{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RV2321-4AC20","brand":"Siemens","brandSlug":"siemens","productSlug":"3RV2321-4AC20","canonicalUrl":"https://aoctrl.com/siemens/3RV2321-4AC20","factsUrl":"https://aoctrl.com/api/mcp/products/3RV2321-4AC20","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS circuit breaker, 3RV2321-4AC20, for starter combinations, 55 kA breaking capacity at 400 V AC, spring-loaded terminals, 45 mm width, screw and snap-on DIN rail mounting.","salesMarkdown":"Rated voltage range is 20 to 690 V, covering most common industrial supply levels from control transformers up to 690 V line. At 240 V AC the rating rises to 100 kA, and at 690 V AC it drops to 2 kA — the voltage derating curve is steep, so if your line runs at 690 V, verify the available fault current stays under 2 kA or add a current-limiting upstream fuse. The breaker also carries fuse backup ratings: gL/gG 63 A at 400 V, 50 A at 500 V, and 40 A at 690 V — these are the maximum upstream fuse ratings that preserve the breaker's interrupting capability in a coordinated pair. ## Motor ratings and operating cycle Motor full-load current equivalents: 10 hp at 460/480 V, 5 hp at 220/230 V, 3 hp at 200/208 V, 2 hp at 230 V, and 1 hp at 110/120 V — these are the NEMA horsepower ratings the breaker protects in typical North American motor circuits. Maximum switching rate under AC-3 (motor starting) duty is 15 operations per hour — adequate for a pump or fan that cycles a few times an hour, but not for a high-speed indexing application. Clearance requirements: 50 mm upwards and downwards, 30 mm to the side, 0 mm forwards and backwards — the zero forward/backward clearance means it can sit flush against the back panel or a busbar shield, but the 50 mm vertical gap is mandatory for arc-chamber venting and terminal access.","metaTitle":"Siemens 3RV2321-4AC20 SIRIUS Circuit Breaker, 55 kA at 400 V","metaDescription":"Siemens 3RV2321-4AC20 SIRIUS circuit breaker for starter combinations. 55 kA breaking capacity at 400 V AC, spring-loaded terminals, DIN rail mount. Current lifecycle stage. Quoted","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","title":"3RV2321-4AC20","Height":"119 mm","Upwards":"50 mm","Forwards":"0 mm","at 400 V":"gL/gG 63 A","at 500 V":"gL/gG 50 A","at 690 V":"gL/gG 40 A","Backwards":"0 mm","Downwards":"50 mm","At The Side":"30 mm","Rated Value":"20 ... 690 V","description":"Circuit breaker size S0 for starter combination rated current 16 A N-release 208 A Spring-type terminal Standard switching capacity","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":"2 hp","at 240 V rated value":"100 kA","at 400 V rated value":"25 kA","at 480 V rated value":"16 A","at 500 V rated value":"5 kA","at 600 V rated value":"16 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":"1 hp","at 200/208 V rated value":"3 hp","at 220/230 V rated value":"5 hp","at 460/480 V rated value":"10 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":"9.25 W","at AC-3 at 400 V rated value":"16 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":"16 A","Operating Frequency Rated Value":"50 ... 60 Hz","Operational Current Rated Value":"16 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":"3.1 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":"208 A","insulation voltage with degree of pollution 3 at AC rated value":"690 V"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$36.83","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/2c204ff01372a7df32bcd4f5f4e00693.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=514067&mlfb=3RV2321-4AC20"},"ai":{"faq":[{"question":"What clearance does this breaker need in the panel?","answer":"50 mm above and below, 30 mm to the sides, and zero forwards or backwards — it can mount flush against the back panel."},{"question":"Will 3RV2321-4AC20 drop into a panel specified for 3RV2021-4CA25?","answer":"Both are SIRIUS circuit breakers on the same 45 mm DIN-rail footprint with spring-loaded terminals, so the mechanical fit and wiring are the same — verify the breaking capacity and motor rating match your fault-current study, as the 3RV2321 series carries higher interrupting ratings."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RV2321-4AC20","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/3RV2321-4AC20 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}}