Short-circuit protection and overload protection – what is the difference

Short-circuit

The current rises very sharply and can reach a very high value. Protection must operate immediately.

Overload

The current is higher than normal but not necessarily huge. The damage is caused by overheating over time.

Why we need both

A protection circuit breaker may have a thermal element for overload and a magnetic element for short-circuit.

Example

A stalled motor can create an overload, while a phase-to-phase or phase-to-neutral contact can create a short-circuit.