{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SM3745-6","brand":"Siemens","brandSlug":"siemens","productSlug":"5SM3745-6","canonicalUrl":"https://aoctrl.com/siemens/5SM3745-6","factsUrl":"https://aoctrl.com/api/mcp/products/5SM3745-6","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON RCCB, 4-pole, 125 A, 500 mA trip, Type A, 10 kA SCCR, 400 V AC, 50 Hz, DIN rail mount, IP20.","salesMarkdown":"## Siemens 5SM3745-6 SENTRON RCCB — 4-pole, 125 A, Type A, instantaneous The Siemens 5SM3745-6 is a 4-pole SENTRON residual current circuit breaker (RCCB) rated for 125 A at 400 V AC, 50 Hz. Full 125 A rating holds up to 45 °C ambient. Above that, derate linearly: 120 A at 50 °C, 115 A at 55 °C, 110 A at 60 °C, 105 A at 65 °C, 100 A at 70 °C. If the panel ambient runs near 50 °C, the 125 A frame still carries 120 A continuous — no need to oversize for a warm cabinet unless you exceed 70 °C. ## Fault current withstand and selectivity Short-circuit current rating (SCCR) is 10 kA per IEC 61008-1, with a let-through current of 8 000 A and a permissible I²t of 94 000 A²·s. For coordination with an upstream MCB, the conditional rating per EN 60898 is 1.25 kA — this is the value to use when the RCCB is backed by a 10 kA MCB in a standard final-distribution board. Surge-current resistance is 1 kA (8/20 µs), so it holds against lightning-induced transients without nuisance tripping.","metaTitle":"Siemens 5SM3745-6 SENTRON RCCB, 4P, 125 A, 500 mA, Type A","metaDescription":"Siemens 5SM3745-6 SENTRON RCCB, 4-pole, 125 A rated, 500 mA trip, Type A, 10 kA SCCR, 400 V AC, 50 Hz. DIN rail mount, IP20. Current production. Quoted to order.","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","at AC rated value":"125 A","Installation Depth":"70 mm","Product Brand Name":"SENTRON","Maximum Permissible":"75 °C","Minimum Permissible":"-40 °C","Product Designation":"RCCB","protection class IP":"IP20, if the distribution board is installed, with connected conductors","Overvoltage Category":"III","Design Of The Product":"Instantaneous","I2t value permissible":"94 000 A²·s","Residual Current Type":"A","at 40 °C rated value":"125 A","at 45 °C rated value":"125 A","at 50 °C rated value":"120 A","at 55 °C rated value":"115 A","at 60 °C rated value":"110 A","at 65 °C rated value":"105 A","at 70 °C rated value":"100 A","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","Let-Through Current Permissible":"8 000 A","according to EN 60898 rated value":"1.25 kA","Tripping Fault Current Rated Value":"500 mA","Surge Current Resistance Rated Value":"1 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","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":"$707.39","priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=197141&mlfb=5SM3745-6","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SM3745-6/alternatives.json"},"ai":{"faq":[{"question":"What are the key ratings of the 5SM3745-6?","answer":"4-pole RCCB, 125 A rated current at 400 V AC, 50 Hz, 500 mA residual trip current, Type A (sinusoidal + pulsating DC detection), instantaneous switching, 10 kA SCCR per IEC 61008-1, DIN rail mount, IP20."},{"question":"What is the depth of the 5SM3745-6?","answer":"77 mm body depth, with an installation depth of 70 mm behind the panel face."},{"question":"What is the width of the 5SM3745-6?","answer":"72 mm, which corresponds to 4 modular-width units on a standard DIN-rail profile."},{"question":"Where can I buy the 5SM3745-6 and get current pricing?","answer":"Sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm commercial offer."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SM3745-6","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/5SM3745-6 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}}