Journeyman Electrician License
NEC Calculators & Code Drills
USD 6.99 · Designed for iPad. Not verified for macOS.
Also Included In
New in v2: 7 live NEC calculators plus a spaced-repetition drill engine that remembers what you've nailed and what still needs work. 5 minutes a day, code-ready.
Built for working electricians: every tool you need on a real job site, plus a low-pressure drill engine that keeps the NEC fresh in your head.
WHY IT'S DIFFERENT
Most electrician apps are a wall of quiz questions. Electrician Prep is built around the math you actually do on the job — sizing a feeder, fitting a conduit, picking a breaker. Every calculation is live, every result cites the NEC article it's based on, and the drill engine adapts to you so 5 minutes a day is enough.
7 LIVE CALCULATORS
Voltage Drop — Single- or three-phase. Picks K, phase multiplier, and circular mils automatically. Flags ≤ 3 % / ≤ 5 % targets per NEC 210.19 IN and 215.2 IN.
Conduit Fill — Build a mixed-AWG THHN/THWN-2 bundle. Live total area plus the smallest EMT trade size that meets 40 % fill (Chapter 9, Table 1).
Box Fill — Count conductors by AWG, device yokes, cable-clamp groups, and the EGC bundle. Outputs cubic inches and matches against the standard box catalog (NEC 314.16).
Ampacity — Apply 310.15(B)(1) temperature correction and 310.15(C)(1) bundling adjustment in the right order. See the math broken out step by step.
Dwelling Load — Optional method (220.82). First 10 kVA at 100 %, remainder at 40 %, plus HVAC. Live service amperage and recommended next-standard service size.
Motor Amps — Table FLC lookup for Tables 430.247–430.250. Branch-conductor sizing at 125 %, OCPD up to 250 % (430.52), overload at 115 / 125 % per 430.32.
OCPD Sizing — Continuous-load 125 %, conductor ampacity ceiling, and the 240.4(D) small-conductor lockout enforced together. Catches the most common breaker-sizing mistake.
SPACED-REPETITION DRILLS
Cards are graded on confidence (Again / Hard / Good / Easy). Misses come back in minutes; solid answers come back in days — right when memory starts to fade. The Today's mix smart deck pulls cards due across every topic so a 5-minute session covers your weakest material first. Mastery shows as a per-topic percentage you can watch climb.
FIELD GUIDE
Search-first NEC reference. Type "GFCI" or "250.66" or "ampacity" and the matching atomic articles surface immediately. Every entry is short enough to read on a ladder.
TODAY TAB
Daily NEC tip rotated by date, the day's recommended drill mix, and a featured calculator. Open it once a day to keep your streak alive.
PROGRESS DASHBOARD
Per-topic mastery bars, current and longest drill streak, total card responses, and a breakdown of which calculators you use most. Reset anytime.
DESIGNED FOR REAL CONDITIONS
Dark, high-contrast theme readable in bright sunlight and low-light job sites
Optimized for iPhone and iPad, portrait and landscape
Works fully offline — no account, no sign-in, no internet required
All NEC tables and formulas built in
NOTES
NEC references reflect the 2023 code cycle. Always verify against the edition your jurisdiction has adopted and any state amendments. This app is a working aid, not a substitute for the official Code book or a licensed engineer's stamp.
Ratings & Reviews
- This app has not received enough ratings or reviews to display an overview.
Version 2.0 is a ground-up rebuild. This app is no longer a quiz-first study tool — it's now a daily field kit for working electricians, with seven live NEC calculators at the center of the experience and a spaced-repetition drill engine that adapts to you.
NEW IN THIS RELEASE
Five tabs: Today, Tools, Drills, Field Guide, Progress
7 reactive calculators that compute live as you type: Voltage Drop (1Φ / 3Φ), Conduit Fill, Box Fill, Ampacity (with temperature and bundling correction), Dwelling Load (optional 220.82 method), Motor Amps, OCPD Sizing
Every calculator shows the math step-by-step and cites the NEC article behind the result
Spaced-repetition drill engine — grade each card Again / Hard / Good / Easy and let this app schedule the next review for you
Today's mix smart deck pulls cards due across every topic, so 5 minutes a day covers your weakest material first
Per-topic mastery dashboard with visual progress bars
Daily NEC tip rotated by date — open the app once a day to keep your streak alive
Searchable field guide — type "GFCI" or "250.66" or "ampacity" and find the article in seconds
Refreshed dark interface tuned for bright job sites and low-light service work
Optimized for iPhone and iPad in portrait and landscape
WHY THE REWRITE
After listening to feedback, this app moved from "another exam quiz" to "a field utility you'd actually open mid-job." The drills are still there for licensing prep, but they're built into a daily habit instead of a single cram session. Open the Today tab tomorrow morning to see how it works.
NEC references reflect the 2023 cycle. Always verify against the edition adopted in your jurisdiction.
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
- Provider
- Yuhsiu Lai
- Size
- 4.9 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

