{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SM2645-2","brand":"Siemens","brandSlug":"siemens","productSlug":"5SM2645-2","canonicalUrl":"https://aoctrl.com/siemens/5SM2645-2","factsUrl":"https://aoctrl.com/api/mcp/products/5SM2645-2","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON selective RCD unit, 4-pole, type AC, In 63 A, IΔn 300 mA, Un AC 400 V, 50 Hz, 3 MW, IP20.","salesMarkdown":"## RCD unit for selective earth-fault protection The Siemens SENTRON 5SM2645-2 is a 4-pole selective residual current device (RCD) rated 63 A at 400 V AC, 50 Hz, with a fixed trip threshold of 300 mA, type AC. Selective design means it delays tripping to coordinate with downstream RCDs — only the faulted branch clears, keeping the rest of the distribution board live. The 300 mA rated fault current is not adjustable, and the OFF-delay time is fixed — this is intentional for the selective role: it sits at the supply side of a sub-distribution board, coordinating with 30 mA RCDs downstream. Type AC means it detects sinusoidal AC residual currents only; if the installation includes non-sinusoidal waveforms (rectifiers, VFDs), a type A or B RCD would be required. Insulation voltage is rated 460 V, overvoltage category III, pollution degree 2 — standard for fixed-installation distribution boards in commercial and industrial buildings. Surge voltage withstand is 4 kV, which matches the impulse voltage expected at the service entrance of a building. IP20 is the protection class with conductors connected and the distribution board installed — meaning the front face is touch-safe, but the unit is not sealed against moisture or dust ingress. Supply can enter from top or bottom; the unit is not sealable (no provision for a lead seal on the adjustment cover).","metaTitle":"Siemens SENTRON 5SM2645-2 RCD Unit, 63 A, 300 mA, 4-pole","metaDescription":"Siemens SENTRON 5SM2645-2 selective RCD unit, 4-pole, type AC, 63 A rated current, 300 mA fault current, 400 V AC. Current lifecycle stage. 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":{"title":"5SM2645-2","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"No","description":"RC unit, 4-pole, type AC, selective, In: 63 A, 300 mA, Un AC: 400 V","Design Of Pole":"4 poles","Number Of Poles":"4","lifecycle_stage":"current","Fastening Method":"REG","Mounting Position":"any","at AC rated value":"63 A","Installation Depth":"70 mm","Product Brand Name":"SENTRON","Product Variations":"for 5SY","Degree Of Pollution":"2","Product Designation":"RCD-unit","protection class IP":"IP20, if the distribution board is installed, with connected conductors","Overvoltage Category":"III","Design Of The Product":"Selective","Residual Current Type":"AC","OFF-delay time adjustable":"No","For Testing Equipment Minimum":"195 V","Number Of Modular Width Units":"3","Position Of Power Supply Cord":"top or bottom","Rated Fault Current Adjustable":"No","Protection Function False Tripping":"Yes","Tripping Fault Current Rated Value":"300 mA","insulation voltage (Ui) rated value":"460 V","Surge Voltage Resistance Rated Value":"4 000 V","Value Range Of The Operating Frequency":"50 Hz","Type Of Voltage Of The Operating Voltage":"AC","Value Range Of The Supply Voltage Frequency":"50 Hz","Mechanical Service Life (Operating Cycles) Typical":"10 000","for rated value of the current at AC in hot operating state per pole":"3 W"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/9573be1ea44e598cde853d827d10c350.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=390744&mlfb=5SM2645-2"},"ai":{"faq":[{"question":"What is the 5SM2645-2 used for?","answer":"It is a selective 4-pole RCD for 3-phase 4-wire AC systems, rated 63 A / 300 mA, designed to provide earth-fault protection with time delay so that downstream RCDs trip first, localizing the fault."},{"question":"What are the key ratings of the 5SM2645-2?","answer":"Rated current 63 A, rated fault current 300 mA (fixed, type AC), operating voltage 400 V AC at 50 Hz, insulation voltage 460 V, overvoltage category III, pollution degree 2, operating temperature -40 °C to 75 °C."},{"question":"Where can I buy the 5SM2645-2?","answer":"This part is sourced and quoted to order against an RFQ through independent distribution channels. Availability and current pricing are confirmed at the time of quotation."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SM2645-2","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/5SM2645-2 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:51:03.652Z","lastPublished":"2026-08-11T15:51:03.652Z","indexable":true}}