ABB S401M-UCC25

Technical Dossier

Product Details And Specifications

ABB S401M Series Technical Notes

The ABB S401M series belongs to the System Pro M Compact® product family — a line of modular, DIN-rail-mounted miniature circuit breakers (MCBs) engineered for high-performance overcurrent protection in industrial and commercial power distribution systems. Deployed globally across chemical processing plants, oil refineries, nuclear auxiliary systems, and heavy manufacturing facilities, the S401M range is a standard reference component in low-voltage switchgear panels rated up to 400V AC. Its 4-pole configuration makes it the preferred choice for three-phase-plus-neutral applications where simultaneous disconnection of all live conductors is required by IEC 60898-1 and IEC 60947-2 standards. The series is characterized by a compact 70mm installation depth, high breaking capacity variants (up to 25kA at 400V AC), and compatibility with ABB's extensive accessory ecosystem including auxiliary contacts, shunt trips, and undervoltage releases.

The Evolution of S401M Architecture

The S401M series represents the high-breaking-capacity tier within ABB's 4-pole MCB portfolio, succeeding earlier S4 and S400 platform generations. The original S400 series established the physical form factor and DIN-rail pitch standard still used today. The S401M designation introduced an enhanced magnetic-thermal trip mechanism with tighter tolerance bands, improving coordination selectivity in cascaded protection schemes. The suffix codes encode the trip characteristic and rated current: B (3–5× In, general wiring), C (5–10× In, standard motor/inductive loads), D (10–20× In, high-inrush transformers and solenoids), and K (8–14× In, precision equipment). The UCC suffix specifically denotes the UL/CSA-certified variant for North American market compliance, with UCC25 indicating a 25A rated current. Compatibility with legacy S400 accessories is maintained at the mechanical interface level, though electrical ratings must be independently verified. As of 2024, the S401M series is in the mature phase of its lifecycle; ABB continues to manufacture and support the range, but engineers specifying new installations are directed toward the S800 series for applications requiring higher breaking capacity above 25kA.

S401M Full Catalog & Functionalities (SKU List)

The following SKUs represent verified, commonly stocked models within the ABB S401M 4-pole miniature circuit breaker series. All are rated for 400V AC, 4-pole configuration, DIN-rail mount, IEC 60898-1 compliant unless noted.

S401M-B6: 4P MCB, B-curve, 6A, 25kA breaking capacity, general wiring protection.
S401M-B10: 4P MCB, B-curve, 10A, 25kA, low-inrush resistive load circuits.
S401M-B16: 4P MCB, B-curve, 16A, 25kA, lighting and distribution panel feeders.
S401M-B20: 4P MCB, B-curve, 20A, 25kA, sub-distribution board protection.
S401M-B25: 4P MCB, B-curve, 25A, 25kA, high-current resistive load feeders.
S401M-C6: 4P MCB, C-curve, 6A, 25kA, motor control and inductive load protection.
S401M-C10: 4P MCB, C-curve, 10A, 25kA, pump and compressor branch circuits.
S401M-C16: 4P MCB, C-curve, 16A, 25kA, standard industrial motor feeders.
S401M-C20: 4P MCB, C-curve, 20A, 25kA, HVAC and process equipment circuits.
S401M-C25: 4P MCB, C-curve, 25A, 25kA, high-inrush motor branch protection.
S401M-C32: 4P MCB, C-curve, 32A, 25kA, three-phase motor and feeder protection.
S401M-D10: 4P MCB, D-curve, 10A, 25kA, transformer primary protection, high-inrush.
S401M-D16: 4P MCB, D-curve, 16A, 25kA, solenoid valve and transformer circuits.
S401M-K6: 4P MCB, K-curve, 6A, 25kA, precision instrument and sensitive equipment.
S401M-K10: 4P MCB, K-curve, 10A, 25kA, electronic load protection, tight trip tolerance.
S401M-UCC25: 4P MCB, UL/CSA-certified variant, 25A, North American compliance, 25kA IC rating.