7 corrections on record · 1 safety-relevant · newest first
Every NEC value in OhmBase is transcribed from the printed book and checked against it before it ships. When an error is found anyway, it is fixed in the source tables, pinned by a regression test so it cannot come back, and logged here with what was wrong, what changed and which results to re-check. Users are told inside the app (Profile → About) — nothing is patched quietly.
Calculator results show their sources: every figure carries the table or section it came from, and tapping it opens that entry in the app.
2026-09-10 · fixed in v4.5.9 · NEC reference · Reference text only
The electric-vehicle supply equipment entry described the load as nameplate only. NEC 220.57 requires the larger of 7,200 VA or the nameplate rating. Reference text only — no calculator used it.
Verified against: NEC 2023, 220.57
Affected versions: v4.5.8 and earlier (reference text)
2026-09-10 · fixed in v4.5.9 · NEC reference · Reference text only
The SPD entry cited Article 280, which was renumbered to Article 242 in the 2020 NEC. Reference text only — no calculator used it.
Verified against: NEC 2023, Article 242
Affected versions: v4.5.8 and earlier (reference text)
2026-07-16 · fixed in v4.3.6 · Motor wiring · Sizing result changed
The motor tool picked the conductor from a separate hard-coded amps-to-AWG list that did not match Table 310.16 — 50 A returned 3 AWG where the 75 °C copper column puts 8 AWG at 50 A. The tool now reads Table 310.16 directly, with no parallel list to drift. Results were larger than required, never smaller.
Verified against: NEC 2023, Table 310.16 (75 °C copper)
Affected versions: v4.3.5 and earlier
2026-07-15 · fixed in v4.3.4 · Wire pulling · Sizing result changed
The jam-ratio check in the wire-pulling tool used EMT internal diameters for rigid conduit. Corrected to Chapter 9 Table 4 (½" 0.632 in through 3" 3.090 in). EMT values were already correct.
Verified against: NEC 2023, Chapter 9 Table 4
Affected versions: v4.3.3 and earlier
2026-07-15 · fixed in v4.3.3 · Raceway sizing · Sizing result changed
Three Chapter 9 Table 5 areas mixed insulation families. Corrected: 3 AWG → 0.0973 sq in, 2 AWG → 0.1158 sq in, 400 kcmil → 0.5863 sq in. All other sizes were already correct.
Verified against: NEC 2023, Chapter 9 Table 5
Affected versions: v4.3.2 and earlier
2026-07-15 · fixed in v4.3.2 · Raceway sizing · Sizing result changed
IMC held a copy of the PVC column and rigid (RMC) was undersized; EMT was already correct. Every raceway area was re-transcribed from Chapter 9 Table 4 and triple-checked (π/4 × ID² = the printed 100% area = the printed 40% area ÷ 0.4).
Verified against: NEC 2023, Chapter 9 Table 4
Affected versions: v4.3.1 and earlier
2026-07-15 · fixed in v4.3.0–v4.3.1 · Motor wiring · Safety-relevant
115 V and 230 V single-phase full-load currents did not match Table 430.248 — a ½ HP 115 V motor read 4.4 A instead of 9.8 A, so the wire, breaker, overload and disconnect figures built on it were all too small. The 1/6, 1/4 and 1/3 HP rows were added at the same time. Three-phase motor data (Table 430.250) was not affected.
Verified against: NEC 2023, Table 430.248
Affected versions: v4.2.5 and earlier
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