Multi-NEC-Edition Support

Different AHJs (Authorities Having Jurisdiction) adopt different editions of the NEC on different schedules. As of 2026, some jurisdictions still enforce NEC 2017 or 2020, while others have adopted 2023 or 2026. An electrician working across jurisdictions may need to perform calculations under three or four different editions in the same week.

Using the wrong edition is a common source of inspection failures and permit rejections. A load calculation performed under NEC 2026 (Article 120, 2 VA/sq ft lighting) will produce a different result than the same calculation under NEC 2023 (Article 220, 3 VA/sq ft lighting).

Key values that change between editions:

• General lighting load: 3 VA/sq ft (2017–2023) vs. 2 VA/sq ft (2026)
• Load calculation article: Article 220 (2017–2023) vs. Article 120 (2026)
• Optional method threshold: 10,000 VA at 100% (2017–2023) vs. 8,000 VA at 100% (2026)
• EV charger provisions: Simplified in 2026 NEC
• PCS (Power Control Systems): Formally recognized in 2026 NEC (Article 750)
• Removed load credit: New Section 120.87 in 2026 NEC
• Table numbers: Various tables renumbered in 2026 (Table 220.42 → Table 120.42, etc.)

When you select an NEC edition, every calculation in the session uses that edition’s tables, article numbers, and values. The edition is displayed as a badge on every output: “Calculated per NEC 2026.”

When a result differs between editions, the calculator shows both values with the delta: “General lighting: 2 VA/sq ft (NEC 2026) vs. 3 VA/sq ft (NEC 2023) — 33% reduction.”

When you search for an article number, the calculator cross-references between editions: “Article 220 (NEC 2023) = Article 120 (NEC 2026).”

Project-level edition locking prevents accidentally mixing editions within a single job.