{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RV2121-4BA10","brand":"Siemens","brandSlug":"siemens","productSlug":"3RV2121-4BA10","canonicalUrl":"https://aoctrl.com/siemens/3RV2121-4BA10","factsUrl":"https://aoctrl.com/api/mcp/products/3RV2121-4BA10","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RV2121-4BA10, motor protection circuit breaker with integrated overload relay function, Class 10 trip class, 65 mm width, screw and snap-on mounting onto 35 mm DIN rail.","salesMarkdown":"## SIRIUS motor protection breaker with integrated overload relay It combines short-circuit and overload protection in a single device, sized for direct-on-line motor starting applications. This matches the thermal withstand curve of most IEC and NEMA design B motors. Ground fault detection is not included; that function would need a separate RCD or GFCI module upstream. For higher fault currents, the breaker requires upstream backup fuses: at 400 V, gL/gG 63 A fuses; at 500 V and 690 V, gL/gG 50 A fuses. This is standard for motor protection breakers — the fuses handle the high-energy arc while the breaker provides the thermal overload curve. Motor horsepower ratings are specified per voltage: 3 hp at 230 V, 1.5 hp at 110/120 V, and 7.5 hp at 200/208 V. These are the maximum motor sizes the breaker can protect at those line voltages — oversizing the breaker to a larger motor would lose overload protection. Width is 65 mm. Mounting position is any. The zero forward/backward clearance means it can be stacked flush against a back panel or enclosure door — useful in shallow enclosures. Dimensions are 97 mm deep, 65 mm wide, 97 mm high. The depth is the critical dimension for shallow enclosures — verify your gland plate or door clearance allows the full 97 mm plus wiring space. Main circuit terminals are screw-type, accepting 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) solid or stranded conductors. Terminal screw size is M4. Strip length and torque values should follow the manufacturer's installation instructions. ## Environmental and operational limits Maximum switching frequency is 15 operations per hour at AC-3 and AC-3e duty. This is typical for a motor protection breaker — it is not designed for frequent switching like a contactor. For applications requiring more than 15 starts per hour, use a contactor for the switching and this breaker only for backup protection.","metaTitle":"Siemens 3RV2121-4BA10 SIRIUS Motor Protection CB, Class 10,","metaDescription":"Siemens 3RV2121-4BA10 SIRIUS motor protection circuit breaker with overload relay function. Class 10 trip, 25 kA at 400 V, phase failure detection. DIN rail mount. Sourced 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":"65 mm","title":"3RV2121-4BA10","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 13...20 A N-release 260 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":"20 A","at 500 V rated value":"5 kA","at 600 V rated value":"20 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":"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 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":"20 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":"20 A","Design Of The Auxiliary Switch":"laterally","Design Of The Overload Release":"thermal","Operating Frequency Rated Value":"50 ... 60 Hz","Operational Current Rated Value":"20 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":"260 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":"13 ... 20 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/d057263ae6a8173cb82b435592239b47.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=306485&mlfb=3RV2121-4BA10"},"ai":{"faq":[{"question":"What clearance distances are required around 3RV2121-4BA10?","answer":"50 mm above and below, 30 mm at the sides, and zero forwards or backwards. The zero forward/backward clearance allows flush mounting against a back panel or enclosure door."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RV2121-4BA10","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/3RV2121-4BA10 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}}