{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"S203-Z20","brand":"ABB","brandSlug":"abb","productSlug":"S203-Z20","canonicalUrl":"https://aoctrl.com/abb/S203-Z20","factsUrl":"https://aoctrl.com/api/mcp/products/S203-Z20","rawCanonicalId":null},"summary":{"shortDescription":"ABB S203-Z20, 3-pole miniature circuit breaker, 20 A, Trip Curve Z, 277 V AC, 10 kA interrupting capacity, DIN rail mount.","salesMarkdown":"## Rated current and trip characteristic This makes it the right choice for protecting semiconductor circuits, control transformers, or sensitive electronic loads where a standard MCB might nuisance-trip on inrush. ## Interrupting capacity and voltage rating Rated at 10 kA interrupting capacity at 277 V AC per pole. The 277 V AC rating covers line-to-neutral on a 480Y/277 V wye system, which is the common commercial lighting and small-power distribution voltage in North America. The 3-pole housing occupies three modular units (17.5 mm per pole) — 52.5 mm of rail space. No mounting screws needed; clip it on, torque the line and load terminals to the recommended value (typically 2.5 N·m for the cage clamp), and it's locked in. Leave a finger's width of air gap between adjacent breakers if you're running near the 20 A continuous rating — thermal derating in a tightly packed row can reduce the effective trip point.","metaTitle":"ABB S203-Z20 MCB, 3P, 20A, Curve Z, 10 kA","metaDescription":"ABB S203-Z20 miniature circuit breaker, 3-pole, 20 A, Trip Curve Z, 277 V AC, 10 kA interrupting capacity. DIN rail mount. Current lifecycle stage. Available to order.","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Miniature Circuit Breakers (MCB)"],"specifications":{"Amps":"20","Type":"Trip Curve Z","Poles":"3","Mounting":"DIN Rail","Volts AC":"277","lifecycle_stage":"current","Interrupt Rating AC":"10 kA"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":"https://cdn.aoctrl.com/5ebb4469d65988b81450a314e79763ad.pdf","sourceUrl":null,"alternativesUrl":"https://aoctrl.com/api/mcp/products/S203-Z20/alternatives.json"},"ai":{"faq":[{"question":"What is the interrupting rating of the S203-Z20?","answer":"10 kA at 277 V AC. That's the maximum fault current the breaker can safely interrupt under short-circuit conditions. Verify that your available fault current at the panel does not exceed this value."},{"question":"Where can I buy the S203-Z20?","answer":"Sourced and quoted to order against an RFQ through independent distribution. Availability and current pricing are confirmed at quote time."},{"question":"What does Trip Curve Z mean for this breaker?","answer":"The Z curve has a magnetic trip threshold of 2 to 3 times the rated current (40–60 A for this 20 A breaker). It's designed for semiconductor protection and sensitive electronic loads where a B or C curve would nuisance-trip on small inrush or transient currents."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/abb/S203-Z20","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-Z20 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}}