{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SJ3120-7RC","brand":"Siemens","brandSlug":"siemens","productSlug":"5SJ3120-7RC","canonicalUrl":"https://aoctrl.com/siemens/5SJ3120-7RC","factsUrl":"https://aoctrl.com/api/mcp/products/5SJ3120-7RC","rawCanonicalId":null},"summary":{"shortDescription":"Siemens 5SJ3 Retail line, 1-pole miniature circuit breaker, 20 A rated current, C characteristic, 4.5 kA breaking capacity, order code 5SJ3120-7RC.","salesMarkdown":"The Siemens 5SJ3120-7RC is a 1-pole miniature circuit breaker from the 5SJ3 Retail line, rated 20 A with a C characteristic and 4.5 kA breaking capacity. The C-curve trips between 5× and 10× rated current, making it the standard choice for general-purpose loads like lighting circuits, small motor feeders, and control transformers where moderate inrush is expected. The 4.5 kA breaking capacity covers most residential and light commercial panelboards — check the prospective fault current at the installation point if feeding from a larger transformer. Snap-mounts onto standard 35 mm DIN rail per EN 60715. The 1-pole width (1 module at 17.5 mm) fits tightly in a crowded panel — watch the thermal derating when packing multiple breakers side-by-side at rated load; the manufacturer's derating curve should be applied above three adjacent loaded units. Terminals accept up to 25 mm² conductor for the load side.","metaTitle":"Siemens 5SJ3120-7RC MCB, 1P 20A C-Curve 4.5kA","metaDescription":"Siemens 5SJ3120-7RC MCB, 1-pole 20A C-characteristic 4.5kA breaking capacity. Current lifecycle stage. Sourced 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":"5SJ3120-7RC","description":"MCB Retail line 1p 4.5kA 20A C Characteristic","lifecycle_stage":"current"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/5a10248a3adb61f44f0a697de6ad3a84.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=1477851&mlfb=5SJ3120-7RC"},"ai":{"faq":[{"question":"What does the C characteristic mean on this MCB?","answer":"The C characteristic means the magnetic trip threshold is 5× to 10× rated current (100 A to 200 A for this 20 A breaker). That suits loads with moderate inrush such as small motors, transformers, and lighting banks."},{"question":"Where can I buy the 5SJ3120-7RC?","answer":"The 5SJ3120-7RC is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SJ3120-7RC","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/5SJ3120-7RC 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}}