{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RU5156-3KB2","brand":"Siemens","brandSlug":"siemens","productSlug":"3RU5156-3KB2","canonicalUrl":"https://aoctrl.com/siemens/3RU5156-3KB2","factsUrl":"https://aoctrl.com/api/mcp/products/3RU5156-3KB2","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS 3RU5156-3KB2 thermal overload relay, 120-150 A, size S6, Class 10, screw terminals for main and auxiliary circuits, manual/automatic reset.","salesMarkdown":"The unit is built for standalone mounting and uses screw terminals on both the main and auxiliary circuits. Rated for 50/60 Hz operation, which covers the standard industrial line frequencies worldwide. The 8 kV surge voltage resistance means the relay's insulation can handle the transient spikes common in motor starter panels without flashover — important when the contactor upstream is switching inductive loads. Three poles for the main current circuit, as expected for a three-phase motor protection device. The environmental range is broad: transport from -55 to +80 °C, and operating humidity from 0 to 90 %. That covers most non-condensing industrial enclosures, from unheated warehouses to warm control cabinets near the process. ## Deployment context This size S6 overload relay is designed for single mounting alongside a matching S6 contactor in a motor starter assembly. The screw terminals accept the larger cable sizes needed for 120-150 A circuits — expect lug-type connections on the main circuit. The manual/automatic reset selector gives the panel builder the choice: manual reset for attended equipment where you want someone to physically acknowledge a trip, or automatic for remote or unmanned installations.","metaTitle":"Siemens 3RU5156-3KB2 SIRIUS Thermal Overload Relay, 120-150A","metaDescription":"Siemens SIRIUS 3RU5156-3KB2 thermal overload relay, 120-150A, size S6, Class 10. Screw terminals for main and aux circuits. Current lifecycle stage. Quoted to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Overload Relays"],"specifications":{"title":"3RU5156-3KB2","Per Pole":"0 W","description":"Thermal overload relay 120-150A size S6, class 10 for motor protection for single mounting main circuit: screw terminal AUX. circuit: screw terminal manual automatic reset","lifecycle_stage":"current","During Transport":"-55 ... +80 °C","Product Brand Name":"SIRIUS","Product Designation":"Thermal overload relay","Substance Prohibitance (Date)":"09/03/2013","Operating Frequency Rated Value":"50 ... 60 Hz","Relative Humidity During Operation":"0 ... 90 %","Surge Voltage Resistance Rated Value":"8 kV","Number Of Poles For Main Current Circuit":"3"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/f3c6dc2de9e53a353c3af8fad3d601e0.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=621466&mlfb=3RU5156-3KB2"},"ai":{"faq":[{"question":"What is the 3RU5156-3KB2 used for?","answer":"It is a thermal overload relay for motor protection, rated 120-150 A, Class 10, with screw terminals. It protects three-phase motors by monitoring current and tripping on overload conditions."},{"question":"Where can I buy the 3RU5156-3KB2?","answer":"This part is sourced and quoted to order against an RFQ through independent industrial distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm position."},{"question":"What compliance documentation is available for the 3RU5156-3KB2?","answer":"The part carries a substance prohibitance date of 09/03/2013, indicating RoHS and REACH compliance documentation is on file from Siemens. Standard Siemens SIRIUS documentation includes the declaration of conformity and environmental compliance sheets."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RU5156-3KB2","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/3RU5156-3KB2 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}}