{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SJ6120-7","brand":"Siemens","brandSlug":"siemens","productSlug":"5SJ6120-7","canonicalUrl":"https://aoctrl.com/siemens/5SJ6120-7","factsUrl":"https://aoctrl.com/api/mcp/products/5SJ6120-7","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SJ6 series, miniature circuit breaker, 1-pole, C-curve, 20 A rated at 240 V AC, 6 kA breaking capacity, 70 mm installation depth.","salesMarkdown":"The Siemens SENTRON 5SJ6120-7 is a 1-pole miniature circuit breaker (MCB) from the 5SJ6 series, rated 20 A at 240 V AC with a C tripping characteristic. The 6 kA breaking capacity (rated per EN 60898 and IEC 60947-2) tells you it can safely interrupt a fault current up to 6 kA at the rated voltage; that's sufficient for most sub-distribution boards fed by a transformer of typical impedance, but if your available fault current exceeds 6 kA at the panel, you'll need to coordinate upstream or step to a higher-rated MCB. It occupies a single width unit (1 PU) on the DIN rail — 17.8 mm — so it fits tight enclosures where every slot counts. The 70 mm installation depth is standard for the 5SJ6 family, meaning it clears most 100 mm deep distribution boxes without issue. ## Temperature range and environmental limits Storage temperature spans -40 to +75 °C — that's the range for warehousing and transport, not operation. The operating ambient is -20 to +45 °C (the standard for this class), with periodic excursions to +55 °C at up to 95% humidity. If you're mounting this breaker in a non-air-conditioned enclosure near a furnace or in a Middle Eastern plant, the 45 °C ceiling is the number to watch: above that, you need to derate the 20 A rating or provide ventilation. The 75 °C max is strictly a non-operating limit for shelf life. ## Voltage ratings and multi-phase use That means a 1-pole breaker like this can be ganged with others on a 3-phase 400 V system (line-to-neutral on a 230/400 V supply), but each pole only switches its own phase. For DC circuits, the maximum rated voltage is 60 V — so it works on 24 V or 48 V DC control buses, but not on a 110 V DC battery bank. ## Mechanical life and vibration resistance Rated for 20,000 mechanical switching cycles — that's typical for an MCB in distribution duty where it's operated maybe a few times a year for isolation. If you're using it as a daily disconnect on a machine, the cycle count is fine for years of service. Vibration resistance is 50 m/s² at 25 to 150 Hz and 60 m/s² at 10 to 150 Hz per IEC 60068-2-6, which covers most industrial panel vibration from contactors and drives mounted on the same rail. The closest functional sibling is the 5SJ6220-6 — same 20 A rating, same 6 kA breaking capacity, same 5SJ6 family, but 2-pole and B-curve instead of C-curve. The 2-pole version takes two width units on the DIN rail (35.6 mm) versus one for the 1-pole 5SJ6120-7. If your panel was wired for a 2-pole B-curve breaker, the 1-pole C-curve won't drop in without rewiring the neutral and checking the trip coordination. For a 1-pole 20 A C-curve application, the 5SJ6120-7 is the direct fit.","metaTitle":"Siemens 5SJ6120-7 SENTRON MCB, 1-Pole C 20A 6kA 240V","metaDescription":"Siemens SENTRON 5SJ6120-7 miniature circuit breaker, 1-pole, C-curve, 20A, 6kA breaking capacity per EN 60898 / IEC 60947-2. Current production. Quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["1-Pole MCB (DIN Rail)"],"specifications":{"Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","Rated Value":"50 Hz","Halogen-Free":"Yes","Silicon-Free":"Yes","Number of poles":"1","Type of voltage":"AC/DC","lifecycle_stage":"current","Mounting position":"any","Installation depth":"70 mm","Product brand name":"SENTRON","Degree of pollution":"2","Product designation":"Miniature circuit breakers","Protection class IP":"IP20, with connected conductors","Overvoltage category":"3","Design of the product":"Miniature circuit breaker 5SJ6","Energy limiting class":"3","Number of width units":"1","Number of poles / Note":"1","circuit-breaker / Design":"5SJ6","Tripping characteristic class":"C","at DC / rated value / maximum":"60 V","acc. to EN 60898 / rated value":"6 kA","Position / of power supply cord":"Any","acc. to IEC 60947-2 / rated value":"6 kA","Product feature / Touch protection":"Yes","Supply voltage / at AC / rated value":"240 V","Operating current / at AC / rated value":"20 A","Influence of the surrounding temperature":"Periodically +55°C, max. 95% humidity","Insulation voltage / at AC / rated value":"440 V","Vibration resistance / acc. to IEC 60068-2-6":"50m/s² at 25 to 150Hz and 60m/s² at 10 to 150 Hz","with multi-phase operation / at AC / maximum":"440 V","Mechanical service life (switching cycles) / typical":"20 000"}},"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=177966&mlfb=5SJ6120-7","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SJ6120-7/alternatives.json"},"ai":{"faq":[{"question":"What is the 5SJ6120-7's maximum and minimum temperature range?","answer":"Storage range is -40 to +75 °C; operating ambient is -20 to +45 °C with periodic excursions to +55 °C at up to 95% humidity. The 75 °C maximum is a non-operating storage limit."},{"question":"Will the 5SJ6120-7 replace a 5SJ6220-6 without rewiring?","answer":"No — the 5SJ6220-6 is a 2-pole B-curve breaker; the 5SJ6120-7 is 1-pole C-curve. They differ in pole count, tripping characteristic, and DIN rail width (1 PU vs 2 PU). Rewiring and coordination review are required."},{"question":"Where can I buy the 5SJ6120-7 and get current pricing?","answer":"This part is sourced and quoted to order against an RFQ through our independent distribution network. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm commercial offer."},{"question":"What compliance documentation does Siemens provide for the 5SJ6120-7?","answer":"As a standard SENTRON MCB, it carries CE marking for the European market and is designed to EN 60898 and IEC 60947-2. The part is halogen-free and silicon-free. RoHS and REACH declarations are typically available from Siemens documentation portals."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SJ6120-7","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/5SJ6120-7 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}}