{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SM2645-8","brand":"Siemens","brandSlug":"siemens","productSlug":"5SM2645-8","canonicalUrl":"https://aoctrl.com/siemens/5SM2645-8","factsUrl":"https://aoctrl.com/api/mcp/products/5SM2645-8","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON selective RCD unit, 4-pole, 63 A, 300 mA Type A, for 5SY MCB, IP20.","salesMarkdown":"The Siemens SENTRON 5SM2645-8 is a selective RCD unit (Type A) designed to pair with a 5SY series MCB in a 4-pole configuration. Rated at 63 A with a 300 mA trip threshold, it's built for branch circuits where you need fault discrimination — the 'S' curve delay lets a downstream RCD trip first, keeping this unit from dropping the whole submain on a nuisance ground fault. The 300 mA threshold is typical for fire protection or circuits where a lower mA trip would cause unwanted coordination issues. 63 A at 40 °C is the headline number, but the derating curve matters more in a warm enclosure: at 50 °C it's 56.7 A, at 60 °C it's 53.55 A, and at 70 °C it drops to 50.4 A. The 300 mA trip is fixed, non-adjustable, so it's not for variable leakage applications. Type A means it catches pulsating DC residual currents from single-phase rectifiers, which covers most VFD and switched-mode supply scenarios. Snap-on DIN rail mount, 3 modular width units wide. The 77 mm depth and 124 mm width fit standard distribution board cutouts. Supply can land top or bottom, which helps when you're reworking an existing panel and the busbar arrangement is fixed. IP20 with the distribution board installed and conductors connected — fine inside a closed cabinet, not for wet environments. The selective design means it's intended as the upstream RCD in a coordinated system; it won't trip on transient leakage from downstream devices starting up.","metaTitle":"Siemens SENTRON 5SM2645-8 Selective RCD, 4-pole, 63 A, 300 m","metaDescription":"Siemens SENTRON 5SM2645-8 selective RCD unit, 4-pole, 63 A rated, 300 mA Type A, IP20. Current production. Quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Residual Current Breakers (RCCB/RCBO)"],"specifications":{"Depth":"77 mm","Width":"124 mm","title":"5SM2645-8","Height":"90 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"No","description":"RC unit for 5SY, 4-pole, type A, 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":"A","at 40 °C rated value":"58.6 A","at 45 °C rated value":"58.59 A","at 50 °C rated value":"56.7 A","at 55 °C rated value":"54.81 A","at 60 °C rated value":"53.55 A","at 65 °C rated value":"52.29 A","at 70 °C rated value":"50.4 A","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 Current Resistance Rated Value":"5 kA","Surge Voltage Resistance Rated Value":"4 000 V","Value Range Of The Operating Frequency":"50/60 Hz","reference code according to IEC 81346-2":"F","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/f8f2f9d0177b9d090b0f6619e231f764.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=256321&mlfb=5SM2645-8"},"ai":{"faq":[{"question":"What is the closest functional second-source for 5SM2645-8?","answer":"The 5SL4363-7 is a standard (non-selective) 4-pole RCD in the same SENTRON family. The 5SM2645-8 is the selective version with intentional time delay for discrimination. If your design calls for selective coordination, the 5SM is the correct choice; swapping to a 5SL would change the trip coordination profile."},{"question":"Will 5SM2645-8 drop into a panel specified around 5SL4363-7 without rewiring?","answer":"Mechanically yes — same DIN-rail footprint, 3 modular units wide, same 77 mm depth. But the trip coordination changes: the 5SM is selective (delayed), the 5SL is instantaneous. If the panel was designed with selective coordination in mind, swapping to a non-selective unit could cause nuisance tripping on the upstream device."},{"question":"How do I get current pricing and availability for 5SM2645-8?","answer":"This part is sourced and quoted to order through independent distribution. Submit an RFQ for current pricing and availability — confirmed at quote time, not from a static listing."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SM2645-8","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/5SM2645-8 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}}