{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SM2842-8","brand":"Siemens","brandSlug":"siemens","productSlug":"5SM2842-8","canonicalUrl":"https://aoctrl.com/siemens/5SM2842-8","factsUrl":"https://aoctrl.com/api/mcp/products/5SM2842-8","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON selective residual current unit, 4-pole, type A, rated current 40 A, rated residual current 1000 mA, Un AC 400 V, for DIN rail mounting.","salesMarkdown":"## Selective 4-pole RCD for 5SY series The Siemens SENTRON 5SM2842-8 is a selective residual current unit (RC unit) designed for use with the 5SY miniature circuit breaker series. It is a 4-pole device rated at 40 A AC with a tripping fault current of 1000 mA, type A, making it suitable for detecting sinusoidal AC and pulsating DC residual currents in TN and TT systems. ## What selective means for coordination The selective design (short-time delayed) allows this RCD to coordinate with downstream devices. Under a fault, the downstream RCD trips first, keeping the 5SM2842-8 closed and maintaining supply to the rest of the installation. This avoids a full-panel blackout when a single branch faults — critical for process continuity in industrial panels. The 5 kA surge current resistance confirms it can handle transient overvoltages without nuisance tripping. Mounts on DIN rail (REG), occupying 4 modular width units. Installation depth is 70 mm, total depth 77 mm.","metaTitle":"Siemens SENTRON 5SM2842-8 RC Unit, 4-Pole Type A Selective 4","metaDescription":"Siemens SENTRON 5SM2842-8 selective residual current unit, 4-pole, type A, 40 A, 1000 mA, 400 V AC. Active production. Quoted to order against RFQ.","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","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 Variations":"for 5SY","Maximum Permissible":"75 °C","Minimum Permissible":"-40 °C","Operating Frequency":"50/60 Hz","Product Designation":"RC unit","at AC / rated value":"40 A","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","Number Of Modular Width Units":"4","Product Feature / Silicon-Free":"Yes","For Testing Equipment / Minimum":"195 V","Position / Of Power Supply Cord":"top or bottom","Insulation Voltage / Rated Value":"460 V","Tripping Fault Current / Rated Value":"1 000 mA","Supply Voltage Frequency / Rated Value":"50 Hz","Surge Current Resistance / Rated Value":"5 kA","Switching Function / Short-Term Delayed":"No","size of installation devices / acc. to DIN 43880":"1","Mechanical Service Life (Switching Cycles) / Typical":"10 000"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/98b2738819c9d1678b5b389660fc60f1.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=7710&mlfb=5SM2842-8","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SM2842-8/alternatives.json"},"ai":{"faq":[{"question":"What does the selective design mean for my panel coordination?","answer":"The selective (short-time delayed) design ensures the downstream RCD trips first during a fault, keeping the 5SM2842-8 closed. This prevents upstream tripping that would shut down the entire distribution board for a single branch fault."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SM2842-8","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/5SM2842-8 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}}