Electrical cables, also called conductors, come in many sizes and current ratings to power everything from a simple small appliance to heavy industrial equipment. The protection and control of electrical systems are essential to avoid overloads and short circuits. So what is the difference between the two?
overloads – Electrical conductors are sized for specific equipment based on the amount of current the equipment will draw. To ensure that conductors do not exceed their current rating (measured in amps), a protection device, usually a circuit breaker, is installed within the circuit with a current rating that matches that of the conductors. In an overload situation, the current flowing to the load exceeds the rated current of the conductor and thus of the circuit breaker. If prolonged, the circuit breaker protecting the circuit will heat up and “trip” opening the circuit to prevent damage to wiring or equipment. For example, too many appliances plugged into the same outlet and running at the same time could overload the circuit by exceeding its current rating. Without a circuit breaker, the conductors in the circuit could potentially heat up to the point where the insulating coating on the conductors melts creating a fire hazard.
short circuits – When a circuit path is interrupted, usually by accident, current does not flow to the load and a short circuit condition occurs. For example, if a table lamp is plugged into an outlet and its cord is suddenly cut by a wire cutter, there is little or no resistance in the circuit. This causes the current to reach a very high value and the breaker trips instantly.