{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RV2321-4EC20","brand":"Siemens","brandSlug":"siemens","productSlug":"3RV2321-4EC20","canonicalUrl":"https://aoctrl.com/siemens/3RV2321-4EC20","factsUrl":"https://aoctrl.com/api/mcp/products/3RV2321-4EC20","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS circuit breaker for starter combinations, 3RV2321-4EC20, 55 kA at 400 V AC, screw and snap-on 35 mm DIN rail mount, spring-loaded terminals.","salesMarkdown":"The 3RV2321-4EC20: The headline number for this class is the short-circuit breaking capacity. At 400 V AC, this breaker interrupts 55 kA. At 240 V AC it's rated 100 kA, at 500 V it drops to 5 kA, and at 690 V to 2 kA. The SCCR drops as voltage rises — that's normal for this class, but it means a 480 V panel with a 65 kA available fault current needs the 55 kA rating at 400 V, not the 2 kA at 690 V. Motor horsepower ratings are given across common voltages: 5 hp at 230 V, 10 hp at 220/230 V, 20 hp at 460/480 V. That tells you the maximum standard induction motor this breaker can protect at those line voltages. For a 480 V 20 hp pump motor, this breaker is sized right. If you're running a 25 hp compressor at the same voltage, you'd step up the frame. That's the maximum upstream fuse that still lets the breaker's own interrupting rating hold. If your panel feeds this breaker through a 100 A fuse, you lose the coordination and the SCCR drops to the fuse's rating — a common miss during panel build. ## Mounting and wiring in the panel The snap-on feature means no tools for the rail mount — useful when you're swapping this into an existing panel. Mounting position is any orientation, so vertical or horizontal rail is fine. Clearance requirements: 50 mm upward and downward, 30 mm to the side, 0 mm forward and backward. The zero forward/backward clearance means you can butt this against the back panel or a busbar cover without derating — a real space saver in a dense cabinet. Main circuit connection uses spring-loaded terminals — no screwdriver torque spec to chase, just strip and push. For a 20 hp motor at 480 V pulling about 27 A full load, 10 mm² is adequate. The spring clamp means faster terminations and no vibration loosening on a conveyor line. If you're replacing a different brand's 45 mm breaker, the footprint matches. ## Environmental and operational limits Rated operating voltage range is 20 to 690 V — covers everything from 24 V control circuits up to 690 V industrial mains. The -20 °C floor means it's fine in an unheated warehouse in most climates; below that you'd need a space heater in the panel. Maximum switching frequency in AC-3 duty is 15 operations per hour — that's typical for a manual motor starter, not a contactor cycling a weld gun every 10 seconds. No ground fault detection and no phase failure detection built in. That's expected for this class — it's a thermal-magnetic overload and short-circuit protector, not an electronic motor protection relay. If you need phase-loss or ground-fault protection, you add a separate relay or use a SIRIUS 3RB series electronic overload.","metaTitle":"Siemens 3RV2321-4EC20 SIRIUS Circuit Breaker, 55 kA at 400 V","metaDescription":"Siemens 3RV2321-4EC20 SIRIUS circuit breaker for starter combinations. 55 kA SCCR at 400 V AC, screw/DIN rail mount. Current production. Available to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Motor Protection Circuit Breakers (MPCB)"],"specifications":{"Depth":"97 mm","Width":"45 mm","Height":"119 mm","Upwards":"50 mm","Forwards":"0 mm","at 400 V":"gL/gG 63 A","at 500 V":"gL/gG 63 A","at 690 V":"gL/gG 63 A","Backwards":"0 mm","Downwards":"50 mm","At The Side":"30 mm","Rated Value":"20 ... 690 V","During Storage":"-50 ... +80 °C","at AC-3 maximum":"15 1/h","lifecycle_stage":"current","During Operation":"-20 ... +60 °C","During Transport":"-50 ... +80 °C","Fastening Method":"screw and snap-on mounting onto 35 mm DIN rail according to DIN EN 60715","at AC-3e maximum":"15 1/h","Mounting Position":"any","Solid Or Stranded":"2x (1 ... 10 mm²)","Product Brand Name":"SIRIUS","Product Designation":"Circuit breaker","at 230 V rated value":"5 hp","at 240 V rated value":"100 kA","at 400 V rated value":"25 kA","at 480 V rated value":"32 A","at 500 V rated value":"5 kA","at 600 V rated value":"32 A","at 690 V rated value":"2 kA","Design Of The Product":"For starter combinations","Ground Fault Detection":"No","Phase Failure Detection":"No","For Main Current Circuit":"spring-loaded terminals","at 110/120 V rated value":"2 hp","at 200/208 V rated value":"7.5 hp","at 220/230 V rated value":"10 hp","at 460/480 V rated value":"20 hp","at AC at 240 V rated value":"100 kA","at AC at 400 V rated value":"55 kA","at AC at 500 V rated value":"10 kA","at AC at 690 V rated value":"4 kA","Design Of Screwdriver Shaft":"Diameter 3 mm","Size Of The Circuit-Breaker":"S0","Size Of The Screwdriver Tip":"3,0 x 0,5 mm","at AC-3 rated value maximum":"690 V","Of The Main Contacts Typical":"100 000","at AC in hot operating state":"13.25 W","at AC-3 at 400 V rated value":"32 A","at AC-3e rated value maximum":"690 V","Of Auxiliary Contacts Typical":"100 000","Substance Prohibitance (Date)":"10/01/2009","at AC-3e at 400 V rated value":"32 A","Operating Frequency Rated Value":"50 ... 60 Hz","Operational Current Rated Value":"32 A","at AWG cables for main contacts":"2x (18 ... 8)","Design Of The Short-Circuit Trip":"magnetic","Product Extension Auxiliary Switch":"Yes","Relative Humidity During Operation":"10 ... 95 %","Display Version For Switching Status":"Handle","Surge Voltage Resistance Rated Value":"6 kV","at AC in hot operating state per pole":"4.4 W","With Side-By-Side Mounting At The Side":"0 mm","reference code according to IEC 81346-2":"Q","Finely Stranded With Core End Processing":"2x (1 ... 6 mm²)","Number Of Poles For Main Current Circuit":"3","Product Function Short Circuit Protection":"Yes","with low demand rate according to SN 31920":"50 FIT","Finely Stranded Without Core End Processing":"2x (1 ... 6 mm²)","with high demand rate according to SN 31920":"50 %","number of CO contacts for auxiliary contacts":"0","number of NC contacts for auxiliary contacts":"0","number of NO contacts for auxiliary contacts":"0","shock resistance according to IEC 60068-2-27":"25g / 11 ms","Electrical Endurance (Operating Cycles) Typical":"100 000","Size Of Contactor Can Be Combined Company-Specific":"S00, S0","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"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$59.69","priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=188084&mlfb=3RV2321-4EC20","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RV2321-4EC20/alternatives.json"},"ai":{"faq":[{"question":"What is the short-circuit breaking capacity of 3RV2321-4EC20 at 400 V?","answer":"At 400 V AC, the interrupting rating is 55 kA. At 240 V AC it's 100 kA, at 500 V it's 5 kA, and at 690 V it's 2 kA."},{"question":"What motor horsepower can the 3RV2321-4EC20 protect at 480 V?","answer":"At 460/480 V, the breaker is rated for 20 hp. At 230 V it's 5 hp, at 200/208 V it's 7.5 hp."},{"question":"Where can I buy the 3RV2321-4EC20 and how is it quoted?","answer":"This part is sourced to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm commercial offer."},{"question":"Will 3RV2321-4EC20 drop into a panel designed for 3RV2021-4NA25 without rewiring?","answer":"Both are 45 mm wide SIRIUS breakers on 35 mm DIN rail, so the footprint and rail position match. The 3RV2021-4NA25 is a different frame size with different SCCR and trip ratings — verify the interrupting capacity and motor FLA settings match before swapping, but the mechanical fit is the same."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RV2321-4EC20","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/3RV2321-4EC20 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}}