{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RV1421-4AA38-1KT0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RV1421-4AA38-1KT0","canonicalUrl":"https://aoctrl.com/siemens/3RV1421-4AA38-1KT0","factsUrl":"https://aoctrl.com/api/mcp/products/3RV1421-4AA38-1KT0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RV1421-4AA38-1KT0, circuit breaker for transformer protection, 16 A, Class 10, 50 kA breaking capacity at 400 V AC, screw terminals, IP20 front.","salesMarkdown":"The Siemens SIRIUS 3RV1421-4AA38-1KT0 is a circuit breaker specifically designed for transformer protection — not a general-purpose motor-protective breaker, but one tuned to handle the inrush and thermal characteristics of transformers. The 45 mm width means it takes up a single modular space in a standard panel layout. Rated at 16 A continuous current, this breaker handles transformer loads up to that steady-state value. The Class 10 trip characteristic means it will hold through the high inrush of an energizing transformer (typically 8–12x rated for 0.1–0.5 s) but still trip quickly on a hard fault — critical for protecting both the transformer and downstream wiring. Breaking capacity is the real selector here: 100 kA at 240 V AC, 50 kA at 400 V AC, 10 kA at 500 V AC, and 4 kA at 690 V AC. No ground-fault detection on this variant, so if that's required, you'd need an add-on module or a different base unit. The auxiliary switch is transverse-mounted, and its ratings are 1 A at 24 V, 0.15 A at 60 V, and 0.5 A at 230 V — enough for signaling to a PLC or indicator lamp. ## Mounting and Environment Zero clearance needed at the sides or back — 0 mm spacing — so you can pack modules tight in the enclosure. Shock-rated at 25g for 11 ms — fine for most industrial environments including machine-mounted panels.","metaTitle":"Siemens 3RV1421-4AA38-1KT0 SIRIUS Circuit Breaker, 16 A, Cla","metaDescription":"Siemens 3RV1421-4AA38-1KT0 SIRIUS circuit breaker for transformer protection. 16 A continuous, Class 10 trip, 50 kA at 400 V. Active production, sourced to order. Request a quote.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Motor Protection Circuit Breakers (MPCB)"],"specifications":{"Depth":"96 mm","Solid":"2x (0.25 ... 2.5 mm²)","Width":"45 mm","Height":"97 mm","at 24 V":"1 A","at 60 V":"0.15 A","at 230 V":"0.5 A","Backwards":"0 mm","Trip Class":"CLASS 10","At The Side":"0 mm","Rated Value":"690 V","During Storage":"-50 ... +80 °C","lifecycle_stage":"current","During Operation":"-20 ... +60 °C","During Transport":"-50 ... +80 °C","Fastening Method":"screw and snap-on mounting onto 35 mm standard mounting rail according to DIN EN 50022","Shock Resistance":"25g / 11 ms","Mounting Position":"any","Product Brand Name":"SIRIUS","Product Designation":"circuit breaker","Design Of The Product":"for transformer protection","Ground Fault Detection":"No","Phase Failure Detection":"Yes","For Main Current Circuit":"screw-type terminals","at AC at 240 V rated value":"100 kA","at AC at 400 V rated value":"50 kA","at AC at 500 V rated value":"10 kA","at AC at 690 V rated value":"4 kA","at AC-3 rated value maximum":"690 V","at AC in hot operating state":"9.25 W","Substance Prohibitance (Date)":"01.05.2012","Continuous Current Rated Value":"16 A","Design Of The Auxiliary Switch":"transverse","at AWG cables for main contacts":"2x (24 ... 14)","protection class IP on the front":"IP20","For Auxiliary And Control Circuit":"spring-loaded terminals","Product Extension Auxiliary Switch":"Yes","operating frequency at AC-3 maximum":"15 1/h","Surge Voltage Resistance Rated Value":"6 000 V","at AWG cables for auxiliary contacts":"2x (24 ... 14)","at AC in hot operating state per pole":"3.1 W","Finely Stranded With Core End Processing":"2x (0.25 ... 1.5 mm²)","Number Of Poles For Main Current Circuit":"3","Touch Protection Against Electrical Shock":"finger-safe","Finely Stranded Without Core End Processing":"2x (0.25 ... 2.5 mm²)","number of CO contacts for auxiliary contacts":"0","operational current at AC-3 at 400 V rated value":"16 A","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Design Of The Overcurrent Release And Short-Circuit Release":"thermomagnetic","Arrangement Of Electrical Connectors For Main Current Circuit":"front side","Product Component Removable Terminal For Auxiliary And Control Circuit":"No","Mechanical Service Life (Switching Cycles) Of The Main Contacts Typical":"100 000","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"11 ... 16 A"}},"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=531324&mlfb=3RV1421-4AA38-1KT0","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RV1421-4AA38-1KT0/alternatives.json"},"ai":{"faq":[{"question":"What is the breaking capacity of 3RV1421-4AA38-1KT0 at 400 V?","answer":"50 kA at 400 V AC, which covers most industrial distribution panel fault-current levels without requiring an upstream current-limiting fuse."},{"question":"Where can I buy 3RV1421-4AA38-1KT0 and how is it quoted?","answer":"We source this part to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — just send the RFQ."},{"question":"What compliance documentation is available for this breaker?","answer":"The part is RoHS-compliant with a substance prohibition date of 01.05.2012. Standard Siemens SIRIUS documentation includes CE, UL, and CSA certifications as part of the series listing."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RV1421-4AA38-1KT0","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/3RV1421-4AA38-1KT0 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}}