Excess electricity flows through a short circuit , which causes heat , sparks, etc. When the voltage drops, the electric pressure increases. That is, voltage is called the pressure of electricity. When the excess voltage rises , a short circuit occurs. In more detail , the short circuit English short circuit , also referred to simply as short or s / c , refers to an electrical circuit that allows an inadvertent current to flow unintentionally to a connecting wire , because in this case there is almost no resistance or too much electricity. Less resistance is to be overcome. Excessive electricity can flow through a short circuit, causing heat or sparks of electricity. The opposite of a short circuit is an open circuit , where there is no resistance between the two points of the circuit. In general, many people do not know the real cause of any kind of electrical fault is called short circuit.