What are the three primary categories of electrical equipment in a building's electrical system?

• A. Main, subpanel, outlets
• B. Conductors, devices, enclosures
• C. Service equipment, distribution equipment, and branch circuits
• D. Generators, transformers, meters

Answer: (C)

In a building’s electrical system, the equipment is grouped by function into three main categories: service equipment, distribution equipment, and branch circuits. Service equipment is where power enters the building and is controlled, such as the meter and main disconnect or service panel. Distribution equipment takes that power and routes it onward, including panel boards, switchgear, and feeders that split power to different areas. Branch circuits are the individual circuits that run from the distribution equipment to outlets, lighting, and fixed appliances, each protected by overcurrent devices.

This framing matches how the system is organized for design, protection, and coordination, making it the best answer. The other options describe specific components or smaller subgroups rather than the overarching functional categories used to categorize all electrical equipment in a building.