Overheating (electricity)

Overheating is a phenomenon of rising of temperature in an electric circuit (or portion of a circuit). Overheating causes potential damage to the circuit components, and can cause fire, explosion, or injury. Damage caused by overheating are commonly irreversible; i.e. the only way to repair is to replace some components.

On overheating, the temperature of the part rises above the operating temperature. Overheating can take place

Overheating may be caused from any accidental fault of the circuit (such as short-circuit or spark-gap), or may be caused from a wrong design or manufacture (such as lack of proper a heat dissipation system).

Due to accumulation of heat, the system reaches to an equilibrium of heat accumulation vs. dissipation, at a much higher temperature than expected.

Circuit-breakers placed at different portions of circuit (in series to the path of current it will affect). If more current than expected goes through the circuit-breaker, the circuit breaker "opens" the circuit and stops all current. A fuse is a kind of widely used circuit breaker, that involves direct effect of Joule-overheating. A fuse is always placed in series with the path of current it will affect. Depending upon work, inside a fuse, there is a narrow (often a hairline) wire of definite-material, in the fuse. When more-than expected current flows through the fuse; the fuse-wire overheats (melts) and "opens" the circuit. In some gadgets, more than one

Many ventilator holes or slits kept on the box of equipments. Heat sinks (heat-radiating metallic objects) attached with some-portions of the circuit that produce more heat/ more vulnerable to heat. often, fans are required. Some high-voltage instruments kept immersed in oil. In some cases, to remove unwanted heat, some cooling-system like air-condition or refrigerating-heat-pumps may be required.

Sometimes special circuits built for purpose of sensing the temperature or voltage status, and thereafter controlling these variables. In these circuits, Thermistors (Temperature dependent resistors), VDR (voltage-dependent resistors), thermostat (that switches off the circuit at higher-temperature), Sensors (such as infrared-thermometers), etc. used to modify the current upon different conditions like circuit-temperature and input voltage.

For a certain definite purpose in a definite electrical equipment or a portion of it, definite type and size of materials (for boards,wires, insulators) with proper rating for voltage, current and temperature,are used. The circuit-resistance never kept too-low. Sometimes some parts placed inside the board and box, maintaining a proper distance from each-other, to avoid heat-damage and short-circuit-damage. To prevent short-circuit, on the wire-joints, appropriate type of electrical connectors and mechanical fasteners used.

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