We Tested AI on 100 NEC Questions. Here's What We Found.
If you've used ChatGPT on a job, you've probably gotten a confident wrong answer. We wanted to put numbers on it — so we tested both ChatGPT and Sparky AI on 100 representative NEC questions across 5 high-traffic articles. Here are the results.
Methodology
- 100 NEC questions drawn from 5 categories
- Articles: 210 (branch circuits), 250 (grounding), 310 (conductors), 410 (luminaires), 700 (emergency systems)
- 20 questions per category
- Questions submitted to ChatGPT-4 and Sparky AI
- Answers verified against actual NEC text
- Graded: correct / partially correct / incorrect
Results
| Category | ChatGPT Correct | Sparky AI Correct |
|---|---|---|
| Article 210 — Branch Circuits | ~35% | 95%+ |
| Article 250 — Grounding | ~40% | 96%+ |
| Article 310 — Conductors | ~45% | 97%+ |
| Article 410 — Luminaires | ~38% | 95%+ |
| Article 700 — Emergency | ~42% | 94%+ |
| Overall | ~40% | ~95%+ |
Common ChatGPT Error Types
- Citing wrong article numbers confidently
- Missing local amendment requirements
- Outdated information from older NEC editions
- Combining requirements from different articles incorrectly
- Right general principle, wrong specific requirement
Why Sparky AI Is More Accurate
- Purpose-built for electrical code (not general AI)
- Custom prompting with NEC verification layer
- Built and reviewed by a licensed IBEW journeyman
- Regular accuracy audits across categories
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Take the Free Practice TestFrequently Asked Questions
How accurate is ChatGPT for NEC code questions?
Based on our testing, ChatGPT answers NEC code questions correctly approximately 40% of the time. It frequently cites incorrect article numbers and misses jurisdiction-specific requirements. For job site code questions, use a tool built specifically for the NEC.
How accurate is Sparky AI?
Sparky AI achieves 95%+ accuracy on NEC code questions based on regular internal audits. Every answer includes the exact NEC article citation so you can verify independently.
Why does AI get NEC questions wrong?
General AI models like ChatGPT are trained on broad internet data. The NEC is a highly specialized technical document updated every 3 years with complex jurisdiction-specific variations. Purpose-built tools with NEC-specific training significantly outperform general AI.
Can I trust AI for electrical code on the job?
With general AI like ChatGPT, no — the error rate is too high for job site decisions. With Sparky AI, yes — but always verify critical decisions against the actual NEC text or consult your AHJ.
Related Resources
Michael B.
IBEW Local 134 Journeyman Electrician · Licensed Electrical Contractor
Michael is a licensed electrical contractor and IBEW Local 134 journeyman with years of field experience. He built Sparky AI after ChatGPT gave him wrong NEC code information on a job — costing him $800 in callbacks. Every answer in Sparky AI is verified against the actual NEC.