Commercial Electrical Design
NEC Reference & Calculators
$4.99 · Designed for iPad. Not verified for macOS.
The complete field reference for commercial electrical design —
illustrated drawings, NEC code articles, 10 load calculators,
and step-by-step design calculation guides.
Commercial Electrical Design is a visual reference and calculation tool for electrical engineers, designers, electricians, and students working on commercial building projects.
Built around a real-world commercial strip mall, the app puts professional electrical illustrations, NEC code look-up, interactive calculators, and step-by-step design calculation guides in one place — offline, on iPhone and iPad.
BROWSE — ILLUSTRATED DRAWINGS
23 professional illustrations in 8 design categories:
• Floor Plans & Key Plans — dimensioned tenant layouts and color-coded key plans
• Electrical Plans — device plans with lighting, receptacles, switches, and panels
• Wiring Layouts — branch circuit home runs and wiring path diagrams
• Electrical Symbols & Legend — full device symbol reference
• Panelboard Schedules — 200A, 208Y/120V, 3-phase schedules for Shops A, B, C, and the Building 2 main distribution panel
• Panelboard Load Worksheets — conductor sizing tables with OCPD ratings and wire sizes per circuit
• Feeder Load Calculation Worksheets — NEC Article 220 calculations for each tenant and the building main
• Conductor & Conduit Sizing Steps — step-by-step sizing sheets for phase, neutral, and grounding conductors
Pinch to zoom up to 6× on any illustration. Swipe between images in the same category. Save any illustration to Favorites for fast retrieval.
NEC REFERENCE
Searchable, expandable code cards for the articles most relevant to commercial design:
• Article 210 — Branch Circuits
• Article 215 — Feeders
• Article 220 — Branch Circuit, Feeder & Service Calculations
• Article 230 — Services
• Article 240 — Overcurrent Protection
• Article 250 — Grounding and Bonding
• Article 310 — Conductors for General Wiring
• Article 408 — Switchboards, Switchgear & Panelboards
CALCULATORS
Ten interactive calculators covering the full commercial design workflow:
1. Branch Circuit Load — NEC 220.12 unit loads by occupancy type
2. Feeder Load — lighting, receptacles, motors, and HVAC
3. Voltage Drop — AWG 14–0, pass/fail at 5% limit
4. Wire Sizing — minimum AWG to meet a voltage drop target
5. Conduit Fill — NEC Chapter 9, 40% fill, EMT sizes to 3"
6. Panel Load Balance — 3-phase A/B/C VA imbalance check
7. Demand Factor — NEC Table 220.42 tiered demand factors
8. Short Circuit Current — transformer kVA and impedance input
9. Power Factor Correction — kVAR sizing and current reduction
10. Service Size — combined loads to NEC 240.6(A) standard OCPD
DESIGN CALCULATIONS
Seven step-by-step calculation modules drawn from the illustrated worksheets, each with NEC references, formulas, and worked examples:
1. Branch Circuit Load Worksheet — classify loads, apply 125% continuous factor, select OCPD and conductor size
2. Feeder Load Calculation — NEC Article 220 procedure with real Shop A/B/C examples
3. Phase Conductor Sizing — Table 310.15(B)(16) at 75°C with temperature correction
4. Neutral Conductor Sizing — NEC 220.61 natural load method and phase imbalance analysis
5. Equipment Grounding Conductor — NEC Table 250.122 lookup and proportional increase rules
6. Conduit Fill & Trade Size — Chapter 9 wire areas, 40% rule, EMT and PVC trade size selection
7. Panelboard Load & Phase Balancing — Building 2 Panel L1 full worked example with phase A/B/C distribution, continuous load adjustment, demand current, and neutral unbalance
FOR iPHONE AND iPAD
Fully responsive layout adapts to any screen size and orientation. All content is available offline — no subscription or account required.
Ideal for electrical engineering students, practicing engineers, electrical designers, contractors, and inspection professionals working with NEC-based commercial electrical systems.
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The developer, Yuhsiu Lai, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Yuhsiu Lai
- Size
- 44 MB
- Category
- Education
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 iTech Tools
