ABB 2CDS631031R0205 BMS311B20 1P 20A 3kA B-Curve Miniature Circuit Breaker Basic M BMS Series

The ABB BMS311B20 miniature circuit breaker (MCB), catalog number BMS311B20, SKU 2CDS631031R0205, is a 1-pole, 20 A, B-curve device from the Basic M BMS series offering 3 kA breaking capacity at 230/400 V AC. Rated to both IEC 60898-1 (domestic/commercial) and IEC 60947-2 (industrial) standards, it delivers reliable overcurrent and short-circuit protection in a compact 17.5 mm wide DIN-rail-mount housing — ideal for control panels, distribution boards, and industrial automation enclosures.

Technical Specifications

Certifications & Standards

• IEC 60898-1: Miniature circuit breakers for household and similar installations
• IEC 60947-2: Low-voltage switchgear — circuit breakers for industrial applications
• IEC/EN 60664-1: Insulation coordination for equipment within low-voltage systems
• IEC/EN 60664: General insulation coordination standard for low-voltage equipment
• EN 60664: European harmonised insulation coordination standard
• IEC 60898: Circuit breakers for overcurrent protection in household and similar installations
• IEC 60947: Low-voltage switchgear and controlgear general standards framework
• CE: Conformité Européenne — compliant with applicable EU directives
• RoHS: Restriction of Hazardous Substances — free from restricted materials per EU Directive 2011/65/EU
• REACH: Registration, Evaluation, Authorisation and Restriction of Chemicals compliance
• WEEE: Waste Electrical and Electronic Equipment Directive — proper end-of-life disposal classification

Applications & Use Cases

• Overcurrent and short-circuit protection in residential and commercial distribution boards
• Industrial control panel circuit protection in automation and machinery enclosures
• Branch circuit protection for lighting, HVAC, and general-purpose loads
• Protection of cables and conductors in DIN-rail-mounted assemblies
• Compact single-pole protection where space is limited (17.5 mm pitch)