{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SM3745-0","brand":"Siemens","brandSlug":"siemens","productSlug":"5SM3745-0","canonicalUrl":"https://aoctrl.com/siemens/5SM3745-0","factsUrl":"https://aoctrl.com/api/mcp/products/5SM3745-0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON RCCB, 4-pole, type AC, In: 125 A, 500 mA, Un AC: 400 V, 10 kA SCCR, DIN rail mount, 4 MW.","salesMarkdown":"The Siemens 5SM3745-0 is a 4-pole residual current circuit breaker (RCCB) from the SENTRON family, rated 125 A with a 500 mA trip sensitivity at 400 V AC, 50 Hz. It's an instantaneous (type AC) device — no intentional delay, so it trips on sinusoidal AC fault currents as soon as they exceed the threshold. Snaps onto DIN rail (REG profile), 4 modular width units wide (72 mm). Mounting position is unrestricted — horizontal, vertical, upside-down, doesn't matter. Depth is 77 mm, installation depth 70 mm. The IP20 rating applies once the distribution board is installed with conductors connected; it's a panel-internal device, not a standalone outdoor unit. The 500 mA sensitivity is a high-threshold trip — it's for equipment protection or circuits with high natural leakage (long cable runs, industrial heaters), not personnel protection (which typically uses 30 mA). The 125 A rating and 400 V AC make it a main-switch or feeder RCCB for a sub-distribution board.","metaTitle":"Siemens 5SM3745-0 SENTRON RCCB, 125 A, 500 mA, 400 V AC","metaDescription":"Siemens 5SM3745-0 SENTRON 4-pole RCCB, type AC, 125 A rated, 500 mA sensitivity, 400 V AC, 10 kA SCCR. Current lifecycle stage. Available 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","Width":"72 mm","Height":"90 mm","Maximum":"45 °C","Minimum":"-5 °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 Designation":"RCCB","protection class IP":"IP20, if the distribution board is installed, with connected conductors","Overvoltage Category":"III","Design Of The Product":"Instantaneous","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","according to EN 60898 rated value":"1.25 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","Ambient Temperature During Storage Minimum":"-40 °C","Value Range Of The Supply Voltage Frequency":"50 Hz","Supply Voltage For Testing Equipment Minimum":"195 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":null,"priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=222994&mlfb=5SM3745-0","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SM3745-0/alternatives.json"},"ai":{"faq":[{"question":"What is the 5SM3745-0 used for?","answer":"It's a 4-pole residual current circuit breaker (RCCB) for AC circuits up to 400 V, rated 125 A with 500 mA trip sensitivity. It protects against earth faults in industrial or commercial distribution panels."},{"question":"Where can I buy the 5SM3745-0?","answer":"The part is sourced and quoted to order against an RFQ through independent distribution channels. Availability and current pricing are confirmed at quote time."},{"question":"Will the 5SM3745-0 fit in a panel designed for a 5SL4363-7?","answer":"Not without rewiring. The 5SM3745-0 is a 4-pole RCCB at 4 MW wide (72 mm), while the 5SL4363-7 is a 3-pole MCB at 3 MW (54 mm). The 18 mm width difference means the DIN-rail space and the terminal layout don't align."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SM3745-0","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/5SM3745-0 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}}