NEC Code Studio & Tools

New in v3: search all 165 diagrams instantly, jump back to recently viewed illustrations, share any diagram, and calculate residential service loads.

This app is a visual reference library for electricians, electrical engineers, inspectors, and students — covering the National Electrical Code from the utility service entrance all the way to branch circuits and special systems. Browse 165 hand-picked illustrations organized into 11 categories: Distribution Systems, Service Entrance, Panel Layouts & Schedules, Wiring Diagrams & Floor Plans, Grounding & Bonding, Overcurrent & Motor Circuits, Load Calculations, Low Voltage & Special Systems, Safety & Code Compliance, Fire Alarm Systems, and Building Automation. Search Illustrations Find any diagram instantly across all 11 categories. Search by title, topic, or NEC article — results appear as you type. Recently Viewed Your viewing history appears at the top of Browse so you can pick up right where you left off. No hunting through categories to find a diagram you were just studying. Share Any Illustration Send any wiring diagram, riser, floor plan, or code reference directly from the gallery to colleagues, students, or inspectors. Residential Load Calculator (NEC Article 220) Calculate service load the standard NEC method — general lighting, small appliance and laundry circuits, large appliances, HVAC, and optional loads all in one place. Results update live as you type, with automatic demand factor application, service size recommendation (100A–400A), and conductor sizing for the hot, neutral, and grounding electrode conductor. NEC Reference Requirements Plain-English summaries of key NEC requirements organized by chapter — from working space clearances and conductor terminations to GFCI protection, grounding, and equipment installation rules. Search by article number or topic to find what you need in the field, fast. Illustration viewer features: Swipe left and right to flip through illustrations within any category. Pinch to zoom in for fine detail and pan while zoomed. Double-tap to zoom in, double-tap again to reset. Bookmark any illustration as a favorite for quick access. Works on iPhone and iPad. Full Dark Mode support. A practical field and study companion for anyone working with the NEC.