{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"S203-K50","brand":"ABB","brandSlug":"abb","productSlug":"S203-K50","canonicalUrl":"https://aoctrl.com/abb/S203-K50","factsUrl":"https://aoctrl.com/api/mcp/products/S203-K50","rawCanonicalId":null},"summary":{"shortDescription":"ABB S200 series S203-K50, 3-pole K-curve miniature circuit breaker, 50 A, 480Y/277 V AC, 6 kA interrupting capacity, UL 1077 supplemental protector, DIN rail mount.","salesMarkdown":"## S203-K50: 50 A K-Curve Supplemental Protector for 480Y/277 V Panels It's built as a UL 1077 supplemental protector for 480Y/277 V AC circuits, with a 6 kA interrupting capacity. The 480Y/277 V AC rating confirms it's rated for line-to-line 480 V and line-to-neutral 277 V wye systems — common in North American commercial and light industrial panels. The K-curve is the key selection parameter: it's the middle ground between C and D curves, with magnetic trip at 8–12× In, so it holds through motor start-up but still protects against hard shorts. ## Deployment & Integration The S200 series footprint is compact, so it fits tightly in multi-pole groups. Use it as a supplemental protector in branch circuits downstream of a main breaker or fused disconnect, typically in control panels, HVAC units, or machine-tool enclosures where UL 1077 listing is accepted.","metaTitle":"ABB S203-K50 50A 3-Pole K-Curve DIN Rail MCB, 480Y/277V","metaDescription":"ABB S203-K50 50A 3-pole K-curve miniature circuit breaker, 480Y/277V AC, 6 kAIC, UL 1077 supplemental protector. Current lifecycle stage, sourced to order. Request RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["3-Pole MCB (DIN Rail)"],"specifications":{"Amps":"50","Type":"Trip Curve K","Poles":"3","title":"S203-K50","Mounting":"DIN Rail","Volts AC":"480","description":"50A, 480Y/277V, 6 kAIC, B-Curve, UL 1077 CB|Miniature Circuit Breaker, 50 Amps, 480Y/277V AC. K - Curve. 6 kAIC. S200 Series. Supplemental Protectors. UL 1077, CSA 22.2.","lifecycle_stage":"current","Interrupt Rating AC":"6 kA"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":"$22.23","stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/1b888e9d473400bd32917551d1de57a0.pdf","sourceUrl":null},"ai":{"faq":[{"question":"What is S203-K50's listed amps and trip curve?","answer":"The S203-K50 is rated 50 A continuous with a K trip curve. The K-curve provides magnetic trip at 8–12 times rated current, suitable for loads with moderate inrush."},{"question":"Will S203-K50 drop into a panel specified around S203-D13 without rewiring?","answer":"Both are 3-pole S200 series breakers with the same DIN-rail footprint, so the S203-K50 will physically fit the same panel location as an S203-D13. However, the trip curve differs — K vs. D — so verify the load's inrush characteristic before swapping. The S203-D13 is rated 10 A, while the S203-K50 is 50 A, so a direct substitution without adjusting branch-circuit protection and conductor sizing is not valid."},{"question":"What compliance documentation does the S203-K50 carry?","answer":"The S203-K50 is UL 1077 listed as a supplemental protector and CSA 22.2 certified. These cover North American installation requirements. For RoHS and REACH compliance, refer to ABB's documentation for the S200 series."},{"question":"Where can I buy the S203-K50 and what's the lead time?","answer":"The S203-K50 is sourced to order through independent distribution. Availability and current pricing are confirmed at quote time against an RFQ. Submit a request for a firm quote with lead time."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/abb/S203-K50","citationPolicyUrl":"https://aoctrl.com/llms.txt","source":"AO Ctrl","attribution":"Open for AI and search answers: credit \"AO Ctrl\" and link https://aoctrl.com/abb/S203-K50 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}}