{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY4120-8CV","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY4120-8CV","canonicalUrl":"https://aoctrl.com/siemens/5SY4120-8CV","factsUrl":"https://aoctrl.com/api/mcp/products/5SY4120-8CV","rawCanonicalId":null},"summary":{"shortDescription":"Siemens 5SY4 series MCB, 1-pole D20, Icu=15kA 230/400V, order code 5SY4120-8CV.","salesMarkdown":"The Siemens 5SY4120-8CV is a 1-pole miniature circuit breaker with D20 characteristic, rated for a breaking capacity Icu of 15kA at 230/400V. The D20 curve (20A nominal, D-trip) is built for motor and transformer inrush: it tolerates the short-duration surge without nuisance tripping, then clears fast on a hard short. ## Panel fit & deployment Mounts on standard DIN rail — snaps on and off without tools. The 1-pole width (roughly 18mm per pole) leaves room for adjacent breakers in a multi-pole assembly. Rated for 230/400V AC, so it covers single-phase branch circuits in a 400V three-phase panel as well as line-to-neutral loads at 230V. The D20 curve makes it a natural fit for motor branch circuits, small compressor starters, or any inductive load where the inrush peak exceeds the C-curve tolerance.","metaTitle":"5SY4120-8CV MCB 1P D20 15kA 230/400V","metaDescription":"Siemens 5SY4120-8CV MCB, 1-pole D20 curve, Icu=15kA at 230/400V. Current lifecycle stage. Quoted to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["1-Pole MCB (DIN Rail)"],"specifications":{"title":"5SY4120-8CV","description":"MCB Icu=15KA 230/400V 1P D20","lifecycle_stage":"current"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/9d3248f62e9beda7b1bcfe6330c7b168.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=1531881&mlfb=5SY4120-8CV"},"ai":{"faq":[{"question":"What is the breaking capacity of 5SY4120-8CV?","answer":"The MCB has a rated ultimate breaking capacity Icu of 15kA at 230/400V. That's the maximum fault current it can safely interrupt under standard conditions."},{"question":"Where can I buy the 5SY4120-8CV?","answer":"This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — no stock or price figures are published here."},{"question":"What is the 5SY4120-8CV used for?","answer":"It's a 1-pole D20 miniature circuit breaker for branch-circuit protection, particularly suited to motor loads, transformers, and other inductive equipment where the D-curve inrush tolerance prevents nuisance tripping."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY4120-8CV","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/5SY4120-8CV when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-08-11T15:51:03.652Z","lastPublished":"2026-08-11T15:51:03.652Z","indexable":true}}