{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RB3123-4QE0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RB3123-4QE0","canonicalUrl":"https://aoctrl.com/siemens/3RB3123-4QE0","factsUrl":"https://aoctrl.com/api/mcp/products/3RB3123-4QE0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RB3123-4QE0 solid-state overload relay, Size S0, 25 A thermal current, adjustable trip class 5E/10E/20E/30E, 690 V rated voltage, spring-loaded terminals, contactor mounting.","salesMarkdown":"It mounts directly onto a contactor, making it a drop-in fit for motor starter assemblies where space on the DIN rail is already committed to the contactor footprint. The trip class is field-adjustable among CLASS 5E, 10E, 20E, and 30E, so the same relay can be tuned for fast protection on short-cycle loads or slower curves for high-inertia starts without stocking multiple variants. The main current circuit uses spring-loaded terminals, accepting solid conductors 2x (0.25 to 1.5 mm²) or stranded up to 1x 10 mm². The auxiliary contact ratings span 2 A at 24 V, 4 A at 120 V, and 3 A at 230 V, covering typical PLC and relay logic inputs. ## Integration notes Fastening method is contactor mounting — the relay clips directly onto the matching SIRIUS contactor, not onto a DIN rail. This saves one DIN slot per starter and keeps the overload relay mechanically ganged to the contactor for coordinated trip indication. Mounting position is any, so the assembly can be oriented horizontally, vertically, or flat without derating the thermal current. The relay withstands vibration per IEC 60068-2-6 at 1-6 Hz, 15 mm amplitude and 6-500 Hz, 20 m/s² for 10 cycles, and shock at 15g / 11 ms on the main body. The signaling contact (97/98) in the tripped position is rated for 9g / 11 ms. ## Motor current setting and trip behavior The relay trips when the motor current exceeds the upper current setting value multiplied by 3.5, and resets when the current falls below the lower current setting value. This hysteresis prevents nuisance cycling on momentary overloads. The note for message \"tripped\" indicates that the signaling contact changes state when the relay has operated — useful for wiring a remote alarm or PLC input that confirms the overload condition. Power dissipation is 0.57 W per pole, so a three-pole installation adds about 1.7 W of heat inside the enclosure — negligible for most panels but worth checking if the cabinet is densely packed and poorly ventilated.","metaTitle":"Siemens 3RB3123-4QE0 SIRIUS solid-state overload relay, 25 A","metaDescription":"Siemens 3RB3123-4QE0 SIRIUS solid-state overload relay, Size S0, 25 A thermal current, adjustable trip class 5E-30E, 690 V rated voltage, contactor mounting. Sourced to order again","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":"3RB3123-4QE0","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":"0.57 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 6...25 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":"25 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":"25 A","at 600 V rated value":"25 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":"25 A","for AC motors at 500 V at 50 Hz":"4 ... 15 kW","for AC motors at 690 V at 50 Hz":"5.5 ... 22 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: 63 A, J: 100 A","Display Version For Switching Status":"Slide switch","Surge Voltage Resistance Rated Value":"6 kV","With Type Of Coordination 1 Required":"gG: 125 A, RK5: 100 A","for 3-phase motors at 400 V at 50 Hz":"3 ... 11 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":"25 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":"1.7 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"6 ... 25 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/69b2080791413b649f7adf070f4df7a6.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=79886&mlfb=3RB3123-4QE0"},"ai":{"faq":[{"question":"What is the depth of 3RB3123-4QE0?","answer":"The depth is 85 mm. Overall dimensions are 45 mm width, 109 mm height, and 85 mm depth."},{"question":"Will 3RB3123-4QE0 drop into a panel specified around 3RU2116-1FC1 without rewiring?","answer":"No. Both are Size S0 and share the same contactor mounting footprint, but the 3RB3123-4QE0 uses spring-loaded terminals while the 3RU2116-1FC1 uses screw terminals. The wiring method differs, so the panel would need terminal adaptation."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RB3123-4QE0","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/3RB3123-4QE0 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}}