{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SY8420-8","brand":"Siemens","brandSlug":"siemens","productSlug":"5SY8420-8","canonicalUrl":"https://aoctrl.com/siemens/5SY8420-8","factsUrl":"https://aoctrl.com/api/mcp/products/5SY8420-8","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SY8420-8 miniature circuit breaker, 4-pole D-curve, 20 A rated, 30 kA breaking capacity per IEC 60947-2 at 400 V AC, 4-module width.","salesMarkdown":"## Siemens 5SY8420-8 — D-curve 4-pole MCB for high-inrush loads The Siemens 5SY8420-8 is a 4-pole (4P) miniature circuit breaker from the SENTRON series, with a D tripping characteristic rated at 20 A and a 30 kA breaking capacity per IEC 60947-2 at 400 V AC. At 400 V AC the unit delivers its full 30 kA SCCR; under DC per IEC 60947-2 it interrupts 15 kA, and under UL 1077 / CSA C22.2 No. 235 it is rated 5 kA. That 30 kA figure gives real headroom for high-fault panels without cascading upstream breakers. Rated current is temperature-dependent: 20 A at 45 °C, 19.5 A at 50 °C, 18.98 A at 55 °C — so in a warm enclosure you need to account for the derating. Physical footprint: 72 mm wide (4 modular width units), 90 mm tall, 76 mm deep (70 mm installation depth). Mounts in any position on the quick-assembly system (DIN rail).","metaTitle":"Siemens 5SY8420-8 SENTRON MCB, D-curve 4P 20A 30kA IEC","metaDescription":"Siemens 5SY8420-8 SENTRON miniature circuit breaker, 4-pole, D-curve, 20 A, 30 kA breaking capacity per IEC 60947-2. Sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["4-Pole MCB (DIN Rail)"],"specifications":{"Depth":"76 mm","Width":"72 mm","title":"5SY8420-8","Height":"90 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"Yes","description":"Miniature circuit breaker 400 V D=70 mm 25 kA according to EN 60947-2, 4P, D20","Halogen-Free":"Yes","Silicon-Free":"Yes","Number Of Poles":"4","Type Of Voltage":"AC","lifecycle_stage":"current","Fastening Method":"Quick assembly system","Mounting Position":"any","Installation Depth":"70 mm","Product Brand Name":"SENTRON","Degree Of Pollution":"3","Product Designation":"Miniature circuit breaker","acc. to IEC 81346-2":"F","at AC / rated value":"400 V","protection class IP":"IP20, with connected conductors","Overvoltage Category":"III","Combined Terminal Top":"Yes","Number Of Poles / Note":"4P","acc. to DIN EN 61346-2":"F","at 45 °C / rated value":"20 A","at 50 °C / rated value":"19.5 A","at 55 °C / rated value":"18.98 A","Combined Terminal Bottom":"Yes","Suitability For Operation":"Mechanical engineering / industry","Number Of Modular Width Units":"4","Tripping Characteristic Class":"D","Position / Of Power Supply Cord":"Any","acc. to IEC 60947-2 / rated value":"30 kA","Product Feature / Touch Protection":"Yes","Supply Voltage Frequency / Rated Value":"50/60 Hz","Influence Of The Surrounding Temperature":"max. 95% to 55°C, max. 55% to 70°C, max. 35% to 75°C","at DC / acc. to IEC 60947-2 / rated value":"15 kA","at AC / acc. to UL 1077 and CSA C22.2 No.235":"5 kA","vibration resistance / acc. to IEC 60068-2-6":"±1mm at 5 to 25Hz; 50m/s² at 25 to 150Hz","Product Function / Neutral Conductor Switching":"No","with multi-phase operation / at AC / rated value":"440 V","operating voltage / at DC / rated value / maximum":"72 V","with single-phase operation / at AC / rated value":"440 V","Mechanical Service Life (Operating Cycles) / Typical":"10 000"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/7598ee50c66d7d34fc8551dcb8a554c1.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=526059&mlfb=5SY8420-8"},"ai":{"faq":[{"question":"Where can I buy 5SY8420-8 and how do I get a price?","answer":"The 5SY8420-8 is sourced and quoted to order against an RFQ through independent distribution. Current pricing and availability are confirmed at quote time."},{"question":"Will 5SY8420-8 drop into a panel that was specified around 5SY6602-8 without rewiring?","answer":"Both are 4-pole D-curve MCBs on the same 4-module DIN-rail footprint, so the mechanical fit is identical. The 5SY8420-8 carries a higher 30 kA breaking capacity per IEC 60947-2 versus the 5SY6602-8's rating — verify that the downstream fault level does not exceed the lower-rated breaker's capability before swapping."},{"question":"What compliance documentation does this brand provide for 5SY8420-8 (RoHS, REACH, UL, IEC)?","answer":"Siemens provides RoHS, REACH, UL, and IEC compliance documentation with the 5SY8420-8. The unit is rated per IEC 60947-2 (30 kA at 400 V AC) and UL 1077 / CSA C22.2 No. 235 (5 kA)."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SY8420-8","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/5SY8420-8 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}}