What is a common safety feature added to electrical installations to protect against ground faults?

The correct choice is GFCI, which stands for Ground Fault Circuit Interrupter. This device is specifically designed to protect people from electric shock by detecting ground faults—situations where electrical current is unintentionally flowing to the ground. It works by constantly monitoring the amount of current flowing through the circuit. If it detects an imbalance between the outgoing and incoming current, this indicates that some of the current is escaping, which could potentially lead to a shock hazard. In such cases, the GFCI interrupts the circuit almost instantaneously, greatly reducing the risk of serious injury or death from electrical shocks.

The inclusion of a ground wire is beneficial for overall safety and proper functioning of electrical systems, but it does not actively monitor or interrupt current flow in the event of a ground fault. A breaker switch provides overload protection by cutting off the circuit when the current exceeds a certain level, but it does not specifically address ground faults like the GFCI does. A transformer, while crucial for voltage conversion and regulation, does not serve a protective function in the context of ground faults.