{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RV6321-4NC10","brand":"Siemens","brandSlug":"siemens","productSlug":"3RV6321-4NC10","canonicalUrl":"https://aoctrl.com/siemens/3RV6321-4NC10","factsUrl":"https://aoctrl.com/api/mcp/products/3RV6321-4NC10","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS circuit breaker, for starter combinations, size S0, 3-pole, 28 A AC-3 at 400 V, 690 V rated, magnetic short-circuit trip 400 A, screw terminals, snap-on DIN rail.","salesMarkdown":"The Siemens 3RV6321-4NC10 is a SIRIUS circuit breaker specifically designed for starter combinations — meaning it combines motor protection (overload and short-circuit) in a single device sized to coordinate with a contactor downstream. It's a 3-pole, size S0 frame breaker rated 28 A in AC-3 duty at 400 V, so it switches motor loads up to that current under the standard motor-switching category (AC-3 covers starting and plugging of squirrel-cage motors). The magnetic short-circuit trip responds at 400 A, which is the instantaneous threshold; below that, the thermal bimetal handles overloads. The 45 mm width (one S0 module) keeps panel density reasonable. Fastening torque for the main screw terminals is 2 to 2.5 N·m. Wire range: accepts 2x (1 to 2.5 mm²) solid or stranded, or 2x (2.5 to 10 mm²) — also 2x (16 to 12) and 2x (14 to 8) AWG. Finely stranded with ferrule: 2x (1 to 2.5 mm²), 2x (2.5 to 6 mm²), or 1x 10 mm². Connectors are top and bottom entry. Mounting position is any, but clearance distances must be observed: 50 mm upwards and downwards, 30 mm at the sides, 0 mm forwards and backwards — this matters for heat dissipation and arc flash clearance in a packed enclosure. ## Ratings and operating conditions Rated operational current is 28 A at AC-3, 400 V. Operating frequency at AC-3: maximum 15 operations per hour — that's a thermal limit, not a switching-speed spec; don't cycle a motor faster than this without checking the contactor and load duty. Ambient temperature during operation: -20 to +60 °C. Storage/transport: -50 to +80 °C. Relative humidity: 10 to 95%. Installation altitude maximum: 2000 m. Shock resistance: 25 g / 11 ms per IEC 60068-2-27. The 690 V rated value and 6 kV surge resistance confirm it's suitable for 400 V systems with good margin, but verify coordination with upstream protection. Substance prohibitance date (RoHS) is 05/01/2012 — the part complies with RoHS as of that date. The SIRIUS range typically carries UL, CSA, and CE certifications; the insulation voltage rating of 690 V at pollution degree 3 is a key parameter for IEC 60947-2 compliance. For UL 508A panel builders, verify the SCCR coordination with the downstream contactor — the 400 A magnetic trip sets the let-through energy for the combination.","metaTitle":"Siemens 3RV6321-4NC10 SIRIUS Circuit Breaker, 28 A AC-3, 690","metaDescription":"Siemens 3RV6321-4NC10 SIRIUS circuit breaker for starter combinations. 28 A AC-3 at 400 V, 690 V rated, size S0, magnetic trip 400 A. Current lifecycle stage. Sourced to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Motor Protection Circuit Breakers (MPCB)"],"specifications":{"Depth":"96 mm","Width":"45 mm","Height":"97 mm","Upwards":"50 mm","Forwards":"0 mm","Backwards":"0 mm","Downwards":"50 mm","At The Side":"30 mm","Rated Value":"690 V","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 60715","Mounting Position":"any","Solid Or Stranded":"2x (1 ... 2.5 mm²), 2x (2.5 ... 10 mm²)","Product Brand Name":"SIRIUS","Product Designation":"Circuit breaker","Design Of The Product":"for starter combinations","For Main Current Circuit":"screw-type terminals","Size Of The Circuit-Breaker":"S0","at AC-3 rated value maximum":"690 V","power loss [W] total typical":"11 W","Substance Prohibitance (Date)":"05/01/2012","Operating Frequency Rated Value":"50 ... 60 Hz","Operational Current Rated Value":"28 A","at AWG cables for main contacts":"2x (16 ... 12), 2x (14 ... 8)","Design Of The Short-Circuit Trip":"magnetic","Relative Humidity During Operation":"10 ... 95 %","operating frequency at AC-3 maximum":"15 1/h","Surge Voltage Resistance Rated Value":"6 kV","Finely Stranded With Core End Processing":"2x (1 ... 2.5 mm²), 2x (2.5 ... 6 mm²), 1x 10 mm²","Number Of Poles For Main Current Circuit":"3","Product Function Short Circuit Protection":"Yes","For Main Contacts With Screw-Type Terminals":"2 ... 2.5 N·m","shock resistance according to IEC 60068-2-27":"25g / 11 ms","operational current at AC-3 at 400 V rated value":"28 A","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Arrangement Of Electrical Connectors For Main Current Circuit":"Top and bottom","Response Value Current Of Instantaneous Short-Circuit Trip Unit":"400 A","insulation voltage with degree of pollution 3 at AC rated value":"690 V","breaking capacity maximum short-circuit current (Icu) at AC at 400 V rated value":"55 kA","breaking capacity operating short-circuit current (Ics) at AC at 400 V rated value":"25 kA"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/d5051398b4ac7073b92ad41313260956.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=621319&mlfb=3RV6321-4NC10","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RV6321-4NC10/alternatives.json"},"ai":{"faq":[{"question":"What is the closest functional alternative to 3RV6321-4NC10?","answer":"The 3RV6021-4DA10 is a similar SIRIUS size S0 circuit breaker for starter combinations, but it has a different trip rating and magnetic setting. Verify your motor FLA and short-circuit requirements before substituting; the 3RV6321-4NC10 carries a 28 A AC-3 rating at 400 V with a 400 A instantaneous magnetic trip, so the peer may differ on those values."},{"question":"What compliance documentation does 3RV6321-4NC10 have?","answer":"RoHS compliance dated 05/01/2012. The SIRIUS series typically carries UL, CSA, and CE certifications for industrial control equipment. The insulation voltage is rated 690 V at pollution degree 3 per IEC 60947-2."},{"question":"Where can I buy 3RV6321-4NC10 and how is it quoted?","answer":"This part is sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm price and lead time."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RV6321-4NC10","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/3RV6321-4NC10 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}}