Final answer:
The answer to the question is that a metal box or terminal fitting should be used when changing from conduit to Type AC cable. This requirement ensures safe and secure connections for conductors. Other wiring types do not require the same fittings.
Explanation:
Understanding Terminal Fittings and Conductor Changes
When transitioning from a conduit system to another type of wiring method, it is crucial to adhere to electrical code standards to ensure safety and proper function. A metal box or terminal fitting is necessary to provide secure connection points for each conductor. The question specifically addresses what type of wiring requires a metal box with separately bushed holes when changing from conduit.
The correct answer to this question is Type AC cable (option b). Type AC (armored cable) is typically used in settings where protection from physical damage is critical, and it requires secure terminal fittings for each conductor to maintain its integrity and safety measures.
In contrast, Type MC cable (option a) and nonmetallic sheathed cable (option c) have different protective features and wiring practices that do not mandate the same fitting requirements as Type AC. Knob and tube wiring (option d) is an older system that is largely outdated and does not fit the modern standards for conductors switching from conduit.
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