# NEC 690 Reference — 60 NEC articles + calculators

> 60 NEC articles + calculators (iPhone/iPad app by Rizvan Adzhoian.)

- Source: https://appshunter.io/ios/app/nec-690-reference/id6767839064 (this page in markdown: same URL + `.md`)
- Developer: [Rizvan Adzhoian](https://appshunter.io/developer/1891746079)
- Category: Utilities, Business
- Price: $0.99 with in-app purchases
- Age rating: 17+
- Requires: iOS 13.0 · 33 MB
- Languages: American English
- Released: 2026-05-12
- Data updated: 2026-09-08
- User reviews in markdown: https://appshunter.io/ios/app/nec-690-reference/id6767839064/reviews.md

## What is NEC 690 Reference?

NEC 690 Reference is a study and field companion for solar photovoltaic professionals working under the National Electrical Code Articles 690, 691, 705, 706, and 710. Everything is paraphrased educational summary — designed for quick lookups, exam practice, and inspection prep, fully offline.

WHAT IS INSIDE

- 60 NEC section summaries across Articles 690 (PV Systems), 691 (Large-Scale PV), 705 (Interconnection), 706 (Energy Storage), and 710 (Stand-Alone Systems)
- 31 plain-language definitions of NEC terms (PV source circuit, PV output circuit, MPPT, rapid shutdown, AHJ, NRTL, qualified person, listed, labeled, and more)
- 10 step-by-step worked examples with numbers and conclusions: cold-temperature Voc, PV source current sizing, voltage drop, conductor temperature derating, OCPD selection, conduit fill, inverter AC sizing, 120% rule, EGC sizing, breaker selection
- 25 NABCEP-style practice quiz questions with explanations and NEC citations
- 3 inspection checklists (pre-install, mid-install, final inspection) with 16+ checkpoints each, anchored to specific NEC sections
- 4 quick reference tables: standard breaker sizes, copper ampacity (75 / 90 C), aluminum ampacity (75 / 90 C), and copper conductor resistance per 1000 ft
- 13 code-change entries highlighting differences between NEC 2017, 2020, and 2023 for the major solar-related sections

5 IN-APP CALCULATORS

- Cold-Temperature Voc — adjusts module Voc for the lowest expected ambient and reports the maximum string length under the inverter max DC voltage (NEC 690.7)
- PV Source Circuit Current — applies the 1.25 x 1.25 factor for conductor and OCPD sizing (NEC 690.8 and 690.9)
- Voltage Drop — AC single phase, AC three phase, and DC; copper or aluminum; AWG 14 to 4/0
- Conduit Fill — EMT, RMC, and PVC Schedule 40; THWN-2, XHHW-2, and PV Wire; warns when fill exceeds 40 percent
- Breaker Size — selects the next standard NEC 240.6 ampere rating for continuous or non-continuous loads

DESIGNED FOR

- Solar PV installers and electricians
- Electrical engineers and PV designers
- Building inspectors and plan reviewers
- Apprentices and NABCEP candidates studying for certification

IMPORTANT

All content is an original paraphrased educational summary. This app is not a substitute for the official NEC or any certification exam materials. Always consult the latest published NEC and the local Authority Having Jurisdiction for legal requirements.

OPTIONAL PRO UPGRADE — $2.99 ONE-TIME IN-APP PURCHASE

The following features require a separate one-time in-app purchase. They are not required to use any of the calculators or content above:

- Unlimited article views with no daily limit
- Dark theme
- Ad-free experience

Contact: support@tradetools.dev

## Pricing and in-app purchases

Base price: $0.99.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Pro Unlock | $2.99 | one-time |



## Version history (last 2 releases)

### 1.1.1 — 2026-05-14

- Fixed cross-app links: tapping another SolarTools app in More Tools now opens its App Store page on iPhone and iPad.
- Minor stability improvements.

### 1.0.0 — 2026-05-12

No release notes.

## More apps by Rizvan Adzhoian

- [Conduit Fill Calculator-NEC](https://appshunter.io/ios/app/conduit-fill-calculator-nec/id6761846849)
- [Electrical Load Calc NEC](https://appshunter.io/ios/app/electrical-load-calc-nec/id6763250945)
- [Transformer Calc NEC](https://appshunter.io/ios/app/transformer-calc-nec/id6763311943)
- [Voltage Drop Calc NEC](https://appshunter.io/ios/app/voltage-drop-calc-nec/id6763312448)
- [Grounding Size Calc NEC](https://appshunter.io/ios/app/grounding-size-calc-nec/id6763312724)
- [Breaker Size Calc NEC](https://appshunter.io/ios/app/breaker-size-calc-nec/id6763312865)

All apps by Rizvan Adzhoian: https://appshunter.io/developer/1891746079

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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 2026-09-08.*