Which code your Massachusetts project is actually inspected against
The governing document is the Massachusetts State Building Code, 780 CMR, 10th Edition, effective 11 October 2024 and based on the 2021 I-Codes; Chapter 51 adopts the 2021 IRC for residential work. Electrical work follows 527 CMR 12.00, which adopts the 2026 National Electrical Code with effect from 24 April 2026 — worth checking against, because secondary code mirrors online still show the 2023 text. In Boston itself, the permitting authority for building, electrical, plumbing and gas is the Inspectional Services Department, under M.G.L. c.143 §§3 and 3A.
Two licences are not optional on our kind of work: a Massachusetts-licensed electrician (M.G.L. c.141 §3) and a Massachusetts-licensed plumber (c.142 §3, 248 CMR 10.00). On listing, there is no Massachusetts-specific rule forcing a particular testing laboratory — 527 CMR 12.00 Rule 6 is permissive — but the hard requirement sits in federal law at OSHA 29 CFR 1910.303(a) and 1910.399, which is why we specify UL- or ETL-listed equipment rather than relying on a CE mark.