{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SM3344-0KL","brand":"Siemens","brandSlug":"siemens","productSlug":"5SM3344-0KL","canonicalUrl":"https://aoctrl.com/siemens/5SM3344-0KL","factsUrl":"https://aoctrl.com/api/mcp/products/5SM3344-0KL","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SM3 series, RCCB, 4-pole, type AC, In: 40 A, IΔn: 30 mA, Un: 400 V AC, 10 kA SCCR, DIN rail mount, N left.","salesMarkdown":"The Siemens 5SM3344-0KL is a 4-pole SENTRON residual current operated circuit breaker (RCCB), type AC, rated 40 A with a 30 mA trip threshold at 400 V AC — the standard residential and light commercial ground-fault protection package for three-phase networks where neutral is brought in on the left side of the device. The 30 mA sensitivity is the common touch-safe threshold per IEC 60364, meaning it clears leakage currents that would be hazardous to a person making contact with an energized enclosure. It is an instantaneous (non-time-delayed) design — no intentional delay before tripping on a ground fault — so it responds immediately to sinusoidal AC residual currents at the mains frequency of 50 Hz. The 30 mA trip threshold is the standard for personal protection against electric shock; it will not coordinate with a 30 mA upstream RCCB — if selectivity is needed between two RCCBs, the downstream unit must be a time-delayed (S-type) or a lower-threshold device. Ambient temperature range of -5 to +45 °C covers most indoor panel environments, but at sustained temperatures above 40 °C the continuous current rating should be derated per the manufacturer's thermal curve — the 40 A rating is at a reference ambient, typically 30 or 35 °C. Snaps onto standard DIN rail (REG profile), occupies 4 width units (roughly 72 mm), and installs in any orientation — top or bottom feed, horizontal or vertical rail, no restriction. Installation depth is 70 mm from the rail — fits flush in a standard 125 mm deep distribution board; check the gland plate clearance if you're running conductors behind the device. Terminals accept solid or stranded conductors from 1.5 to 25 mm² — covers everything from a 2.5 mm² lighting circuit tail up to a 16 mm² feeder; tighten to 2.5 to 3 N·m with a screwdriver, no special torque tool needed. The N-left variant means the neutral pole is on the left side of the device when viewed from the front — if you're replacing an existing RCCB that has neutral on the right, you'll need to swap the incoming and outgoing conductors or use a different variant.","metaTitle":"Siemens 5SM3344-0KL SENTRON RCCB, 4P, 40 A, 30 mA, 400 V AC","metaDescription":"Siemens 5SM3344-0KL SENTRON RCCB, 4-pole, type AC, 40 A rated, 30 mA trip, 400 V AC, 10 kA SCCR, DIN rail. Current lifecycle stage. Sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Residual Current Breakers (RCCB/RCBO)"],"specifications":{"Solid":"1.5 ... 25 mm²","Stranded":"1.5 ... 25 mm²","Rated Value":"50 Hz","Mounting type":"DIN rail (REG)","During Storage":"-40 ... +75 °C","Number of poles":"4","lifecycle_stage":"current","Mounting position":"any","Installation depth":"70 mm","Product brand name":"SENTRON","Product variations":"N left","Ambient temperature":"-5 ... +45 °C","Operating frequency":"50Hz","Product designation":"RCCB","Protection class IP":"IP20, if the distribution board is installed, with connected conductors","Overvoltage category":"III","Design of the product":"Instantaneous","Number of width units":"4","Type of fault current":"AC","circuit-breaker / Design":"5SM3","Short-circuit current rating":"10 kA","Current / at AC / rated value":"40 A","Product feature / silicon-free":"Yes","Position / of power supply cord":"top or bottom","Protection against electrical shock":"Finger and back-of-hand safe","Supply voltage / at AC / rated value":"400 V","Switching function / short-term delayed":"No","Tripping residual current / rated value":"30 mA","Tightening torque / with screw-type terminals":"2.5 ... 3 N·m","Size of installation devices / acc. to DIN 43880":"1","Supply voltage / for testing equipment / minimum":"100 V","Mechanical service life (switching cycles) / typical":"10 000"}},"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=250936&mlfb=5SM3344-0KL","alternativesUrl":"https://aoctrl.com/api/mcp/products/5SM3344-0KL/alternatives.json"},"ai":{"faq":[{"question":"What is the closest functional second-source for 5SM3344-0KL?","answer":"The Siemens 5SY4304-7CV is a 3-pole MCB with a 15 kA SCCR and C-curve trip characteristic — it is not a direct functional replacement for a 4-pole 30 mA RCCB. The 5SM3344-0KL is the correct RCCB for ground-fault protection; the 5SY series fills a different role (overcurrent protection only)."},{"question":"Will 5SM3344-0KL drop into a panel specified around 5SY4304-7CV?","answer":"No. The 5SY4304-7CV is a 3-pole MCB (54 mm wide, 3 width units) while the 5SM3344-0KL is a 4-pole RCCB (72 mm wide, 4 width units). The depth (70 mm) and DIN rail mounting are the same, but the width, number of poles, and function (ground-fault vs overcurrent protection) are different — the panel layout and wiring must be revised."},{"question":"What conductor sizes does 5SM3344-0KL accept?","answer":"Solid and stranded conductors from 1.5 to 25 mm². The screw terminals tighten to 2.5 to 3 N·m."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SM3344-0KL","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/5SM3344-0KL 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}}