<P> A high current flowing through a battery can cause a rapid increase of temperature, potentially resulting in an explosion with the release of hydrogen gas and electrolyte (an acid or a base), which can burn tissue and cause blindness or even death . Overloaded wires will also overheat causing damage to the wire's insulation, or starting a fire . High current conditions may also occur with electric motor loads under stalled conditions, such as when the impeller of an electrically driven pump is jammed by debris; this is not a short, though it may have some similar effects . </P> <P> 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 . </P> <P> In mains circuits, short circuits may occur between two phases, between a phase and neutral or between a phase and earth (ground). Such short circuits are likely to result in a very high current and therefore quickly trigger an overcurrent protection device . However, it is possible for short circuits to arise between neutral and earth conductors, and between two conductors of the same phase . Such short circuits can be dangerous, particularly as they may not immediately result in a large current and are therefore less likely to be detected . Possible effects include unexpected energisation of a circuit presumed to be isolated . To help reduce the negative effects of short circuits, power distribution transformers are deliberately designed to have a certain amount of leakage reactance . The leakage reactance (usually about 5 to 10% of the full load impedance) helps limit both the magnitude and rate of rise of the fault current . </P> <P> A short circuit may lead to formation of an electric arc . 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 . Surface erosion is a typical sign of electric arc damage . Even short arcs can remove significant amounts of material from the electrodes . The temperature of the resulting electrical arc is very high (tens of thousands of degrees Fahrenheit), 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 . </P>

Which electrical condition is characteristic of a short circuit