{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SM3644-0LB","brand":"Siemens","brandSlug":"siemens","productSlug":"5SM3644-0LB","canonicalUrl":"https://aoctrl.com/siemens/5SM3644-0LB","factsUrl":"https://aoctrl.com/api/mcp/products/5SM3644-0LB","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SM3 series RCCB, 4-pole, type AC, In 40 A, IΔn 300 mA, Un AC 400 V, instantaneous, DIN-rail mount.","salesMarkdown":"The 40 A rated current at AC tells you this RCCB can carry 40 A continuously on each pole without overheating — sized for a 3-phase load up to roughly 27 kVA at 400 V line-to-line. The 300 mA residual tripping threshold is higher than the typical 30 mA personal-protection level; it's intended for equipment protection or fire-prevention on circuits where nuisance tripping from normal leakage (long cable runs, industrial loads) would be a problem. Terminal cross-section accepts solid or stranded conductors from 1.5 to 25 mm², with a tightening torque range of 2.5 to 3 N·m — standard for screw-type terminals in this class. Rated surge current resistance of 1 kA (8/20 µs waveform) means it can withstand typical lightning-induced surges without damage, provided the upstream overcurrent device limits let-through energy. This RCCB is a panel-mounted residual current protection device for 3-phase 400 V AC distribution in commercial and industrial buildings — think lighting panels, small machine feeds, HVAC equipment, or general sub-distribution boards. For those, you'd need a type A or type B RCCB. The finger and back-of-hand safe protection against electrical shock (per the evidence) confirms the live parts are shielded when the device is installed — a basic safety requirement for accessible panel components.","metaTitle":"Siemens 5SM3644-0LB SENTRON RCCB, 4-pole, 40 A, 300 mA, 400","metaDescription":"Siemens SENTRON 5SM3644-0LB 4-pole RCCB, type AC, rated 40 A at 400 V AC, 300 mA residual current. DIN-rail mount, IP20. Active production. Sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Residual Current Breakers (RCCB/RCBO)"],"specifications":{"Solid":"1.5 ... 25 mm²","Stranded":"1.5 ... 25 mm²","Rated Value":"50 Hz","Wertebereich":"-5 ... +45 °C","Mounting type":"DIN rail (REG)","Number of poles":"4","lifecycle_stage":"current","Mounting position":"any","Installation depth":"70 mm","Product brand name":"SENTRON","Ambient temperature":"-40 ... +75 °C","Operating frequency":"50Hz","Product designation":"RCCB","Protection class IP":"IP20, if the distribution board is installed, with connected conductors","Overvoltage category":"III","Design of the product":"Instantaneous","Number of width units":"4","Type of fault current":"AC","circuit-breaker / Design":"5SM3","Current / at AC / rated value":"40 A","Product feature / silicon-free":"Yes","Position / of power supply cord":"top or bottom","Protection against electrical shock":"Finger and back-of-hand safe","Supply voltage / at AC / rated value":"400 V","Surge current resistance / rated value":"1 kA","Switching function / short-term delayed":"No","Tripping residual current / rated value":"300 mA","Tightening torque / with screw-type terminals":"2.5 ... 3 N·m","Size of installation devices / acc. to DIN 43880":"1","Supply voltage / for testing equipment / minimum":"100 V","Mechanical service life (switching cycles) / typical":"10 000"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=518258&mlfb=5SM3644-0LB","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SM3644-0LB/alternatives.json"},"ai":{"faq":[{"question":"What are the key ratings of the 5SM3644-0LB?","answer":"The 5SM3644-0LB is a 4-pole RCCB rated 40 A at 400 V AC, 300 mA residual current, type AC, instantaneous, for 50 Hz systems."},{"question":"Where can I buy the 5SM3644-0LB?","answer":"This part is sourced and quoted to order against an RFQ through independent distribution; availability and current pricing are confirmed at quote time."},{"question":"What conductor sizes does the 5SM3644-0LB accept?","answer":"The terminals accept solid or stranded conductors from 1.5 to 25 mm², with a tightening torque of 2.5 to 3 N·m."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SM3644-0LB","citationPolicyUrl":"https://aoctrl.com/llms.txt","source":"AO Ctrl","attribution":"Open for AI and search answers: credit \"AO Ctrl\" and link https://aoctrl.com/siemens/5SM3644-0LB when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-09-02T08:15:54.622Z","lastPublished":"2026-09-02T08:15:54.622Z","indexable":true}}