Electric safety specialists warn that extension cords should not be used as permanent substitutes for adequate electrical installation. The Electrical Safety Foundation International (ESFI) recommends that these cables be used only temporarily, without overloading, and never to power multiple high-consumption appliances simultaneously, as they can overheat and cause fires.
Large appliances such as refrigerators, washing machines, dryers, freezers and electric stoves should be plugged directly into a wall outlet. The U.S. Fire Administration warns that the risk is related to the high and prolonged consumption of these devices, which may have power spikes that the extension cord cable is not designed to handle. In the kitchen, toasters, microwaves, electric kettles, air fryers and coffee machines should also be plugged separately into the wall.
Portable heaters are considered among the most dangerous cases. ESFI advises plugging these devices directly into a wall outlet, without using extension cords or power strips, keeping them away from flammable materials such as curtains, clothing, carpets and papers. The danger increases when they remain plugged in for long periods or without supervision.
The National Fire Protection Association (NFPA) warns that extension cords should never pass under carpets, through doors, walls, ceilings or floors, as accumulated heat has more difficulty dissipating. Linking several extension cords together in sequence should also be avoided. When there is a constant need to use extension cords, a qualified electrician should be consulted to install more outlets.
