{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SM3645-8","brand":"Siemens","brandSlug":"siemens","productSlug":"5SM3645-8","canonicalUrl":"https://aoctrl.com/siemens/5SM3645-8","factsUrl":"https://aoctrl.com/api/mcp/products/5SM3645-8","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SM3645-8, selective RCCB, 4-pole, type A, In: 125 A, IΔn: 300 mA, Un AC: 400 V, 50 Hz, DIN rail mount.","salesMarkdown":"The Siemens SENTRON 5SM3645-8 is a 4-pole selective residual current circuit breaker (RCCB), type A, rated at 125 A and 300 mA residual sensitivity on a 400 V AC, 50 Hz network. The 'selective' design means it incorporates a short-time delay so that downstream RCCBs trip first during a ground fault — this unit stays in, keeping upstream circuits live and narrowing the outage to the faulted branch. It's sized for main or submain protection in a distribution board where coordination with downstream 30 mA or 100 mA devices is required. Rated at 125 A continuous and 400 V AC phase-to-phase, this RCCB handles the full load current of a large submain or a main switch in a commercial panel. The 300 mA residual sensitivity is intentionally higher than the 30 mA used for personal shock protection — it's meant for equipment protection and fire prevention on circuits with natural leakage, not for direct human contact. The short-circuit withstand is 10 kA per IEC 61008-1 and 1.25 kA per EN 60898; the 10 kA figure governs its installation behind a suitable upstream overcurrent device (MCB or fuse) rated to clear faults above that level. The 70 mm installation depth is the space needed behind the panel door — check gland plate clearance if the enclosure is tight. Listed as current-production. The SENTRON series is Siemens' standard distribution protection line, widely specified across European and Middle Eastern panels. ## Installation notes Silicon-free construction suits environments where silicone outgassing can contaminate contacts or optical surfaces — relevant for automotive paint lines or clean-room adjacent panels. The design accepts supplementary devices for alarm signaling or remote tripping.","metaTitle":"Siemens SENTRON 5SM3645-8 RCCB, 4P, 125A, 300mA, 400V AC","metaDescription":"Siemens SENTRON 5SM3645-8 selective RCCB, 4-pole, 125 A rated current, 300 mA residual sensitivity, 400 V AC. IP20, DIN rail mount. 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":{"Depth":"77 mm","Width":"72 mm","Height":"90 mm","Maximum":"45 °C","Minimum":"-25 °C","Number Of Poles":"4","lifecycle_stage":"current","Fastening Method":"DIN rail (REG)","Mounting Position":"any","Installation Depth":"70 mm","Product Brand Name":"SENTRON","Product Designation":"RCCB","protection class IP":"IP20, if the distribution board is installed, with connected conductors","Overvoltage Category":"III","Design Of The Product":"Selective","Product Feature Silicon-Free":"Yes","Short-Circuit Current Rating":"10 kA","Number Of Modular Width Units":"4","Position Of Power Supply Cord":"top or bottom","according to EN 60898 rated value":"1.25 kA","according to IEC 61008-1 rated value":"1.25 kA","Switching Function Short-Term Delayed":"No","Value Range Of The Operating Frequency":"50 Hz","value range of the supply voltage at AC":"400 V","Ambient Temperature During Storage Minimum":"-40 °C","Value Range Of The Supply Voltage Frequency":"50 Hz","Supply Voltage For Testing Equipment Minimum":"100 V","Mechanical Service Life (Operating Cycles) Typical":"10 000","Product Extension Installable Supplementary Devices":"Yes","for rated value of the current at AC in hot operating state per pole":"8.9 W"}},"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=456459&mlfb=5SM3645-8","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SM3645-8/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy 5SM3645-8 and how do I get a price?","answer":"This part is sourced and quoted to order against an RFQ through independent distribution. Submit a request for current pricing and availability."},{"question":"Will 5SM3645-8 drop into a panel specified around 5SL4363-7 without rewiring?","answer":"No — the 5SL4363-7 is a 3-pole miniature circuit breaker (MCB) with a 54 mm width, while the 5SM3645-8 is a 4-pole RCCB at 72 mm wide. The function, pole count, and footprint differ; they are not drop-in interchangeable."},{"question":"What is the depth of the 5SM3645-8?","answer":"The depth is 77 mm, with an installation depth of 70 mm required behind the panel door."},{"question":"What compliance documentation does Siemens provide for 5SM3645-8?","answer":"The device carries IEC 61008-1 and EN 60898 ratings, is rated overvoltage category III, and is silicon-free. Specific RoHS/REACH declarations and the EU declaration of conformity are available from Siemens' documentation portal for the SENTRON series."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SM3645-8","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/5SM3645-8 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}}