it has been accepted.
- 5
Proper protection and servicing
Use a dedicated circuit, cable sized for the load and residual-current protection that also detects DC fault currents; keep the unit on a regular service schedule.
If a fire breaks out, who is liable?
According to Ünal, if a problem arises in an installation whose design was approved, inspected and accepted, the liability of the utility that approved it comes into play.
If the installation was rejected or never submitted for approval, liability falls mainly on the electrician who did the work.
/// Fault is apportioned case by case by the expert and the court on the basis of the evidence; the distinction above is Ünal’s general assessment.
Switchboard Ventilation and the Danger of Basements
When Ünal walks through a factory, a hotel or a shopping mall, he always looks at the same things first: where are the switchboards, do they get air, is there circulation? Where are the chemicals and how are they kept? "If you can’t control electricity it is very dangerous; if you can’t control chemicals it is very dangerous."
Basements and airless spaces
- Unventilated switchboards with no air circulation
- Solvents, thinners, paints and alcohol stored in the basement
- Transformers and medium-voltage equipment buried in deep basements
- Filling and transfer points with no earthing
Ventilated, accessible spaces
- Ventilated, clean switch rooms with clear access
- A separate, ventilated store for flammable materials
- Generators and power equipment on upper floors or outdoors where possible
- Earthed equipment that discharges static electricity
Static electricity: send it to earth
Ünal notes that flammable vapours and materials accumulating in enclosed spaces can become electrically charged on their own, and the human body carries static too. The fix is simple: discharge that charge to earth. Wherever flammable liquids are present, earthing equipment, containers and personnel is vital.
Two examples from the field
Three Files From Half a Century as an Expert Witness
Not all of Ünal’s files are electrical fires, but they share one lesson: lack of supervision and carelessness can burn down even the most solid building.
A Sunday, a Torch and Two Teenagers
One of the files that affected Ünal most is the Haydarpaşa Station fire of Sunday, 28 November 2010; as he recalls, the station clock stopped at 3:15 pm. It was not an electrical fire. Over the years the timber beams of the century-old building had decayed to the point where a hand would sink into them. Roof waterproofing was being done with a gas torch and large gas cylinders — by two 16-year-olds, with no foreman or supervisor present. When the match failed to light, gas built up; the moment the torch was lit, it flashed over.
One of the teenagers was burned but survived. Ünal’s question is about responsibility as much as technique: "Should a 16-year-old be put to work like this?" A historic landmark had been left in inexperienced hands, with no occupational safety, supervision or checks.
A Dissenting Report and a 12-Hour Hearing
In a major shopping-mall fire in İzmit, Ünal disagreed with the panel and filed a dissenting report. After reading it, the presiding judge of the criminal court of peace called him personally and asked him to attend the hearing. The courtroom held some 25 insurance investigators and lawyers. The hearing ran from morning to night — a full 12 hours.
The judge told the lawyers: "You cannot put questions to the expert directly; you will ask me, and if necessary I will have him answer." To Ünal, this was sound case management that protected the expert’s independence.
"Please, Brother, Save Us"
At a textile fire attended together with the court, 20 to 30 sacks had been piled together and set alight, and four or five of them had burned. The owner had sabotaged his own business. During the inspection he begged the expert: "Please, brother, save us."
Ünal’s reply: "I am not a rescuer, I am an observer. I write what I see." The report was written exactly as he found it and submitted to the court.
The Impartial Expert: Writing What You See
An expert witness may not know everything, but must be one thing: honest and impartial. What enlightens the court and the public is a report that records what the expert actually saw. The principles Ünal has repeated to younger experts for years:
- 01.
Write what you see
Much is asked of an expert; the parties’ expectations must never find their way into the report. The report reflects what the physical traces and documents show.
- 02.
Dissent when you must
If you disagree with the majority of the panel, file a reasoned dissenting report. In the İzmit mall case, that dissent was exactly what the court wanted to hear.
- 03.
Protect yourself first
Ünal’s principle at the scene and in life: "You cannot protect others without protecting yourself." Never enter a fire scene that has not been made safe.
- 04.
People come first
Property-damage fires can be prevented; fatal fires leave deep scars and long legal proceedings. The ultimate purpose of every report and every inspection is to protect human life.
“I am not a rescuer, I am an observer. I write what I see.”
Expert Advice for Factories, Hotels, Malls and Yacht Owners
The hotel fire at Kartalkaya in Bolu painfully exposed what a tourism country like Turkey still lacks. Ünal’s first point is about people, not technology: "First, we must never forget that we are human; we must be able to account for every step we take." Priorities by sector:
Industrial facilities
Risk:Flammable materials such as solvents, thinners, alcohol, paints and lubricating oils; heavy motor and switchboard loads.
- Store flammables in a separate, ventilated store — never the basement
- Earth all filling and transfer points
- Keep air circulating in switch rooms at all times
- Update the power demand whenever machinery is added
Hotels
Risk:Sleeping guests at night, many air-conditioning and kitchen loads, plant rooms pushed into basements.
- Don’t bury transformers, generators and switchboards deep underground
- Have the infrastructure assessed before every new AC or equipment load
- Test detection and sprinkler systems regularly
- Train the night shift on exactly what to do in a fire
Shopping malls
Risk:High fire load, tenant fit-outs and constantly changing electricity consumption.
- Make tenant fit-outs subject to design and approval
- Never allow switch rooms or service shafts to be used as storage
- Have detection and suppression systems audited by an independent expert
- Run regular drills for technical staff
Yacht and boat owners
Risk:Cramped, poorly ventilated engine rooms, humidity, vibration and electrical equipment added after delivery.
- Have shore power and charging systems installed by qualified people
- Check the ventilation of the battery compartment
- Inspect loose connections and corrosion at every service
- Ünal’s warning: "Pay close attention to yacht fires these days."
Electric vehicle owners
Risk:A heavy, continuous charging load added to an existing building installation; a high-energy battery.
- Have the charger installed with a design, approval and a licensed team
- Avoid routine charging from extension leads and household sockets
- Take a damaged or swollen battery to a service centre
- Keep the area around chargers in enclosed car parks clear
Electrical Fire Glossary
Short definitions of the key terms used in this guide:
- Power demand (connection capacity)
- The power requested from the utility when the supply is set up, and for which the installation is designed. If the actual load exceeds it, the installation is pushed beyond its capacity.
- Cable cross-section
- The conductor’s cross-sectional area in mm². It sets how much current the cable can carry; an undersized cable heats up and its insulation ages.
- Voltage drop
- The fall in voltage along a line under load. A sudden rise when the load falls away can also damage equipment and connections.
- Contact resistance
- Extra resistance at a loose, oxidised or deformed connection. As current flows the point heats up and can become an ignition source.
- Arc
- An electrical discharge jumping through air between two conductors. It can exceed the melting point of copper and ignite nearby combustibles.
- Residual-current device (RCD)
- A protective device that trips the circuit when it detects a difference between live and neutral current. For EV charging, a type that also detects DC fault currents is preferred.
- Earthing
- Safely conducting unwanted electrical charge from an installation and its equipment to the ground; also the basic defence against static electricity.
- Static electricity
- Charge that builds up through friction or flow. In an enclosed space it can produce a spark capable of igniting flammable vapours.
- Medium voltage
- The voltage level used in distribution networks, typically 34.5 kV in Turkey. Transformer rooms housing this equipment require special precautions.
- Thermal runaway
- In a lithium-ion battery, overheating in one cell spreading in a chain reaction to the others; it can cause fires that are very hard to extinguish.
- Dissenting report
- A report in which a member of an expert panel who disagrees with the majority sets out their own reasoned opinion separately.
- Sprinkler
- An automatic extinguishing head that opens at a set temperature and sprays water, together with the pipework that feeds it.
“Valuing people is what matters most. First you protect yourself, then the person in front of you — you cannot protect others without protecting yourself.”
Frequently Asked Questions
What is the most common cause of electrical fires?+
Why does an undersized cable cause fires?+
Can voltage fluctuations start a fire?+
What do I need to install an EV charging station at home or in an apartment complex?+
Do electric cars catch fire?+
Why must an electrical switchboard be ventilated?+
Can flammable chemicals be stored in a basement?+
How did the Haydarpaşa Station fire start?+
What is a dissenting report in expert witnessing?+
Check Today: 8 Points
The first things Ünal checks when he enters a facility; most can be settled quickly with an engineer’s site survey.
Taşkın Ünal
Electrical engineer. Since 1977 he has served as a forensic expert witness in Istanbul’s courts, focusing on electrical fires, ship and yacht fires and, in recent years, electric-vehicle fires. He worked as an electrical engineer at Fatih Municipality, as a director at the Istanbul Provincial Sports Directorate and as the manager responsible for hospitals’ electrical maintenance. He is an adviser to Yangın Kriminal and Tepeli Yangın Danışmanlık A.Ş.