Real-World Scenarios

Walk through a complete NEC 220.82 (optional method) residential service calculation for a typical 2,500 sq ft single-family home with central A/C, electric range, dryer, and water heater.

Size and install a 60A, 240V feeder from the main panel to a detached garage 85 feet away. The garage will have general lighting, receptacles, and a future EV charger circuit.

Install a 48A hardwired Level 2 EVSE (Tesla Wall Connector) in an attached garage on an existing 200A residential service. Verify panel capacity and size the circuit.

Calculate the total building service for a 12-unit apartment complex. Each unit is identical: 1,200 sq ft with electric range, dryer, A/C, and water heater. NEC provides generous demand factors for multi-dwelling buildings.

Design the electrical distribution for a 3,000 sq ft commercial office tenant space in an existing building. The landlord provides a 100A, 208Y/120V tap from the building transformer for the tenant panel.

Calculate the electrical demand for a full-service restaurant kitchen with commercial cooking equipment, applying NEC Table 220.56 demand factors for commercial kitchen loads.

Design the lighting circuits for a 120-space parking lot with LED pole-mounted luminaires. This involves calculating the number of fixtures, sizing circuits for long conduit runs, and addressing voltage drop.

Design a motor control center (MCC) serving five motors in an industrial facility. Size the feeder, branch circuits, overloads, and SCGF protection per NEC 430.

Design the electrical supply for a 50 HP electric fire pump in a commercial building. Fire pump circuits have unique NEC requirements that differ significantly from standard motor circuits.

Design the power distribution for a 200 kW IT load data center with 2N redundancy, including transformer, UPS, and PDU sizing. This is a Tier II facility with a single utility feed and UPS backup.

Design a 10 kW-DC rooftop solar PV system for a single-family home with a 200A main panel. Includes module layout, string sizing, inverter selection, and interconnection per NEC 690 and 705.

Install a 100 kW natural gas standby generator with an automatic transfer switch (ATS) for a small commercial building, covering emergency, legally required standby, and optional standby loads.

Design a whole-home battery backup system (e.g., Tesla Powerwall, Enphase IQ Battery) for a 200A residential service. The system will provide backup during grid outages and pair with an existing 10 kW solar PV system.