U.S. code adoption
Montana — energy & appliance code adoption
Yes — effectively. This page summarizes electrical (NEC), appliance-listing (UL 858), fire-code, and energy-storage (UL 9540 / NFPA 855) code adoption for Montana, with primary sources.
Is UL 858 required in Montana?
Yes — effectively. Montana requires fixed household appliances to be listed by a Nationally Recognized Testing Laboratory (NRTL), and UL 858 is the de-facto listing standard a household electric range must meet.
Are NRTL-listed (UL / ETL / CSA) appliances required in Montana?
Yes. Montana's adopted code requires fixed electrical appliances to be listed by an NRTL (UL, ETL/Intertek, CSA, etc.) — NEC 110.3.
Which edition of the NEC does Montana use?
Montana has adopted the 2020 edition of the National Electrical Code (NEC), effective 2022-06-11.
Is UL 9540 required for residential energy storage in Montana?
Yes — effectively. Montana requires NRTL listing for stationary energy storage systems (ESS) in dwellings, and UL 9540 is the controlling standard. ESS in residential dwellings governed by IFC §1207, referencing UL 9540 listing and NFPA 855 installation standard. UL 9540A required to exceed the default 20 kWh / dwelling cap or reduce default 3-ft separation.
Is UL 9540A fire-propagation testing required in Montana?
Yes — effectively. Montana requires NRTL listing for energy storage systems, and UL 9540A is the controlling standard.
What is the residential energy-storage capacity limit in Montana?
Montana limits residential energy storage to 20 kWh per dwelling unit.
Which fire code does Montana enforce?
Montana enforces IFC 2021. Montana Fire Code (ARM 23.12.601) based on IFC 2021, effective March 11, 2023.
Code adoption summary
| NEC edition | 2020 NEC |
|---|---|
| Appliance listing (UL 858) | Effectively required |
| NRTL listing requirement | Required |
| Fire code | IFC 2021 |
| IRC edition | 2021 IRC |
| UL 9540 (residential ESS) | Effectively required |
| UL 9540A propagation test | Effectively required |
| Residential ESS cap | 20 kWh / dwelling |
| NFPA 855 edition | 2020 |
Sources
- NFPA — NEC enforcement maps
- Montana Building Codes Bureau — Current Codes
- ARM 23.12.601 — Adoption of the International Fire Code (2021 Edition)