Just after 3.48 a.m. on May 3, 2026, fire ripped through a four-storey building in Vivek Vihar, East Delhi, killing nine. The suspected origin was an AC blast or short circuit.
Ten newborns died in an overcrowded Jhansi NICU in November 2024, a unit meant for 18 babies packed with 55. Three newborns in Amravati this August, dead not from flame but from smoke inhalation, even though the fire itself was out within 30 minutes. One newborn in Chhindwara two days before that. Ten patients at Cuttack’s SCB Medical College this March, when a short circuit in a trauma-ICU air-conditioner ignited an oxygen-rich ward at 3 a.m.
Fire accidents in India used to happen in industrial units, firecracker factories and mass gatherings. No more. The more devastating ones happen right in our neighbourhoods, in hospitals and high-rises. They are almost always triggered by electrical fires.
Delhi Fire Service attributes over 80% of the capital’s fires to electrical faults. Mumbai Fire Brigade, analysing 26,855 incidents over five years, attributes nearly three in four to the same cause. New Delhi alone saw a 37% rise in residential fires this year over last, with roughly 70% traced to short-circuiting, faulty wiring, overheating, and overloaded circuits. The National Crime Records Bureau recorded 7,566 fire accidents and 7,435 deaths in 2022, with short circuit consistently among the largest single causes.
Indian electricity demand hit 256.11 GW on April 25 this year, against air temperatures of 47 degrees, roughly double the early-2010s peak. A/Cs draw about 50 GW at peak. And projections place the A/C load at 180 GW in another 10 years. Indians bought more than 15 million air-conditioners in 2025 alone, and the International Energy Agency expects the installed base to climb from 93 million units in 2024 to 240 million by 2030.
Air-conditioners draw heavy current that electrical systems in older buildings are unable to withstand, resulting in the wiring burning up. What’s called an A/C blast is the overworked compressor in the refrigeration exploding due to sheer heat caused by overworking. Investigation into these fires has been hampered by shortage of certified fire forensic investigators. Too often, the causes are dismissed as blasts or short circuits. Root cause analysis and systemic remedies are rarely formulated.
How electrical fires happen?
An electrical circuit has three parts. The load is whatever draws current. It could be just a light or an air-conditioner. The wiring carries that current, insulated to keep two conductors from touching. The protection device, typically a miniature circuit breaker, is meant to cut the current flow the instant something goes wrong. The circuit breaker switches off the current within about a tenth of a second for a short circuit, or within a longer window, from a minute to an hour, for a sustained overload. A fire needs two failures at once: something in the load or wiring goes wrong, and the protection device fails to trip in time.
A peer-reviewed 2025 review in the journal Fire identifies six recurring failure modes behind that first failure: short circuits, overloads, loose or oxidised connections, series and parallel arc faults, ground faults, and equipment ageing. Of these, a loose connection is often the quietest killer. Research on wiring practice, cited in Indian engineering literature reviewing fire risk in electrical installations, shows that loose terminal connections, whether from bad workmanship, thermal expansion and contraction, or simple ageing, create a phenomenon called glowing contact: a slow-building hot spot that can smoulder in a wall or panel for months before anything is visible from outside.
There is a second, slower mechanism that gets far less attention and could explain a great deal about how India’s fires happen: harmonics. Every inverter-driven air-conditioner, along with every UPS, LED driver, ventilator and EV charger, draws current in short, jagged pulses rather than a smooth wave. This injects distortion into the electrical supply at multiples of the base 50 Hz frequency. In three-phase buildings, certain harmonic orders, called triplen harmonics, do not cancel out in the neutral conductor the way normal, balanced current does. Instead they add up. The neutral wire, which was never designed to be load-bearing and carries no circuit breaker of its own, quietly overheats. A loose joint nearby could make an overheated neutral become an ignition source ripping up ordinary insulation.
Fire investigators suspect that many chemicals and solvents are used in ICUs and the vapours they generate don’t get evacuated well-known enough because of poor maintenance of ventilation systems. They point out that ICUs have dedicated ventilation systems and need much care. While these vapours provide the fuel, a source of heat is required for ignition. And that is where harmonics-generated heating could come into play, says a fire forensic engineer who didn’t wish to be named. “Electrical fires are a gray area and require a lot of precautions. Sadly, in India, compliance with regulations is considered a financial burden,” he adds.
Medical equipment damaged after a fire broke out in the neonatal intensive care unit of a government hospital killing three newborns, in Amravati district of Maharashtra. | Photo Credit: EMMANUAL YOGINI
Among the first cases of a spectacular failure due to harmonics happened in September 2010, when a capacitor inside a harmonic filter aboard the cruise liner Queen Mary 2 failed while the ship approached Barcelona with 3,823 people aboard. The explosion blacked out the vessel.
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