Which device is used to prevent electrical overloads and short circuits?

The device that is primarily used to prevent electrical overloads and short circuits is a circuit breaker. Circuit breakers are designed to automatically shut off the electric current when they detect an overload condition or a short circuit, thereby protecting the wiring and devices in the electrical system from damage. By interrupting the flow of electricity, they help to prevent overheating, potential fires, and equipment failure.

Unlike circuit breakers, contactors are designed for switching electrical circuits on and off but do not provide protection against overloads and short circuits. Relays serve similar functions in controlling circuits but are also not primarily designed for overload protection. Transformers, on the other hand, are used to change the voltage level in an electrical system and do not provide any protection against overloads or short circuits. Thus, the role of a circuit breaker makes it the correct and essential device for preventing damage in electrical systems.