# 509 Box Fill: NEC 314 — NEC Box Fill Calculator

> NEC Box Fill Calculator (iPhone/iPad app by Nicole Nalley.)

- Source: https://appshunter.io/ios/app/509-box-fill-nec-314/id6772603330 (this page in markdown: same URL + `.md`)
- Developer: [Nicole Nalley](https://appshunter.io/developer/1894562817)
- Category: Utilities, Productivity
- Price: Free
- Age rating: 4+
- Requires: iOS 15.0 · 2 MB
- Languages: American English
- Released: 2026-10-10
- Data updated: 2026-10-13

## What is 509 Box Fill?

Calculate box fill per NEC 314.16 and pull/junction-box minimum dimensions per NEC 314.28 in seconds. 509 Box Fill is a fast, local-first field calculator built for electricians, journeymen, and apprentices.

Enter conductor counts, clamp and device allowances, and equipment grounds to get the required cubic-inch fill and pass/fail status against a standard or custom box volume. Switch to Min Box to find the smallest standard box that fits. Use Pull Box to calculate minimum box dimensions for straight and angle/U-pull raceway entries.

Designed for quick use:

• NEC 314.16(B) conductor volume allowances
• NEC 314.16(A) standard box volumes with pass/fail result
• Min Box recommends the smallest standard box that fits
• NEC 314.28 pull and junction box sizing for straight and angle/U pulls
• Light and dark mode
• Suite accent color picker
• NEC reference citations on every work line
• Local-first settings; no account or sign-in required

509 Box Fill is a field calculator. Always verify against the NEC adopted in your jurisdiction.

## Is 509 Box Fill safe?

Not enough ratings yet to assess 509 Box Fill.

## Is 509 Box Fill legit?

509 Box Fill: NEC 314 appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for 509 Box Fill is 65 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 1 release)

### 1.2.1 — 2026-10-11

No release notes.

## More apps by Nicole Nalley

- [509 Electric](https://appshunter.io/ios/app/509-electric/id6762534343)
- [Truebend: Conduit Bending](https://appshunter.io/ios/app/truebend-conduit-bending/id6770817660)
- [TruePhase: Wire Color Codes](https://appshunter.io/ios/app/truephase-wire-color-codes/id6771228149)
- [TrueFault: Fault Current Calc](https://appshunter.io/ios/app/truefault-fault-current-calc/id6772432318)
- [TrueOhm](https://appshunter.io/ios/app/trueohm/id6772605137)

All apps by Nicole Nalley: https://appshunter.io/developer/1894562817

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-13.*