{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RV2121-4CA10","brand":"Siemens","brandSlug":"siemens","productSlug":"3RV2121-4CA10","canonicalUrl":"https://aoctrl.com/siemens/3RV2121-4CA10","factsUrl":"https://aoctrl.com/api/mcp/products/3RV2121-4CA10","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RV2121-4CA10 motor protection circuit breaker with integrated overload relay, Class 10, 25 kA SCCR at 400 V, screw terminals, 97 x 65 x 97 mm.","salesMarkdown":"## Motor protection circuit breaker with overload relay — SIRIUS 3RV2121-4CA10 It combines the two functions into one compact unit, saving panel space and wiring compared to a separate circuit breaker plus thermal overload relay. This is the correct class for general-purpose motor starting; a Class 20 would allow longer acceleration but provides less protection against sustained overload. ## Short-circuit ratings and selectivity planning This breaker carries a short-circuit breaking capacity of 25 kA at 400 V AC, 100 kA at 240 V, 5 kA at 500 V, and 2 kA at 690 V. For most 400 V industrial distribution panels, the 25 kA SCCR provides adequate headroom; if the available fault current exceeds that, you would need to coordinate with an upstream current-limiting fuse or MCCB rated higher. The listed fault-current ratings are for gL/gG fuses in series — at 400 V the maximum fuse rating is 63 A, and at 500 V and 690 V it is 50 A. This coordination data allows the panel designer to select the upstream fuse such that the breaker remains the protective device for downstream motor faults without unwanted fuse blowing. The 65 mm width occupies three standard 18 mm DIN-rail module slots, leaving room for auxiliary contact blocks or a separate contactor alongside. Screw-type terminals on the main circuit accept 2 × (0.5…1.5 mm²) or 2 × (0.75…2.5 mm²) solid or stranded wire. The main contact screws are M4.","metaTitle":"Siemens SIRIUS 3RV2121-4CA10 Motor Protection Circuit Breake","metaDescription":"Siemens SIRIUS 3RV2121-4CA10 motor protection circuit breaker with overload relay, Class 10 trip, 25 kA SCCR at 400 V. Phase failure detection, DIN rail mount, current production.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Motor Protection Circuit Breakers (MPCB)"],"specifications":{"Depth":"97 mm","Width":"65 mm","title":"3RV2121-4CA10","Height":"97 mm","Upwards":"50 mm","at 24 V":"1 A","Forwards":"0 mm","at 230 V":"1.5 A","at 400 V":"gL/gG 63 A","at 500 V":"gL/gG 50 A","at 690 V":"gL/gG 50 A","Backwards":"0 mm","Downwards":"50 mm","Trip Class":"CLASS 10","At The Side":"30 mm","Rated Value":"20 ... 690 V","description":"Circuit breaker size S0 for motor protection, CLASS 10 with overload relay function A-release 16...22 A N-release 286 A screw 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","For Main Contacts":"M4","Mounting Position":"any","Solid Or Stranded":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)","Product Brand Name":"SIRIUS","Product Designation":"Circuit breaker","at 230 V rated value":"3 hp","at 240 V rated value":"100 kA","at 400 V rated value":"25 kA","at 480 V rated value":"22 A","at 500 V rated value":"5 kA","at 600 V rated value":"22 A","at 690 V rated value":"2 kA","Design Of The Product":"For motor protection with overload relay function","Ground Fault Detection":"No","Phase Failure Detection":"Yes","For Main Current Circuit":"screw-type terminals","at 110/120 V rated value":"1.5 hp","at 200/208 V rated value":"7.5 hp","at 220/230 V rated value":"7.5 hp","at 460/480 V rated value":"15 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 5 to 6 mm","Size Of The Circuit-Breaker":"S0","Size Of The Screwdriver Tip":"Pozidriv size 2","at AC-3 rated value maximum":"690 V","Of The Main Contacts Typical":"100 000","at AC in hot operating state":"10.5 W","at AC-3 at 400 V rated value":"22 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":"22 A","Design Of The Auxiliary Switch":"laterally","Design Of The Overload Release":"thermal","Operating Frequency Rated Value":"50 ... 60 Hz","Operational Current Rated Value":"22 A","at AWG cables for main contacts":"2x (16 ... 12), 2x (14 ... 8)","Design Of The Short-Circuit Trip":"magnetic","For Auxiliary And Control Circuit":"screw-type terminals","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 AWG cables for auxiliary contacts":"2x (20 ... 16), 2x (18 ... 14)","Of The Auxiliary And Control Contacts":"M3","at AC in hot operating state per pole":"3.5 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 (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 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","For Main Contacts With Screw-Type Terminals":"2 ... 2.5 N·m","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","For Auxiliary Contacts With Screw-Type Terminals":"0.8 ... 1.2 N·m","Size Of Contactor Can Be Combined Company-Specific":"S00, S0","contact rating of auxiliary contacts according to UL":"C600 / R300","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Arrangement Of Electrical Connectors For Main Current Circuit":"Top and bottom","For Short-Circuit Protection Of The Auxiliary Switch Required":"fuse gL/gG: 6 A, quick: 10 A","Response Value Current Of Instantaneous Short-Circuit Trip Unit":"286 A","insulation voltage with degree of pollution 3 at AC rated value":"690 V","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"16 ... 22 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$64.77","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/cf0f1b991f3d89f264ffe666811acfb2.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=261768&mlfb=3RV2121-4CA10"},"ai":{"faq":[{"question":"What is the short-circuit breaking capacity of 3RV2121-4CA10 at 400 V?","answer":"The short-circuit breaking capacity is 25 kA at 400 V AC, with higher ratings at lower voltages (100 kA at 240 V) and lower ratings at higher voltages (5 kA at 500 V, 2 kA at 690 V)."},{"question":"Does 3RV2121-4CA10 include phase failure detection?","answer":"Yes, phase failure detection is included. It does not include ground fault detection."},{"question":"What are the mounting clearances required for 3RV2121-4CA10?","answer":"The breaker requires 50 mm clearance above and below, 30 mm to the sides, and zero clearance forwards or backwards. It mounts onto 35 mm DIN rail per DIN EN 60715."},{"question":"How do I get pricing and availability for 3RV2121-4CA10?","answer":"Submit an RFQ through this listing; the part is sourced to order through independent distribution, with current pricing and availability confirmed at quote time."},{"question":"Will 3RV2121-4CA10 drop into a panel specified around 3RV2023-4DA10 without rewiring?","answer":"Both are SIRIUS motor protection breakers in the same 65 mm wide DIN-rail footprint with screw terminals, so the physical fit and terminal spacing are identical. Verify the specific trip class and SCCR requirements of your application — the 3RV2121-4CA10 is Class 10 with 25 kA SCCR at 400 V, while the 3RV2023-4DA10 may differ in those parameters."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RV2121-4CA10","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/3RV2121-4CA10 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}}