{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RB3123-4RE0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RB3123-4RE0","canonicalUrl":"https://aoctrl.com/siemens/3RB3123-4RE0","factsUrl":"https://aoctrl.com/api/mcp/products/3RB3123-4RE0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RB3123-4RE0 solid-state overload relay, Size S0, 0.4 A rated operational current, 690 V rated insulation voltage, adjustable trip classes 5E, 10E, 20E, 30E, spring-loaded terminals, contactor mounting.","salesMarkdown":"## Adjustable trip class — CLASS 5E, 10E, 20E, 30E The 3RB3123-4RE0: Trip class is field-selectable among 5E, 10E, 20E, and 30E. This lets you match the relay's thermal curve to the motor start profile: a 5E setting trips fast (good for short-duration starts like centrifugal pumps), while 30E allows longer inrush (needed for high-inertia loads like conveyors or crushers). The relay trips when motor current exceeds the upper current setting value x 3.5 (maximum) and resets when current drops below the lower current setting value (minimum). This hysteresis prevents nuisance re-closure on a still-running motor. The S0 footprint (width 45 mm, height 109 mm, depth 85 mm) is the standard Siemens frame size for contactors up to about 40 A. It occupies one 45 mm-wide slot on the DIN rail when mounted to its matching contactor. Main circuit terminals accept solid wire 2x (0.25 … 1.5 mm²) or stranded up to 1x 10 mm². The screwdriver specification is Pozidriv PZ2 with a shaft diameter of 5 to 6 mm. ## Auxiliary contact ratings and environmental limits The signalling contact (for message 'tripped') is rated 2 A at 24 V, 4 A at 120 V, and 3 A at 230 V — these cover typical PLC input and relay coil loads across common control voltages. Operating temperature range is -25 … +60 °C with full temperature compensation over that span. Storage and transport range is -40 … +80 °C. Vibration resistance is 1–6 Hz at 15 mm amplitude, 6–500 Hz at 20 m/s² for 10 cycles; shock resistance is 15 g / 11 ms.","metaTitle":"Siemens 3RB3123-4RE0 SIRIUS solid-state overload relay, S0","metaDescription":"Siemens 3RB3123-4RE0 SIRIUS solid-state overload relay, S0 size, 0.4 A rated operational current, adjustable trip classes 5E/10E/20E/30E.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Overload Relays"],"specifications":{"Note":"for message \"tripped\"","Depth":"85 mm","Solid":"2x (0.25 ... 1.5 mm²)","Width":"45 mm","title":"3RB3123-4RE0","Height":"109 mm","Maximum":"IMotor < upper current setting value x 3.5","Minimum":"IMotor > lower current setting value","at 24 V":"2 A","at 60 V":"0.55 A","Per Pole":"0.03 W","Stranded":"1x 10 mm²","at 110 V":"0.3 A","at 120 V":"4 A","at 125 V":"0.3 A","at 220 V":"0.11 A","at 230 V":"3 A","Trip Class":"CLASS 5E, 10E, 20E and 30E adjustable","Rated Value":"690 V","description":"Overload relay 0.1...0.4 A Electronic For motor protection Size S0, Class 5...30 Contactor mounting Main circuit: Spring-type terminal Auxiliary circuit: Spring-type terminal Manual-Automatic-Reset Internal ground fault detection","During Storage":"-40 ... +80 °C","Thermal Current":"0.4 A","lifecycle_stage":"current","During Operation":"-25 ... +60 °C","During Transport":"-40 ... +80 °C","Fastening Method":"Contactor mounting","Shock Resistance":"15g / 11 ms","For Main Contacts":"M4","Mounting Position":"any","Solid Or Stranded":"2x (0,25 ... 1,5 mm²)","Product Brand Name":"SIRIUS","Product Designation":"solid-state overload relay","Vibration Resistance":"1-6 Hz, 15 mm; 6-500 Hz, 20 m/s²; 10 cycles","at 480 V rated value":"0.4 A","at 600 V rated value":"0.4 A","Size Of Overload Relay":"S0","For Main Current Circuit":"spring-loaded terminals","Temperature Compensation":"-25 ... +60 °C","Design Of Screwdriver Shaft":"Diameter 5 to 6 mm","Size Of The Screwdriver Tip":"Pozidriv PZ 2","according to IEC 60068-2-27":"15g / 11 ms; Signaling contact 97 / 98 in position \"Tripped\": 9g / 11 ms","at AC-3e rated value maximum":"690 V","Substance Prohibitance (Date)":"10/01/2009","Design Of The Auxiliary Switch":"integrated","Design Of The Overload Release":"electronic","Operating Frequency Rated Value":"50 ... 60 Hz","Operational Current Rated Value":"0.4 A","for AC motors at 500 V at 50 Hz":"0.04 ... 0.12 kW","for AC motors at 690 V at 50 Hz":"0.06 ... 0.18 kW","for remote-reset function at DC":"24 V","For Auxiliary And Control Circuit":"spring-loaded terminals","Between Main And Auxiliary Circuit":"690 V","Relative Humidity During Operation":"10 ... 95 %","With Type Of Assignment 2 Required":"gG: 4 A","Display Version For Switching Status":"Slide switch","Surge Voltage Resistance Rated Value":"6 kV","With Type Of Coordination 1 Required":"gG: 35 A, RK5: 3 A","for 3-phase motors at 400 V at 50 Hz":"0.04 ... 0.09 kW","for AWG cables for auxiliary contacts":"1x (24 ... 16), 2x (24 ... 16)","Between Auxiliary And Auxiliary Circuit":"300 V","due to burst according to IEC 61000-4-4":"2 kV (power ports), 1 kV (signal ports) corresponds to degree of severity 3","reference code according to IEC 81346-2":"F","Finely Stranded With Core End Processing":"2x (0.25 ... 1.5 mm²)","Number Of Poles For Main Current Circuit":"3","Finely Stranded Without Core End Processing":"2x (0.25 ... 1.5 mm²)","number of CO contacts for auxiliary contacts":"0","number of NC contacts for auxiliary contacts":"1","number of NO contacts for auxiliary contacts":"1","operational current at AC-3e at 400 V rated value":"0.4 A","Size Of Contactor Can Be Combined Company-Specific":"S0","electrostatic discharge according to IEC 61000-4-2":"6 kV contact discharge / 8 kV air discharge","Type Of Voltage Supply Via Input/Output Link Master":"No","contact rating of auxiliary contacts according to UL":"B600 / R300","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Response Time Of The Grounding Protection In Settled State":"1 000 ms","Response Value Current Of The Grounding Protection Minimum":"0.75 x IMotor","Arrangement Of Electrical Connectors For Main Current Circuit":"Top and bottom","For Short-Circuit Protection Of The Auxiliary Switch Required":"fuse gG: 6 A","insulation voltage with degree of pollution 3 at AC rated value":"690 V","Product Component Removable Terminal For Auxiliary And Control Circuit":"Yes","power loss [W] for rated value of the current at AC in hot operating state":"0.1 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"0.1 ... 0.4 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$101.60","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/c35359505f532544b73bdaca436aa9d8.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=437320&mlfb=3RB3123-4RE0"},"ai":{"faq":[],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RB3123-4RE0","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/3RB3123-4RE0 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}}