When are circuit breakers typically used in electrical systems?

Circuit breakers are essential components in electrical systems primarily used to prevent overloads and electrical faults. Their main function is to automatically shut off the electrical supply when they detect abnormal conditions, such as excessive current flow (overload) or short circuits. This protective mechanism helps to avert potential hazards, including electrical fires, equipment damage, and personal injury. By interrupting the flow of electricity, circuit breakers ensure that the electrical system operates safely and effectively, preserving the integrity of both the wiring and connected devices.

The other options focus on aspects not related to the primary purpose of circuit breakers. Enhancing voltage signals is not a function of circuit breakers; instead, they focus on current control for safety. Circuit breakers are not designed to increase current levels; their role is to interrupt current flow when necessary. Finally, while they are indeed used when installing new systems, their use is not limited to new installations, as they are crucial in all types of electrical systems to provide ongoing protection.