{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SM9420-0KK","brand":"Siemens","brandSlug":"siemens","productSlug":"5SM9420-0KK","canonicalUrl":"https://aoctrl.com/siemens/5SM9420-0KK","factsUrl":"https://aoctrl.com/api/mcp/products/5SM9420-0KK","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON RC unit electronic, 2-pole, type AC, In: 25 A, 100 mA, Un AC: 400 V, 50 Hz, instantaneous design.","salesMarkdown":"The Siemens SENTRON 5SM9420-0KK is a 2-pole residual current unit (RC unit) rated for 25 A operational current at 230/400 V AC, 50 Hz. The type AC designation suits it for general-purpose circuits where the load is purely resistive or inductive with no rectified components. The 25 A rating holds at 40 °C and 45 °C (23.25 A each), then steps down through the temperature range: 22.5 A at 50 °C, 21.75 A at 55 °C, 21.25 A at 60 °C, 20.75 A at 65 °C, and 20 A at 70 °C. If the RC unit sits in a warm enclosure — common in a crowded DIN-rail panel — use the 50 °C or 60 °C column to size the load, not the 25 A headline. ## Panel integration The instantaneous design means it coordinates with upstream overcurrent devices but does not provide selectivity against transient leakage — use a time-delayed (S-type) RC unit if you need coordination with downstream RCDs.","metaTitle":"Siemens SENTRON 5SM9420-0KK RC Unit, 2-Pole, 25 A, 100 mA, T","metaDescription":"Siemens SENTRON 5SM9420-0KK RC unit electronic, 2-pole, type AC, 25 A, 100 mA, 230/400 V AC, 50 Hz. 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":{"Number Of Poles":"2","lifecycle_stage":"current","Product Brand Name":"SENTRON","Product Designation":"RC unit electronic","at AC / rated value":"230/400 V","Design Of The Product":"Instantaneous","Residual Current Type":"AC","at 40 °C / rated value":"23.25 A","at 45 °C / rated value":"23.25 A","at 50 °C / rated value":"22.5 A","at 55 °C / rated value":"21.75 A","at 60 °C / rated value":"21.25 A","at 65 °C / rated value":"20.75 A","at 70 °C / rated value":"20 A","Tripping Fault Current / Rated Value":"100 mA","Supply Voltage Frequency / Rated Value":"50 Hz","operational current / at AC / rated value":"25 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/ba5952acb52586f528d655dc789061f4.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=629198&mlfb=5SM9420-0KK","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SM9420-0KK/alternatives.json"},"ai":{"faq":[{"question":"What are the key ratings for 5SM9420-0KK?","answer":"2-pole, 25 A operational current at 230/400 V AC, 50 Hz, 100 mA residual tripping current, type AC, instantaneous design."},{"question":"Where can I buy 5SM9420-0KK and get current pricing?","answer":"The part is sourced to order against an RFQ through independent distribution. Submit a request for quote to confirm availability and current pricing."},{"question":"Will 5SM9420-0KK drop into a panel specified around 5SQ2270-2YA04 without rewiring?","answer":"No — the 5SQ2270-2YA04 is a 2-pole miniature circuit breaker (MCB) with a 4 A rating and C-curve, not an RC unit. The 5SM9420-0KK is a residual current device; they serve different protection functions and are not drop-in interchangeable."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SM9420-0KK","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/5SM9420-0KK 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}}