{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RH1921-1CA01-ZW98","brand":"Siemens","brandSlug":"siemens","productSlug":"3RH1921-1CA01-ZW98","canonicalUrl":"https://aoctrl.com/siemens/3RH1921-1CA01-ZW98","factsUrl":"https://aoctrl.com/api/mcp/products/3RH1921-1CA01-ZW98","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RH1921-1CA01-ZW98 auxiliary switch, S0 size, snap-on front mount, 10 mm wide, 10 A AC-12 / 6 A at 24 V AC-15, mirror contact per IEC 60947-4-1.","salesMarkdown":"It's the add-on block that gives you isolated N/O or N/C feedback contacts for your PLC inputs, status lamps, or safety circuits — without taking up extra DIN rail space. Width is just 10 mm, so it stacks tight alongside the contactor body. Depth of 51 mm and height of 38 mm keep it inside the contactor's own envelope — no panel layout surprises when you're swapping a block in an existing build. ## What the contact ratings actually mean for your circuit Rated 10 A at AC-12 (resistive loads like heaters or lamps) and 6 A at AC-15 (solenoid and contactor coils) across 24 V and 230 V. For DC control circuits the ratings drop with voltage: 6 A at 24 V DC, 2 A at 48 V and 60 V, 1 A at 110 V, 0.3 A at 220 V. That's typical for a compact auxiliary block — the DC arc is harder to extinguish, so you derate accordingly. At higher AC voltages the switch still delivers: 3 A at 400 V and 1 A at 690 V AC-15. ## Mirror contact — why it matters for safety circuits This switch carries a mirror contact per IEC 60947-4-1 when used with the 3RT1 contactor range. That means the N/C contact is mechanically linked to the N/O contact — if the N/O welds shut, the N/C stays open. Safety-rated circuits (like emergency stop feedback or guard door monitoring) require this to guarantee a reliable off-state signal. No REACH or UL listing is stated in the available records, but the SIRIUS series typically carries UL/CSA certification — confirm the specific mark with the factory if your panel requires it. ## Wiring and installation notes Terminals accept 2 x 0.5 to 1.5 mm² solid or stranded, or 2 x 0.75 to 2.5 mm² with ferrules. For AWG, that's 2 x 20–16 and 2 x 18–14. The spring-cage style holds firm under vibration — no screw retorque needed on a crusher or conveyor panel. Snap-on mounting means you push it onto the front of the S0 contactor until it clicks. No tools, no DIN rail. The IP20 front protection keeps fingers away from live terminals inside the enclosure. Contact reliability is specified at 1 faulty switching per 100 million at 17 V, 1 mA — that's the dry-circuit performance for low-energy PLC inputs.","metaTitle":"Siemens 3RH1921-1CA01-ZW98 SIRIUS Auxiliary Switch, S0, 10 A","metaDescription":"Siemens SIRIUS 3RH1921-1CA01-ZW98 auxiliary switch for S0 contactors. Snap-on front mount, 10 mm wide, rated 6 A at 24 V AC-15, mirror contact per IEC 60947-4-1. Active production,","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Contactors"],"specifications":{"Depth":"51 mm","Width":"10 mm","Height":"38 mm","at 24 V":"6 A","at 48 V":"2 A","at 60 V":"2 A","at 110 V":"1 A","at 125 V":"0.9 A","at 220 V":"0.3 A","at 230 V":"6 A","at 250 V":"0.3 A","at 400 V":"3 A","During Storage":"-55 ... +80 °C","lifecycle_stage":"current","During Operation":"-25 ... +60 °C","Fastening Method":"snap-on mounting","Product Category":"Auxiliary switch","Size Of Contactor":"S0","Solid Or Stranded":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)","Product Brand Name":"SIRIUS","Product Designation":"auxiliary switch","Suitability For Use":"Contactor relay and power contactor","at 24 V rated value":"10 A","at 60 V rated value":"4.7 A","at 110 V rated value":"3 A","at 220 V rated value":"1.2 A","at 440 V rated value":"0.5 A","at 600 V rated value":"0.26 A","Design Of The Product":"for snapping onto the front","Instantaneous Contact":"0","Substance Prohibitance (Date)":"07/01/2006","protection class IP on the front":"IP20","Surge Voltage Resistance Rated Value":"6 kV","for AWG cables for auxiliary contacts":"2x (20 ... 16), 2x (18 ... 14)","Finely Stranded With Core End Processing":"2x (0.5 ... 1.5 mm²), 2x (0.75 ... 2.5 mm²)","Contact Reliability Of Auxiliary Contacts":"1 faulty switching per 100 million (17 V, 1 mA)","mirror contact according to IEC 60947-4-1":"Yes; with 3RT1","operational current at AC-15 at 690 V rated value":"1 A","Mechanical Service Life (Operating Cycles) Typical":"10 000 000","operational current of auxiliary contacts at AC-12 maximum":"10 A","Type Of Electrical Connection For Auxiliary And Control Circuit":"screw-type terminals","insulation voltage with degree of pollution 3 at AC rated value":"690 V","number of CO contacts of auxiliary contacts instantaneous contact":"0","AWG number as coded connectable conductor cross section for auxiliary contacts":"20 ... 14"}},"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=91397&mlfb=3RH1921-1CA01-ZW98","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RH1921-1CA01-ZW98/alternatives.json"},"ai":{"faq":[{"question":"Will the 3RH1921-1CA01-ZW98 drop into a panel built around the 3RT1016-2AP02 without rewiring?","answer":"Yes, if the 3RT1016-2AP02 is an S0-size contactor. The 3RH1921-1CA01-ZW98 is designed to snap onto the front of any S0 contactor or contactor relay in the SIRIUS range. The terminal assignments are identical across the S0 auxiliary switch family, so no rewiring is needed — just snap it on and land the wires."},{"question":"What is the depth of the 3RH1921-1CA01-ZW98?","answer":"51 mm. That's the depth from the front face of the contactor to the back of the auxiliary switch once snapped on."},{"question":"What is the width of the 3RH1921-1CA01-ZW98?","answer":"10 mm. It's a single-width block that fits alongside the contactor body without protruding beyond the S0 envelope."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RH1921-1CA01-ZW98","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/3RH1921-1CA01-ZW98 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}}