Final answer:
Grounding in AC systems is critical for electrical safety and involves creating low-resistance connections to the earth, ensuring the neutrality and safety of wires and appliance cases. Figures demonstrate a three-wire system with grounding and protective components like circuit breakers or fuses. This grounding prevents electrical hazards and maintains functionality within the system.
Step-by-step explanation:
The subject at hand is the grounding of service-supplied alternating-current (AC) systems, specifically the methodologies and safety considerations associated with system grounding connections. Grounding AC systems is a critical component for electrical safety to ensure that in the event of a fault, there is a low-resistance path directly to the earth. This set-up is essential to maintain a neutral wire at zero volts relative to the earth, ensuring safety and functionality of electrical systems.
In an AC system, there are typically three connections to earth/ground. One at the power source, which could be a generating plant, another at the user's location, and a third connection grounding the case of the appliance via a green earth/ground wire. These connections guarantee that the neutral wire is safe to touch, should its insulation be damaged, and provide an alternative path for the current to return to the source, completing the electric circuit.
Figures referenced depict a three-wire system with a three-prong plug showing how the appliance is connected and grounded for safety. The grounding also includes protection components like circuit breakers or fuses to protect against thermal overload, typically placed in series with the live/hot wire, which is responsible for supplying voltage and current to power an appliance.