Sparky's Black Book
Offline NEC Electrical Toolkit
Free · Designed for iPad. Not verified for macOS.
Every number you calculate in the field is either code or it isn't. Sparky's Black Book gives you 58+ NEC-grounded calculators that run completely offline — in the basement, the MDF room, the rooftop, wherever the job takes you.
THE NEC, NOT AN APPROXIMATION
Sparky's Black Book uses the actual tables. 310.16 and 310.17 for ampacity. 430.247, 430.248, and 430.250 for motor branch circuits. Chapter 9 Tables 1, 4, 5, and 8 for conduit fill. 314.16 for box fill. 250.66 and 250.122 for grounding electrode and equipment grounding conductors. Real values from the code — not estimates from memory or a third-party website.
Every result comes back with a pass/fail compliance flag. If your selection is out of spec, the app automatically sizes up to the next compliant conductor, conduit, or device. You see the answer and you see why.
58+ CALCULATORS FOR THE WORK YOU DO
Voltage drop, conduit and box fill, motor branch circuit sizing, service and feeder load calculations (NEC 220), grounding electrode conductors, equipment grounding, and bending math. Enter what you know. Get the answer. Move on.
WORKS WHERE YOU WORK
No network. No account. No cloud dependency. Sparky's Black Book is 100% on-device. It runs the same in a basement with zero bars as it does in your truck.
FREE TO USE
The calculators, conduit bending, torque specs, the Black Book reference tables, OSHA safety reference, and the built-in level, compass, and flashlight are all free.
SPARKY PRO
Upgrade to Sparky Pro to unlock the heavy-duty field tools:
- Field Lab: motor nameplate OCR scanner, AR tape measure, and Voice Calc
- Job Pack Generator: compile calcs, photos, and docs to a shareable PDF
- BOM Builder: materials, quantities, and pricing with save and export
- Time & Notes: GPS-tagged clock in and out logging
Sparky Pro is an auto-renewable subscription:
- Monthly: $4.99 per month
- Yearly: $29.99 per year
Payment is charged to your Apple Account at confirmation of purchase. The subscription renews automatically unless canceled at least 24 hours before the end of the current period. Your account is charged for renewal within 24 hours prior to the end of the current period. You can manage or cancel your subscription in your Apple Account settings after purchase.
Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://www.capitolsafetytechnologies.com/privacypolicy
BUILT FOR THE JOB SITE
The hi-vis fluorescent theme is readable in truck bays, crawlspaces, attics, and direct sunlight. Touch targets are sized for gloves. Every screen gets you to the calc you need in two taps or less.
If you're a journeyman, master electrician, or apprentice doing real commercial, industrial, or residential work, this is the calc tool you put on your phone and trust on every job.
Introducing Sparky Pro — unlock Field Lab (nameplate OCR, AR tape measure, Voice Calc), Job Pack PDF export, BOM Builder, and GPS time tracking. All 58+ calculators and the NEC reference tables remain free. Plus stability and accuracy improvements.
The developer, Chris Snider, 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
- Chris Snider
- Size
- 15.2 MB
- Category
- Utilities
- Compatibility
Requires iOS 18.0 or later.
- iPhone
Requires iOS 18.0 or later. - iPad
Requires iPadOS 18.0 or later. - Mac
Requires macOS 15.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 2.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Sparky's Black Book