What characteristics of the circuit being protected should be selected and coordinated to clear a fault without causing damage?

The selection and coordination of protective devices in a circuit are critical to ensuring that faults are cleared effectively without causing damage to the electrical system. The correct answer emphasizes the importance of considering both the total impedance of the circuit and the equipment's short-circuit current ratings.

Total impedance determines how much current will flow during a fault condition. This includes contributions from the wire size, length, and material, as well as any connected devices. By evaluating the total impedance, an electrician can better predict the fault currents that will occur, which assists in choosing protective devices that can react appropriately during a fault.

Furthermore, the short-circuit current ratings of the equipment indicate the maximum fault current the equipment can safely handle. Ensuring that the protective devices are coordinated with these ratings is key to preventing equipment damage during fault events. If a fault occurs and the protective devices do not clear the fault quickly enough or if they are not rated for the fault current level, the equipment may suffer from thermal and mechanical stress, leading to potential failure.

Thus, a comprehensive approach that involves both the total impedance of the circuit and the short-circuit current ratings allows for effective fault protection, minimizing the risk of damage to the electrical system and maintaining safety standards.