According to the NEC, what is required for the installation of metal raceways?

In the context of the National Electrical Code (NEC), the requirement for the installation of metal raceways centers around the necessity for proper grounding. Metal raceways, such as conduits and tubing, provide a pathway for electrical conductors but also serve as a means to ensure safety. Proper grounding of metal raceways is essential to protect against electrical faults and to ensure that any fault current is directed safely to the ground. Grounding helps to prevent electrical shock hazards and reduces the risk of fire by ensuring that fault currents are effectively managed.

This requirement aligns with the NEC’s focus on safety and performance, as grounded metal raceways facilitate the establishment of a low-resistance path for fault currents. By doing this, they contribute to the overall safety and effectiveness of the electrical system.

Other options do not accurately represent NEC requirements for metal raceways. While insulation or protective coatings might be necessary in specific conditions, they're not a blanket requirement for all installations of metal raceways as grounding is. Similarly, color coding might be relevant in some contexts, but it is not a general requirement of the NEC for metal raceways. Thus, the emphasis on proper grounding is a fundamental aspect highlighted by the NEC for ensuring safety in electrical installations.