{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"S203-B40","brand":"ABB","brandSlug":"abb","productSlug":"S203-B40","canonicalUrl":"https://aoctrl.com/abb/S203-B40","factsUrl":"https://aoctrl.com/api/mcp/products/S203-B40","rawCanonicalId":null},"summary":{"shortDescription":"ABB S203-B40, 3-pole miniature circuit breaker, 40 A, Trip Curve B, 277 VAC, 10 kA interrupting rating, DIN-rail mount.","salesMarkdown":"## Branch-circuit protection for three-phase panels The ABB S203-B40 is a 3-pole miniature circuit breaker rated at 40 A with a Trip Curve B characteristic, meaning it trips at 3–5× rated current — suited for resistive loads, lighting circuits, and lightly inductive equipment where inrush is modest. DIN-rail mount snaps into standard 35 mm rail, so it integrates directly into an existing panel without adapter hardware. ## Curve B vs. other trip curves Trip Curve B (3–5× In) is the correct choice when the load draws minimal inrush — think lighting banks, resistive heaters, or general-purpose outlets. If the downstream equipment includes motor starters or transformers with higher magnetizing inrush, a Curve C (5–10× In) or Curve K (10–14× In) breaker would be specified instead. The S203-B40's 40 A frame and 10 kA SCCR at 277 VAC are shared across the S200 series; the curve is the deciding factor for coordination.","metaTitle":"S203-B40 Miniature Circuit Breaker, 3P, 40A, Curve B, 10kA","metaDescription":"ABB S203-B40 miniature circuit breaker, 3-pole, 40 A, Trip Curve B, 277 VAC, 10 kA interrupting rating. DIN-rail mount, current-production status. Sourced to order against RFQ.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["3-Pole MCB (DIN Rail)"],"specifications":{"Amps":"40","Type":"Trip Curve B","Poles":"3","title":"S203-B40","Mounting":"DIN Rail","Volts AC":"277","description":"Miniature Circuit Breaker, 3P, 40A|Miniature Circuit Breaker, 3 Pole, 40 Amp","lifecycle_stage":"current","Interrupt Rating AC":"10 kA"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"stockQuantity":0,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/398c3ec4d6157c214b988bfe7bfb9822.pdf","sourceUrl":null},"ai":{"faq":[{"question":"What is S203-B40's interrupting rating?","answer":"10 kA at 277 VAC, which covers the majority of branch-circuit fault currents in commercial and light industrial panels."},{"question":"Will S203-B40 drop into a panel specified around S204-B32 without rewiring?","answer":"No — the S204-B32 is a 4-pole, 32 A breaker on the same DIN-rail footprint, but the S203-B40 is 3-pole and 40 A. The pole count and current rating differ, so a panel wired for 4-pole 32 A would need circuit changes to accept this 3-pole 40 A unit."},{"question":"Where can I buy S203-B40 and get current pricing?","answer":"Sourced to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for your quantity and target delivery window."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"icboms-matrix-langgraph","citationUrl":"https://aoctrl.com/abb/S203-B40","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-B40 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}}