This free interactive 3D walkthrough takes you through the electrical system of a single-family home — service entrance, meter, main panel, AFCI/GFCI breakers, branch circuits, lighting, smoke/CO alarms, and an EV charger. Click any component to see what it does and the NEC rule behind it. It's a visual learning tool for homeowners, electricians, designers, and students who want to understand how residential wiring fits together per NEC 2020.
The walkthrough covers the dwelling's electrical system from the utility to each device:
• Service entrance and meter — the service drop or lateral and the utility meter feeding the home. • Main panel (load center) — the main breaker and bus distributing power to the branch circuits. • AFCI and GFCI breakers — arc-fault and ground-fault protection at the panel. • Branch circuits — lighting, receptacle, and appliance circuits routed through the house. • Lighting and devices — fixtures, switches, and receptacles in each room. • Smoke and CO alarms — interconnected life-safety devices. • EV charger — a dedicated 240V circuit per NEC 625. • Low-voltage — doorbell, thermostat, and data wiring.
Utility power enters through the service entrance and meter and lands on the main panel. The main breaker protects the service, and the panel bus distributes the two 120V legs (240V across them) to individual branch-circuit breakers. Each breaker feeds a circuit sized to its load — 15A or 20A for general lighting and receptacles, and larger dedicated circuits for the range, dryer, HVAC, and EV charger. AFCI breakers protect most living-area circuits against arcing faults, GFCI protection guards wet and outdoor locations, and interconnected smoke/CO alarms provide life safety throughout the home.
1. Drag to orbit the house, scroll to zoom, and pan to move around the 3D model. 2. Click any piece of equipment or device to highlight it and read what it does plus the relevant NEC reference. 3. Follow each circuit from the service entrance → meter → main panel → breaker → branch circuit to the device it serves, noting where AFCI or GFCI protection applies.
Under NEC 2020, AFCI protection is required for most 120V, 15A and 20A branch circuits in living areas — bedrooms, living rooms, kitchens, hallways, and similar spaces. GFCI protection is required for receptacles in wet or damp locations: bathrooms, kitchen countertops, garages, outdoors, crawl spaces, unfinished basements, laundry areas, and near sinks. Dual-function AFCI/GFCI breakers are often used to satisfy both.
The service entrance is where utility power enters the building — the overhead service drop or underground lateral, the meter, and the service-entrance conductors running to the main panel. It includes the main service disconnect, the single switch that cuts all power to the home.
Panel (service) size comes from an NEC Article 220 load calculation: add the general lighting and receptacle load (based on square footage), small-appliance and laundry circuits, fixed appliances, and the larger of heating or cooling, then apply demand factors and divide by 240V. Most modern single-family homes use a 200A service, with smaller homes on 100A or 150A.
A branch circuit is the wiring between the breaker in the panel and the outlets or equipment it serves. The breaker rating defines the circuit — a 20A breaker on 12 AWG copper, for instance — and a circuit may serve several receptacles or a single dedicated load such as the range or EV charger.
A Level 2 home EV charger uses a dedicated 240V branch circuit installed per NEC Article 625, commonly 40A–60A and often GFCI-protected. The circuit is sized to the charger output (continuous load at 125%), and the panel must have confirmed spare capacity via a load calculation.