The program's first demand-factor-driven design — where a single-dwelling load calculation gets replaced, not just scaled up, by a statistical method built for a population of similar units.
The project brief: a 4-story, 48-unit multifamily building, individually metered dwelling units, on a 480Y/277V utility service. This module walks the full distribution-approach decision (a single 480Y/277V service with owner-owned step-down transformers), the metering philosophy (individual dwelling-unit metering with a separate house meter), and a complete worked NEC 220.84 optional-method demand calculation across all 48 units.
It covers house/common loads (elevator, corridor lighting, common laundry, and the fire pump question), the transformer and 800A main switchboard sizing that follows from the demand calculation, and closes on exactly how this project's design method fundamentally differs from the single-family home's. The full worked numbers, bill of materials, and design reasoning are part of the unlocked module below.