{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RH1253-1BB40","brand":"Siemens","brandSlug":"siemens","productSlug":"3RH1253-1BB40","canonicalUrl":"https://aoctrl.com/siemens/3RH1253-1BB40","factsUrl":"https://aoctrl.com/api/mcp/products/3RH1253-1BB40","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS auxiliary contactor, 3RH1253-1BB40, 24 VDC coil, 10 A AC-12 rated, size S00, screw and snap-on mounting.","salesMarkdown":"Rated 10 A at AC-12 (resistive loads at 24 V), it handles the typical pilot-duty and PLC-input switching. The switching capacity drops predictably with voltage: 6 A at 230 V, 3 A at 400 V, 1 A at 690 V. For DC switching, it manages 10 A at 24 V, 1 A at 110 V, and 0.27 A at 220 V — useful for interposing relays in DC control loops. Surge voltage resistance at 6 kV and pollution degree 3 suit it for industrial environments where transients and contamination are routine. Depth is 111 mm, so account for that behind the gland plate when routing wiring. This helps when fitting into crowded sub-panels or angled enclosures. Wire termination accepts solid conductors: 2x 0.5–1.5 mm², 2x 0.75–2.5 mm², or 2x 4 mm². The spring-cage terminals (implied by the SIRIUS S00 design) hold firmly without retorquing — good for high-vibration environments. Shock resistance is 10g / 5 ms and 5g / 10 ms, covering most industrial machinery vibration profiles. IP20 on the front — finger-safe but not washdown-rated. Suitable for enclosed panels where the front is the only accessible surface. Above that, air density affects dielectric withstand and cooling — consult the thermal curve if your site exceeds this. ## Sourcing and fit decision If you are cross-referencing from a 3RT1015-1BB42, note that the 3RT is a power contactor, not an auxiliary contactor. The 3RH1253-1BB40 provides auxiliary contacts for signaling and interlocking, not main power switching. The coil voltage (24 VDC) and S00 frame size are shared, but the function differs — verify the circuit role before substituting.","metaTitle":"Siemens 3RH1253-1BB40 SIRIUS Auxiliary Contactor, 24 VDC, 10","metaDescription":"Siemens 3RH1253-1BB40 SIRIUS auxiliary contactor, 24 VDC coil, 10 A AC-12 rated, size S00. Current lifecycle stage. Sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"111 mm","Solid":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²), 2x 4 mm²","Width":"45 mm","Height":"57.5 mm","Maximum":"2 000 m","At The Side":"0 mm","Rated Value":"24 V","On The Front":"IP20","Initial Value":"0.8","Mounting type":"screw and snap-on mounting","During Storage":"-55 ... +80 °C","Leading Contact":"0","lifecycle_stage":"current","Auxiliary switch":"No","During Operation":"-25 ... +60 °C","During Transport":"-55 ... +80 °C","Full-scale value":"1.1","Shock resistance":"10g / 5 ms and 5g / 10 ms","Delayed Switching":"0","Lagging Switching":"0","Mounting position":"+/-180° rotation possible on vertical mounting surface; can be tilted forward and backward by +/- 22.5° on vertical mounting surface","Size of contactor":"S00","Product brand name":"SIRIUS","Degree of pollution":"3","Product designation":"Auxiliary contactor","at 24 V rated value":"10 A","Of Contactor Typical":"10 000 000","at 110 V rated value":"1 A","at 220 V rated value":"0.27 A","at 230 V rated value":"6 A","at 400 V rated value":"3 A","at 500 V rated value":"2 A","at 690 V rated value":"1 A","Instantaneous Contact":"5","For Auxiliary Contacts":"0","Make-Before-Break Switching":"0","Closing power of magnet coil at DC":"3.2 W","Holding power of magnet coil at DC":"3.2 W","Operating current at AC-12 maximum":"10 A","Surge voltage resistance rated value":"6 kV","Reference code acc. to DIN EN 81346-2":"K","with low demand rate acc. to SN 31920":"40 %","with high demand rate acc. to SN 31920":"75 %","Finely Stranded With Core End Processing":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)","at AWG conductors for auxiliary contacts":"2x (20 ... 16), 2x (18 ... 14), 1x 12","Contact reliability of auxiliary contacts":"1 faulty switching per 100 million (17 V, 1 mA)","For Auxiliary And Control Current Circuit":"screw-type terminals","Of Auxiliary Contacts Instantaneous Contact":"0","Number of NC contacts for auxiliary contacts":"3","Number of NO contacts for auxiliary contacts":"5","with degree of pollution 3 at AC rated value":"690 V","Type of voltage of the control supply voltage":"DC","Identification number and letter for switching elements":"53 E","For Short-Circuit Protection Of The Auxiliary Switch Required":"fuse gL/gG: 10 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=58551&mlfb=3RH1253-1BB40","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RH1253-1BB40/alternatives.json"},"ai":{"faq":[{"question":"What are the key ratings for this auxiliary contactor?","answer":"24 VDC coil drawing 3.2 W, rated 10 A at AC-12 (24 V). Switching capacity varies by voltage: 6 A at 230 V, 3 A at 400 V, 1 A at 690 V AC; 10 A at 24 V, 1 A at 110 V, 0.27 A at 220 V DC. Mechanical endurance is 10,000,000 cycles."},{"question":"Will 3RH1253-1BB40 fit in a panel designed for 3RT1015-1BB42?","answer":"Both are S00 frame size and share the same 45 mm width, 57.5 mm height, and DIN-rail mounting. The 3RH1253-1BB40 is an auxiliary contactor for signaling, not a power contactor like the 3RT1015-1BB42. Mechanically it fits, but electrically it serves a different function — verify the circuit role before substituting."},{"question":"What wire sizes does the 3RH1253-1BB40 accept?","answer":"Solid conductors: 2x 0.5–1.5 mm², 2x 0.75–2.5 mm², or 2x 4 mm² per terminal."},{"question":"What is the depth of this component?","answer":"111 mm from the mounting surface to the front of the device."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RH1253-1BB40","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/3RH1253-1BB40 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}}