An electrical short circuit, also called a circuit interruption, often occurs when the wire coating is stripped or when a nail passes through the wire. This generates a spark, which can set fire to nearby combustible material or damage an appliance or other fixture connected to the wires.
The most common short circuits occur between a live wire and a neutral wire, but any two wires can short circuit. For example, if a neutral wire comes into contact with a ground wire, it is possible for that connection to create a short circuit.
If a homeowner is hammering a nail through a wall, and the nail comes into contact with two wires, it can establish a connection. The same thing happens when the coating is stripped from wires that can come into contact.
Short circuits can also occur in batteries. If the positive and negative terminals are connected by a wire, a surge of electrical current can generate sufficient heat to cause an explosion.
To prevent short circuits in homes, electricians install fault protection devices, such as circuit breakers and fuses, that shut down the electrical current when the system detects a surge. These devices are designed to permit only a certain level of electrical current, such as 20 amperes. If that level is exceeded, the circuit trips so the short circuit or overload does not cause a fire or other damage. Ground wires combined with circuit breakers also prevent other electrical problems, such as arcs and electrical shocks.