Vivek Vihar, in Delhi's Shahdara, where a fire claimed nine lives. (Express photo by Abhinav Saha)A fire broke out at a residential complex in East Delhi’s Shahdara on Sunday morning (May 3), resulting in the deaths of at least nine people. Initial reports suggest that an air-conditioner (AC) blast might have triggered the fire.Summer months often see reports of loss of life and property due to AC malfunctions. With higher average temperatures year-on-year and rising nationwide AC sales, the likelihood of such incidents increases. How exactly do the fires happen, and what can you do to prevent them? We explain.How do ACs catch fire?During the summer, continuously running electrical appliances can lead to overheating, also due to the high average atmospheric temperature. Another major reason is short-circuiting, or when the flow of electric current in a circuit goes in another direction. This is not always dangerous, but when a large amount of current is flowing, it can, in turn, generate a great amount of heat. This can melt wires and lead to a fire.Generally, MCBs (Miniature Circuit Breakers) are installed to trip the circuit as soon as an overload is detected. According to the Schneider Electric website, “MCBs are equipped with a bimetallic strip that is sensitive to heat. If there are high amounts of current flowing through the circuit, it warms up the bimetallic circuit in the MCB which bends and deflects from its original state. This deflection causes the MCB to “trigger” and release a mechanical latch. This latch disconnects the circuit and disrupts the electrical flow from reaching the connected device.” Later, a switch can be turned on to resume the normal flow of electricity.Often, it is a fault in the MCB which leads to this mechanism failing, resulting in fires.The Republic of ACs | India’s growing need for cool airThe Delhi government’s Department of Fire Services states that “About 60% fires are of electric origin on account of electric short circuit, overheating, overloading, use or non standard appliances.”How to know when your AC may pose a safety riskAccording to Haier, some common symptoms of a potential blast include unusual noises from the unit, frequent cycling on and off, inconsistent cooling of the room, and burning smells/smoke. Professional repair services should be called in to fix these issues.Story continues below this adWhat are some precautions for preventing AC fires?In the case of split ACs, both the inside and outside units are potential fire hazards. Usually, the inside unit comprises the evaporator (which removes the heat from the air), the blower and the filter nets. The outside unit includes the compressor that helps chill the air blowing indoors and the fan to dissipate the hot air being released outside.Here are some do’s and don’ts to ensure your AC is in good health:*LG’s manual for ACs says that both indoor/outdoor wiring connections must be secured tightly, and the cable should be routed properly so that there is no force pulling the cable from the connection terminals. Weak connections can cause heat generation or fire.*Users must ensure that the circuit breaker and fuse are in good condition.Story continues below this ad*If your locality witnesses frequent electricity fluctuations, consider installing a stabiliser, which can protect your appliance by supplying constant current to it.*Any modifications or installations in the setup should be done with the help of authorised repair centres. Regular maintenance is recommended. Haier also recommends regularly cleaning the dust that settles on air filters, since it can hinder air flow and put pressure on the system.*Ideally, the temperature must be set between 24 and 26 degree Celsisus. A very low setting can stress the system.*The indoor unit should not come in contact with water.Story continues below this ad*Do not place objects in direct proximity to the outside unit. Letting dry leaves and other debris accumulate around the unit can be dangerous. Leaves could also attract small animals that can enter the unit.*Do not run the appliance continuously, or frequently switch it on and off. The main power switch must be turned off if it is not used for a long time.