{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SM3742-6","brand":"Siemens","brandSlug":"siemens","productSlug":"5SM3742-6","canonicalUrl":"https://aoctrl.com/siemens/5SM3742-6","factsUrl":"https://aoctrl.com/api/mcp/products/5SM3742-6","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SM3 series RCCB, 4-pole, Type A, 25 A at 400 V AC, 50 Hz, DIN rail mount, IP20.","salesMarkdown":"The Siemens 5SM3742-6 is a 4-pole residual current circuit breaker (RCCB) from the SENTRON 5SM3 series, designed for DIN-rail mounting in distribution boards. It protects against earth faults by detecting the imbalance between live and neutral currents — the Type A designation means it catches pulsating DC fault currents as well as sinusoidal AC, which is the standard for modern electronics-fed loads like VFDs, switched-mode power supplies, and LED drivers. Rated 25 A at 400 V AC, 50 Hz, with a short-circuit current rating of 10 kA, this unit handles the typical residential and light commercial supply. The 4-pole construction (3 phases + neutral) suits three-phase panelboards where all live conductors must be disconnected on a fault. ## Thermal derating and conductor sizing The 25 A rating holds up to 45 °C ambient; above that it derates linearly to 20 A at 70 °C. If your panel runs hot — near a transformer or in a non-ventilated enclosure — check the derating curve: at 55 °C you're down to 23 A, at 65 °C to 21 A. The terminal range accepts 1.5 to 25 mm² solid or stranded copper, which covers the full range of conductors for a 25 A circuit. Occupies 4 width units (72 mm) on a DIN rail, with a depth of 77 mm and an installation depth of 70 mm.","metaTitle":"Siemens 5SM3742-6 SENTRON RCCB, 4-pole, 25 A, 400 V AC, Type","metaDescription":"Siemens 5SM3742-6 SENTRON 4-pole RCCB, 25 A rated at 400 V AC, Type A, 10 kA SCCR. Current lifecycle status. 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","Solid":"1.5 ... 25 mm²","Width":"72 mm","Height":"90 mm","Stranded":"1.5 ... 25 mm²","at 40 Cel":"25 A","at 45 Cel":"25 A","at 50 Cel":"24 A","at 55 Cel":"23 A","at 60 Cel":"22 A","at 65 Cel":"21 A","at 70 Cel":"20 A","Rated Value":"50 Hz","Wertebereich":"-25 ... +45 °C","Mounting type":"DIN rail (REG)","Number of poles":"4","lifecycle_stage":"current","Mounting position":"any","Installation depth":"70 mm","Product brand name":"SENTRON","Ambient temperature":"-40 ... +75 °C","Operating frequency":"50Hz","Product designation":"RCCB","Protection class IP":"IP20, if the distribution board is installed, with connected conductors","Overvoltage category":"III","Design of the product":"Instantaneous","Number of width units":"4","Type of fault current":"A","acc. to DIN EN 61346-2":"F","acc. to DIN EN 81346-2":"F","I2t-value / permissible":"70 000 A²·s","circuit-breaker / Design":"5SM3","Short-circuit current rating":"10 kA","Current / at AC / rated value":"25 A","Product feature / silicon-free":"Yes","Position / of power supply cord":"top or bottom","Protection against electrical shock":"Finger and back-of-hand safe","Supply voltage / at AC / rated value":"400 V","Surge current resistance / rated value":"1 kA","Switching function / short-term delayed":"No","Tripping residual current / rated value":"500 mA","Tightening torque / with screw-type terminals":"2.5 ... 3 N·m","Size of installation devices / acc. to DIN 43880":"1","Supply voltage / for testing equipment / minimum":"100 V","Mechanical service life (switching cycles) / typical":"10 000"}},"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=214951&mlfb=5SM3742-6","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SM3742-6/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy 5SM3742-6 and get a price?","answer":"This part is sourced to order against an RFQ through independent distribution channels. Submit an RFQ for current availability and pricing."},{"question":"What is the depth of 5SM3742-6?","answer":"The depth is 77 mm, with an installation depth of 70 mm on the DIN rail."},{"question":"What conductor sizes does 5SM3742-6 accept?","answer":"Terminals accept 1.5 to 25 mm² solid or stranded copper conductors."},{"question":"What compliance documentation is available for 5SM3742-6?","answer":"The product carries IP20 protection class (installed), overvoltage category III, and is designed to DIN EN 61346-2 and DIN EN 81346-2 standards. It is silicon-free. Specific RoHS/REACH/UL declarations should be confirmed at quote time."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SM3742-6","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/5SM3742-6 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}}