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What code article in the NEC requires an emergency disconnect for What size generator
Executive Summary
The National Electrical Code requires additional emergency shutdown provisions for stationary generators rated greater than 15 kW under Article 445.18, including a remote emergency stop outside the generator room for non‑dwelling installations; for one‑ and two‑family dwellings, a separate outdoor emergency disconnect requirement appears under Article 230.85 without a kW threshold [1] [2] [3]. These different provisions mean compliance depends on both generator rating and occupancy type; installers and authorities having jurisdiction must read Article 445 alongside 230.85 to determine exact labeling, location, and short‑circuit rating obligations [4] [5].
1. Why the 15 kW Threshold Changed the Conversation and What It Actually Says
Analyses drawn from multiple NEC‑focused summaries converge on a clear, specific requirement: Article 445.18 requires an emergency disconnect or remote shutdown for generators rated above 15 kW, with the remote stop typically located outside the generator enclosure or equipment room and labeled appropriately [2] [1] [4]. The requirement applies to nonportable generators and aims to provide a readily accessible means to stop the prime mover in emergencies; the disconnecting means must be capable of being locked in the open position in some circumstances, and the remote switch must meet Section 110.21(B) labeling standards according to the analyses [2] [6]. This places the obligation on larger standby and backup systems commonly used in commercial or multi‑family settings.
2. A Different Rule for Small Homes: The 230.85 Emergency Disconnect That’s About Location, Not kW
Separate analyses highlight Article 230.85, which mandates an outdoor, readily accessible emergency disconnect for one‑ and two‑family dwellings and focuses on the disconnect’s short‑circuit current rating relative to the available fault current rather than a generator kW threshold [3] [5]. In practical terms, a homeowner’s standby generator installation may trigger Article 230.85’s outdoor disconnect requirement regardless of generator size, while Article 445’s >15 kW threshold may not apply to small residential units. The distinction is important because 230.85 frames the obligation by occupancy type and accessibility, obliging installers to ensure the outdoor device is rated correctly and clearly accessible.
3. Where the Analyses Agree — and Where They Diverge — on Location, Labeling, and Locking
Across the provided analyses, there is consensus on several operational details: emergency shutdowns for applicable generators must be readily accessible, labeled “Generator Emergency Shutdown” or similarly, and in some cases lockable in the open position [2] [6] [4]. The divergence is primarily about scope: some summaries emphasize Article 445 for generators over 15 kW [1] [4], while other excerpts underscore an occupancy‑based outdoor disconnect requirement in 230.85 for single‑family dwellings with no explicit kW limit [3] [5]. This duality means both the generator’s rating and the building type must be evaluated; neither article supersedes the other outright, and both can apply depending on the installation facts.
4. Source Dates, Provenance, and Potential Agendas to Watch
Two of the provided analyses carry 2025 timestamps (p1_s3 dated 2025‑02‑07 and [4] dated 2025‑03‑18), indicating the summaries reflect recent NEC interpretations or code‑change reporting through early 2025. Other entries lack explicit publication dates but are framed as NEC commentary or trade‑forum explanations [2] [6] [5]. Trade and training organizations that produce NEC guidance can emphasize practical compliance tips and may simplify distinctions for audiences; that emphasis can appear as an agenda to drive training or product sales. Readers should note the mix of forum, blog, and code‑summary types among the sources and verify with the official NEC text and the authority having jurisdiction.
5. Practical Implications for Installers, AHJs, and Homeowners on the Ground
For designers and installers, the combined message is clear: determine both the generator rating and the occupancy classification before choosing compliance strategies. If the generator is over 15 kW and not portable, Article 445’s emergency stop requirements apply, including a labeled remote stop outside the equipment room and lock‑open capability where specified [2] [4]. If the installation is a one‑ or two‑family dwelling, ensure an outdoor, readily accessible disconnect meeting short‑circuit rating requirements per Article 230.85, regardless of generator kW [3]. Authorities having jurisdiction must interpret overlapping requirements locally and may require the most restrictive provision.
6. Bottom Line: How to Verify Compliance Quickly and Safely
To confirm the correct requirement for any given installation, consult the current NEC text for Articles 445.18 and 230.85, cross‑check local amendments, and document the generator’s rated kW and the building occupancy. Use the Article 445 >15 kW rule as the trigger for remote emergency shutdown hardware in non‑dwelling contexts and Article 230.85 for outdoor disconnects on one‑ and two‑family dwellings; ensure labeling, short‑circuit ratings, and accessibility match the cited provisions [1] [5] [6]. When in doubt, contact the local authority having jurisdiction — the NEC provides the framework, but local enforcement determines the final compliance path.