What is meant by the term short circuit?

Answer 1

When a wire is cut in a circuit, a gap is made and the current can no longer circulate, known as an open circuit.

When 2 parts of a circuit touch, that shouldn't, for example - a wire comes loose and comes into contact with another part of the circuit, its shortening the route of the current in the circuit. So its a short circuit. When this happens 99.9% of the time the result will be a spike in amp's, so tripping any circuit protection, MCB's, fuses.

A good example of a common short circuit is faulty windings on a 3-phase electric motor. If the resin separating the windings becomes damaged it can cause 2 or even 3 of the motors phases to come into contact causing the motors overload protection to trip.

Answer 2

A circuit typically has a load on it, in a symplified model there is a power source, and a resistance in series with it. The power drawn from the source will be P = I^2 * R. If the resistance was "short circuited", meaning a wire was run in parallel to the resistor from the positive side of the power source to the ground, the system would be short circuited. Maximum current would flow. In your house, short circuiting an outlet would be to take a piece of wire and plug one end into a power outlet, and the other into the other side of that same outlet. This will cause breakers (hopefully) to open in the breaker box in your house.

Answer 3

Electricity travels in a path of least resistance. A short circuit can be classed as a circuit of very little or no measurable resistance. In a short circuit the supply voltage returns directly to the return conductor or a grounded medium as this circuit has a lower resistance that the load resistance. The load resistance in a circuit is what controls the amperage flowing in the circuit. A short circuit with a very low resistance and a very high current flow can do significant damage if not stopped immediately. This is why circuits have over current protection to interrupt this high current flow.