Final answer:
The neutral wire in a grounded system is connected to earth, ensuring it is at zero volts and provides a safe path for current to return to the source. A three-wire system includes a live/hot wire, a neutral, and a ground, offering protection against electrical hazards through various safety features.
Step-by-step explanation:
The question pertains to the function of the neutral wire in a grounded electrical system. In such a system, the neutral wire is connected to earth/ground at both the voltage source (such as a generating plant) and the user's location. This connection ensures that the neutral wire is at zero volts relative to earth, making it safe to touch, and provides a low impedance return path for fault current.
The three-wire system also includes a live/hot wire, which supplies voltage and current to operate appliances. The grounding of the neutral wire and the appliance case, typically through a green earth/ground wire, helps to protect against electrical shock. Additional safety features, like circuit breakers or fuses and ground fault circuit interrupters (GFCIs), provide protection against thermal overload and electric shock, respectively.