Short circuit

This results in an electric current limited only by the Thévenin equivalent resistance of the rest of the network which can cause circuit damage, overheating, fire or explosion.

A common type of short circuit occurs when the positive and negative terminals of a battery or a capacitor are connected with a low-resistance conductor, like a wire.

With a low resistance in the connection, a high current will flow, causing the delivery of a large amount of energy in a short period of time.

In electrical devices, unintentional short circuits are usually caused when a wire's insulation breaks down, or when another conducting material is introduced, allowing charge to flow along a different path than the one intended.

To help reduce the negative effects of short circuits, power distribution transformers are deliberately designed to have a certain amount of leakage reactance.

The arc, a channel of hot ionized plasma, is highly conductive and can persist even after significant amounts of original material from the conductors has evaporated.

The temperature of the resulting electrical arc is very high (tens of thousands of degrees), causing the metal on the contact surfaces to melt, pool and migrate with the current, as well as to escape into the air as fine particulate matter.

An electric arc, if it forms during the short circuit, produces high amount of heat and can cause ignition of combustible substances as well.