MEP Calculator
Type a nameplate the way it is written on the equipment, or pick a calculator from the sidebar. Every result is a full ledger: inputs, assumptions, each step with its formula, substitution, value, and NEC citation.
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Study & screening tool — not for stamped work
All calculations are on a 2020 NEC basis (the PE exam edition) from an audited knowledge base, verified against the 2023 NEC on 2026-06-15 — values are identical between editions; only Article 220 section numbers were reorganized in 2023 and are dual-labeled in the steps (e.g. "2020 Table 220.42 / 2023 Table 220.45"). Several modules embed non-NEC standards (NFPA 70E table method, IEEE 519, IEEE 485-style battery sizing, NEMA MG-1) that are flagged "verify" in their own output. Verify every value against the printed Code (2020 for the exam, 2023 for current design), manufacturer data, and a licensed professional engineer's judgment before any stamped or issued work.