Final answer:
Runs of wiring in underground conduit are considered as secure locations, providing protection against physical damage and environmental factors. Plastic insulation on wires prevent both shock and thermal hazards by acting as a barrier against electrical contact and overheating.
Step-by-step explanation:
Runs of wiring in underground conduit are considered as secure locations. When properly installed, the conduit protects wires from physical damage and exposure to moisture and chemical degradation. It is important, however, to ensure that the correct type of conduit and wiring is used for the intended purpose to maintain the security and safety of the electrical system. For example, certain types of conduit are better suited for wet locations or hazardous environments.
Regarding plastic insulation on live or hot wires, it helps prevent both shock and thermal hazards. The insulation acts as a barrier to protect against electrical shock when a person might come into contact with a wire and also minimizes the risk of the wire overheating and causing a fire.