NEMA 3R Service Entrance Disconnect Switches

A service entrance disconnect is the main shutoff device located at the point where utility power enters a building or facility. It allows utility workers and electricians to safely de-energize the entire electrical system. Per NEC requirements, it must be located at a readily accessible point nearest to where the service conductors enter the building, and can be a circuit breaker, fused switch, or switchgear assembly.

The National Electrical Code (NEC) Article 230 governs service entrance disconnects. It requires that the disconnecting means be installed at a readily accessible location, either outside the building or inside nearest the point of entry of service conductors. The NEC also limits the number of disconnects to six and mandates that all disconnects be grouped together. Local utility requirements and EUSERC standards may impose additional specifications.

DEI Power's NEMA 3R service entrance disconnect switches are available in amperage ratings of 400A, 600A, 800A, 1000A, 1200A, 1600A, 2000A, 2500A, 3000A, and 4000A. This wide range accommodates everything from mid-size commercial buildings to large industrial plants and utility infrastructure projects requiring high-capacity power distribution.

Our NEMA 3R service entrance products support multiple voltage configurations including 120/240V, 240V, 208Y/120V, 240/120V, 480V, 480Y/277V, and 415/240V. This flexibility ensures compatibility with a broad range of utility service types and facility electrical systems across commercial, industrial, and utility applications throughout the USA.

Yes. Due to utility standards, all service entrance switchgear — including meter mains, SES sections, and service entrance switchgear — must be built to approved utility specifications. DEI Power is EUSERC approved and works with utility requirements to ensure each assembly meets the specific standards of the serving utility. Customers should call a specialist before placing an order to confirm specifications.

Yes. DEI Power's NEMA 3R service entrance disconnect assemblies meet UBC, CBC, and IBC requirements for all seismic zones. This makes them suitable for installation in earthquake-prone regions such as California and other areas with strict structural and seismic compliance mandates for electrical equipment mounted in commercial and industrial facilities.