{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"5SP3720-2","brand":"Siemens","brandSlug":"siemens","productSlug":"5SP3720-2","canonicalUrl":"https://aoctrl.com/siemens/5SP3720-2","factsUrl":"https://aoctrl.com/api/mcp/products/5SP3720-2","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SENTRON 5SP3720-2, 1-pole miniature circuit breaker, 20 A rated current, E tripping characteristic, 25 kA breaking capacity at 230 V AC, busbar mount, 1.5 MW.","salesMarkdown":"The Siemens 5SP3720-2 is a SENTRON main miniature circuit breaker, single-pole, rated 20 A with an E tripping characteristic. It's built for residential and infrastructure panels — think meter cabinets, distribution boards, anything that needs a compact 1.5 MW-wide (about 27 mm) breaker that seals and feeds a busbar system. ## Breaking capacity — the number that matters Rated 25 kA at 230 V AC per EN 60898, and 25 kA as a rated value. For a residential or light-commercial service entrance, 25 kA gives you headroom over the typical 10–16 kA utility fault level — you don't want the breaker to fail open on a dead short downstream. ## E-curve — what that means on site E characteristic is a deliberate choice: it's a delayed trip curve, sitting between the standard C curve and the selective S curve. It holds through moderate inrush (think transformer magnetizing or motor starting on a small pump) but still clears fast on a hard fault. If you've been swapping out C-curve breakers that nuisance-trip on a cold-start load, this is the fix — it's designed for that middle ground. ## Temperature derating — don't ignore it Rated 20 A at 30 °C ambient, but at 40 °C it's 19 A, at 50 °C it's 18 A, and at 55 °C it's 17.5 A. The insulation voltage is 690 V, so voltage-wise there's headroom. ## Mounting and wiring — what fits in the van Fastens via busbar — clips onto the standard SENTRON busbar system, no DIN rail required (though it can sit on one if the panel is laid out that way). Terminals accept 2.5 mm² to 50 mm² solid or stranded, which covers everything from a 2.5 mm² lighting circuit to a 50 mm² main feed. The infeed is at the box terminal, and the outgoing feeder uses a spring-loaded terminal — no screwdriver needed on the load side, which saves time on a multi-way board. ## Environmental and mechanical toughness Shock-rated at 30 g for 11 ms (three hits), vibration tested per IEC 60068-2-6 at 2 g, 20 cycles from 5 to 150 Hz. IP40 with conductors connected — enough for a closed panel, not for washdown. Pollution degree 3, overvoltage category IV — that's the highest category for distribution boards, meaning it's designed for the incoming supply side, not just downstream branch circuits. ## Dimensions for panel layout Height 151.3 mm, depth 89.5 mm, enclosure depth 76.3 mm. At 1.5 modular width units (roughly 27 mm wide), it's narrower than a standard 2-MW breaker — useful when you're squeezing a main switch and several branch breakers into a compact meter panel. The depth means it clears most shallow enclosures, but check your gland plate clearance if the busbar runs behind it.","metaTitle":"Siemens 5SP3720-2 SENTRON MCB, 1P 20A E-Curve, 25 kA, 230V","metaDescription":"Siemens 5SP3720-2 SENTRON 1-pole miniature circuit breaker, 20 A, E characteristic, 25 kA breaking capacity at 230 V AC. Current production. Quoted to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":"Active","categoryPath":["1-Pole MCB (DIN Rail)"],"specifications":{"Depth":"89.5 mm","title":"5SP3720-2","Height":"151.3 mm","Maximum":"70 °C","Minimum":"-40 °C","Sealable":"Yes","Rated Value":"25 kA","description":"Main miniature circuit breaker (SHU), 1-pole, E 20A, 230/400 V (block with L1, L2, L3)","Number Of Poles":"1","Solid / Maximum":"50 mm²","Solid / Minimum":"2.5 mm²","lifecycle_stage":"current","Fastening Method":"Busbar","Shock Resistance":"30 g, at least 3 impacts, impact duration 11 ms","Product Brand Name":"SENTRON","Stranded / Maximum":"50 mm²","Stranded / Minimum":"2.5 mm²","Degree Of Pollution":"3","Product Designation":"Miniature circuit breaker","acc. to IEC 81346-2":"F","at AC / rated value":"20 A","protection class IP":"IP40, with connected conductors","Overvoltage Category":"IV","Design Of The Product":"Main miniature circuit breaker","Infeed At Box Terminal":"Yes","acc. to DIN EN 61346-2":"F","at 30 °C / rated value":"20 A","at 40 °C / rated value":"19 A","at 45 °C / rated value":"18.5 A","at 50 °C / rated value":"18 A","at 55 °C / rated value":"17.5 A","Depth / Of The Enclosure":"76.3 mm","Suitability For Operation":"Residential buildings/infrastructure","Number Of Modular Width Units":"1.5","Tripping Characteristic Class":"E","acc. to EN 60898 / rated value":"25 kA","Position / Of Power Supply Cord":"Stipulated by installation in the lower section of the meter panel","supply voltage / at AC / rated value":"230 V","insulation voltage (Ui) / rated value":"690 V","Surge Voltage Resistance / Rated Value":"6 kV","Outgoing Feeder Via Spring-Loaded Terminal":"Yes","vibration resistance / acc. to IEC 60068-2-6":"2 g, 20 frequency cycles 5 to 150 to 15 Hz","Display Version / For Switch Position Indicator":"OFF = green, ON = red","Mechanical Service Life (Switching Cycles) / Typical":"20 000"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/2f73d6f85e451aefcfeeb90e20a84c79.pdf","sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=250249&mlfb=5SP3720-2"},"ai":{"faq":[{"question":"What is the breaking capacity of the 5SP3720-2?","answer":"25 kA at 230 V AC per EN 60898. That's the rated value across the board — no derating needed for standard residential fault levels."},{"question":"What does the E tripping characteristic mean?","answer":"E-curve is a delayed trip between C and S curves — it holds through moderate inrush (transformer magnetizing, small motor starts) but clears fast on hard faults. Useful where C-curve breakers nuisance-trip on cold-start loads."},{"question":"What wire sizes does the 5SP3720-2 accept?","answer":"Solid 2.5 mm² to 50 mm², stranded 2.5 mm² to 50 mm². The infeed is a box terminal; the load side uses a spring-loaded terminal."},{"question":"How do I get pricing and availability for the 5SP3720-2?","answer":"Sourced and quoted to order through independent distribution. Submit an RFQ — current pricing and lead time are confirmed at quote time."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/5SP3720-2","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/5SP3720-2 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}}