{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RB3123-4NE0","brand":"Siemens","brandSlug":"siemens","productSlug":"3RB3123-4NE0","canonicalUrl":"https://aoctrl.com/siemens/3RB3123-4NE0","factsUrl":"https://aoctrl.com/api/mcp/products/3RB3123-4NE0","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS solid-state overload relay, 3RB3123-4NE0, S0 size, 1.25 A thermal current, adjustable trip class 5E/10E/20E/30E, 690 V rated, contactor mounting.","salesMarkdown":"## SIRIUS 3RB3123-4NE0 — Solid-State Overload Relay, S0 Size The Siemens 3RB3123-4NE0 is a SIRIUS solid-state overload relay in the S0 frame size, rated for a thermal current of 1.25 A at 480 V and 600 V, with a maximum rated voltage of 690 V. It mounts directly onto a contactor via the fastening method, saving panel space — no separate base needed. The trip class is adjustable across CLASS 5E, 10E, 20E, and 30E, so you match the relay to the motor start profile: fast trip for short acceleration, slow for high-inertia loads. The note on this unit reads \"for message 'tripped'\", which is the signaling contact output — it closes when the relay trips, feeding a discrete input on the PLC or annunciator. The auxiliary contact ratings cover common control voltages: 2 A at 24 V, 4 A at 120 V, 3 A at 230 V, and 0.3 A at 125 V, so it interfaces directly with 24 VDC or 120 VAC control circuits without an interposing relay. ## Mounting and Wiring — Contactor-Mounted, S0 Footprint The 3RB3123-4NE0 is designed for contactor mounting (fastening method: contactor mounting), meaning it clips onto the matching S0 contactor — no DIN rail required, though the assembly itself can be snapped onto a DIN rail if needed. Dimensions: 45 mm wide, 109 mm high, 85 mm deep. That 85 mm depth is the projection from the contactor face; account for it in enclosure depth when the panel door closes. Main circuit terminals are spring-loaded terminals accepting solid 2x (0.25... 1.5 mm²) or stranded up to 1x 10 mm². The screwdriver spec calls for Pozidriv PZ 2 with a shaft diameter of 5 to 6 mm. Mounting position is any — no restriction on orientation. Storage and transport range is -40 to +80 °C. Shock resistance is 15g / 11 ms per IEC 60068-2-27; the signaling contact in the tripped position is rated at 9g / 11 ms. Vibration resistance: 1-6 Hz, 15 mm amplitude; 6-500 Hz, 20 m/s², 10 cycles. Power dissipation per pole is 0.03 W — negligible heat contribution inside the enclosure, so no derating for adjacent relays in a dense panel.","metaTitle":"Siemens 3RB3123-4NE0 SIRIUS Solid-State Overload Relay, 1.25","metaDescription":"Siemens SIRIUS 3RB3123-4NE0 solid-state overload relay, 1.25 A thermal current, adjustable trip class 5E–30E, 690 V rated, S0 size, contactor mounting. Current lifecycle. Quoted to","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","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","During Storage":"-40 ... +80 °C","Thermal Current":"1.25 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":"1.25 A","at 600 V rated value":"1.25 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":"1.25 A","for AC motors at 500 V at 50 Hz":"0.12 ... 0.55 kW","for AC motors at 690 V at 50 Hz":"0.18 ... 0.75 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: 6 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: 6 A","at AWG cables for auxiliary contacts":"1x (24 ... 16), 2x (24 ... 16)","for 3-phase motors at 400 V at 50 Hz":"0.12 ... 0.37 kW","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":"1.25 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":"0.1 W","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"0.32 ... 1.25 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/ef776ed2dafa5ee6f4849c9796223a8c.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=176379&mlfb=3RB3123-4NE0","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RB3123-4NE0/alternatives.json"},"ai":{"faq":[{"question":"Where can I buy 3RB3123-4NE0 and how do I get a price?","answer":"This part is sourced to order through our independent distribution channel. Submit an RFQ; availability and current pricing are confirmed at quote time."},{"question":"What is the note 'for message tripped' on this relay?","answer":"The note indicates that the signaling contact (terminals 97/98) changes state when the relay trips, providing a dry-contact message to a PLC or indicator."},{"question":"What is the depth of 3RB3123-4NE0?","answer":"The depth is 85 mm, measured from the contactor mounting face."},{"question":"Will 3RB3123-4NE0 drop into a panel specified for 3RT1016-2AP02?","answer":"Both are S0-size contactor-mounted devices from the SIRIUS family, so the physical fit and mounting pattern are the same. The 3RT1016-2AP02 is a contactor; the 3RB3123-4NE0 is its matching overload relay — they are designed to mate directly."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RB3123-4NE0","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/3RB3123-4NE0 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-09-02T08:15:54.622Z","lastPublished":"2026-09-02T08:15:54.622Z","indexable":true}}