Final answer:
The question focuses on grounding in electrical systems, specifically ungrounded systems' connectivity before the service disconnect. Grounding functions to avoid electric shock or fire hazards by creating a path to earth. Techniques like the three-wire system and insulation help prevent shock and thermal hazards in coordination with circuit breakers and fuses.
Step-by-step explanation:
Understanding Grounding in Electrical Systems
The question at hand deals with grounding systems and their connectivity on the supply side before the service disconnect. Specifically, it addresses a scenario in which an ungrounded system is in use. Grounding is critical for electrical safety, preventing both thermal and shock hazards by creating a low-resistance path to the earth. This helps avoid hazardous potential differences that could cause electric shock or fire hazards.
Electrical safety is a paramount concern in designing and maintaining environments where electrical systems operate. Key devices such as circuit breakers and fuses are employed to interrupt potentially dangerous overcurrents. The three-wire system is another essential safety feature, where the case of the appliance is connected to the neutral wire, which is tied to the earth, setting it at zero voltage, and thus, providing an alternative path for current that may stray from the hot/live wire.
Plastic insulation on the live/hot wires is intended to prevent shock hazards by insulating the conductive wire from accidental contact. While it does prevent contact with live wires that could result in electric shock, it does not directly prevent thermal hazards, which are more related to the amount of current flowing through a wire and the resultant heat generation. However, in conjunction with circuit breakers and fuses, which are designed to protect against thermal hazards, it forms part of an integrated safety system.