400 Amp Electrical Panels & Breaker Boxes

A 400 amp panel is rated to handle a continuous load of up to 400 amps at its designated voltage. In practice, the NEC recommends loading to no more than 80% of the rated capacity for continuous loads, which equates to approximately 320 amps. DEI Power's panels also scale up to 4,000A for larger distribution needs.

For a 400 amp service, the NEC (Table 250.66) typically requires a minimum 3/0 AWG copper or 250 kcmil aluminum grounding electrode conductor. The exact size may vary based on local codes, the grounding electrode system used, and utility requirements. Always consult a licensed electrician and your local authority having jurisdiction (AHJ) for final specifications.

A 400 amp electrical panel should carry UL Listing (typically UL 891 for switchboards and switchgear) to confirm code compliance and safety. For utility service entrance equipment, EUSERC approval is often required. DEI Power's panels are UL 891 certified, EUSERC approved, and meet UBC, CBC, and IBC seismic requirements for all seismic zones.

NEMA 1 enclosures are designed for indoor use and protect against dust and incidental contact. NEMA 3R enclosures are built for outdoor or wet locations, adding protection against rain, sleet, and ice. DEI Power offers both NEMA 1 and NEMA 3R options across its switchboard, panelboard, switchgear, SES, and meter main product lines.

Yes. All DEI Power switchboards, panelboards, service entrance switchgear, SES, and meter main products meet UBC, CBC, and IBC requirements for all seismic zones. This makes them suitable for installation in California and other high-seismic-activity regions without requiring additional seismic upgrades or engineering modifications.

DEI Power's 400 amp panels support a wide range of voltage configurations including 120/240V, 240V, 208Y/120V, 240/120V, 480V, 480Y/277V, and 415/240V. This flexibility makes them compatible with single-phase residential-commercial service, three-phase commercial, and industrial power systems across a broad range of applications.