What type of devices are generally used as overcurrent protection for appliances in branch circuits?

Overcurrent protection for appliances in branch circuits is primarily achieved through the use of fuses. Fuses are designed to interrupt the flow of electricity when the current exceeds a predetermined level, thus protecting both the wiring and the appliances from damage that can occur due to overheating or electrical faults.

In a branch circuit, safety is critical, and fuses serve as a crucial component to ensure that electrical systems do not carry more current than they can safely handle. They work by melting a metal wire within the fuse casing when excess current flows through it, effectively breaking the circuit and stopping the flow of electricity. This functionality is particularly vital for household appliances, where equipment could become hazardous if overcurrent is not adequately managed.

The other options do not serve as overcurrent protection. Transformers are used to change voltage levels in electrical systems, capacitors store electrical energy and can help with reactive power issues, while resistors limit current flow but do not provide an automatic cut-off in the event of an overload. Therefore, fuses are specifically designed for the purpose of overcurrent protection, making them the correct choice.