What defines a short circuit?

A short circuit is characterized as an unintended low-resistance path that allows current to flow along a route not typically designed for it. This can occur when insulation fails or when conductors come into contact with one another inappropriately, creating a situation where the electrical current does not pass through the intended load or device. Since this path has significantly lower resistance than the normal pathway, it can result in a sudden surge of current that can cause damage, overheating, fires, or equipment failure due to the excess flow of electrical energy.

Understanding this definition is vital for electrical safety and engineering because recognizing the indicators of a short circuit can help prevent potential hazards. In contrast, the other options do not accurately describe a short circuit. A controlled low-resistance circuit is often part of design considerations for specific applications, while reducing resistance and increasing flow is an effect rather than a definition. The normal path for current in a grounded system also deviates from the concept of a short circuit, as it involves intended paths for current flow, typically with designed resistance and protection mechanisms in place.