{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SM2646-8","brand":"Siemens","brandSlug":"siemens","productSlug":"5SM2646-8","canonicalUrl":"https://aoctrl.com/siemens/5SM2646-8","factsUrl":"https://aoctrl.com/api/mcp/products/5SM2646-8","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON, selective RCD unit, 5SM2646-8, 4-pole, 63 A, 300 mA Type A, IP20.","salesMarkdown":"## Selective RCD for downstream coordination The Siemens 5SM2646-8 is a selective RCD unit from the SENTRON family, designed to provide time-delayed ground-fault protection so a downstream RCD trips first — the selective design keeps this unit from nuisance-tripping on transient faults and ensures the upstream device stays closed during a downstream fault. Rated at 63 A AC and 300 mA Type A residual fault current, it handles the main feeder or sub-feed in a distribution board where coordination with branch RCDs is required. Four-pole construction (4 poles) covers three-phase plus neutral, with a 50/60 Hz operating frequency and an insulation voltage (Ui) of 460 V. The 300 mA tripping threshold is higher than a standard 30 mA RCD — this is intentional for a selective (time-delayed) device. It allows downstream 30 mA RCDs to clear a fault first, while the 5SM2646-8 waits through the delay and only trips if the fault persists. That selectivity is what protects the rest of the panel from a full blackout on a branch fault. Type A detection means it responds to AC sinusoidal residual currents and pulsed DC residual currents up to 6 mA smooth DC — covers the typical rectified waveforms from single-phase power supplies and VFDs you'd find in a mixed-load panel. Temperature derating is published: 58.6 A at 40 °C, dropping to 50.4 A at 70 °C. Factor that into the load schedule. Fastening method is standard REG (regular) snap-on. Supply connection can be top or bottom. The unit is not sealable and has no adjustable time delay or adjustable fault current — it's a fixed-setting selective device, no field calibration required.","metaTitle":"Siemens 5SM2646-8 SENTRON RCD Unit, 63A, 300mA, Type A","metaDescription":"Siemens 5SM2646-8 SENTRON selective RCD unit, 4-pole, 63 A rated, 300 mA Type A fault current, IP20. Current lifecycle. Available to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["Residual Current Breakers (RCCB/RCBO)"],"specifications":{"Depth":"70 mm","Width":"123 mm","title":"5SM2646-8","Height":"90 mm","Maximum":"75 °C","Minimum":"-40 °C","Sealable":"No","description":"RC unit for 5SL4, 4-pole, type A, selective, In: 63 A, 300 mA, Un AC: 400 V","Design Of Pole":"4 poles","Number Of Poles":"4","lifecycle_stage":"current","Fastening Method":"REG","Mounting Position":"any","at AC rated value":"63 A","Installation Depth":"70 mm","Product Brand Name":"SENTRON","Product Variations":"for 5SL4","Degree Of Pollution":"2","Product Designation":"RCD-unit","protection class IP":"IP20, if the distribution board is installed, with connected conductors","Overvoltage Category":"III","Design Of The Product":"Selective","Residual Current Type":"A","at 40 °C rated value":"58.6 A","at 45 °C rated value":"58.59 A","at 50 °C rated value":"56.7 A","at 55 °C rated value":"54.81 A","at 60 °C rated value":"53.55 A","at 65 °C rated value":"52.29 A","at 70 °C rated value":"50.4 A","OFF-delay time adjustable":"No","For Testing Equipment Minimum":"195 V","Number Of Modular Width Units":"3","Position Of Power Supply Cord":"top or bottom","Rated Fault Current Adjustable":"No","Protection Function False Tripping":"Yes","Tripping Fault Current Rated Value":"300 mA","insulation voltage (Ui) rated value":"460 V","Surge Current Resistance Rated Value":"5 kA","Surge Voltage Resistance Rated Value":"4 000 V","Value Range Of The Operating Frequency":"50/60 Hz","Type Of Voltage Of The Operating Voltage":"AC","Value Range Of The Supply Voltage Frequency":"50 Hz","Mechanical Service Life (Operating Cycles) Typical":"10 000","for rated value of the current at AC in hot operating state per pole":"3 W"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/af93c57b432286ec6a4b7162e4c40580.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=60806&mlfb=5SM2646-8"},"ai":{"faq":[{"question":"What is the difference between 5SM2646-8 and 5SL4363-7?","answer":"The 5SL4363-7 is a standard (non-selective) RCD, while the 5SM2646-8 is selective — meaning it has a built-in time delay to coordinate with downstream RCDs. If your panel requires selectivity on the main feeder, the 5SM2646-8 is the correct choice; the 5SL4363-7 would trip simultaneously with downstream devices."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SM2646-8","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/5SM2646-8 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}}