{"product_id":"live-cb320d-triple-pole-mcb-10ka-d-curve-20a-3p-circuit-breaker","title":"Live CB320D Triple Pole MCB 10kA D Curve 20A | 3P Circuit Breaker","description":"\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cspan\u003eThe \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eLive CB320D Triple Pole MCB\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e is a specialized high-performance industrial-grade miniature circuit breaker engineered to provide reliable protection for three-phase electrical circuits with extremely high inrush currents. Rated at 20 Amps with a D-curve tripping characteristic, this 3-pole breaker safeguards all three phases (L1, L2, L3) on AC systems up to 400V at 50\/60Hz frequency. It features a powerful \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003e10kA breaking capacity\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e, making it suitable for installations with higher prospective short-circuit currents. The D-curve characteristic (10-20x In) is specifically designed for applications with very high momentary startup currents, ensuring the breaker tolerates these extreme surges while maintaining full protection against overloads and short circuits. With its robust construction and precision thermo-magnetic release, the CB320D ensures equipment protection and operational safety for specialized industrial applications requiring three-phase protection with extreme surge tolerance.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch2\u003e\u003cspan\u003eKey Features of Live CB320D 20A 3P MCB\u003c\/span\u003e\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003eTriple Pole Protection:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Simultaneously protects all three phases (L1, L2, L3) in three-phase systems, ensuring complete circuit isolation during fault conditions.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003eHigh 10kA Breaking Capacity:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Powerful fault current interruption for installations with high prospective short-circuit currents up to 10,000 amps.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003eD-Curve Characteristic:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Trips instantaneously at 10-20 times rated current (200A to 400A), specifically engineered for applications with extremely high inrush currents.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003eHigh-Capacity 20A Three-Phase Protection with Extreme Surge Tolerance:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Ideal for three-phase power transformers, large welding equipment, industrial solenoid banks, and heavy machinery with very high startup currents.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003eSpecialized Application Focus:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Prevents nuisance tripping where standard B\/C curves would fail due to extreme inrush at medium-high current ratings.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003ePrecision Thermo-Magnetic Release:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Thermal bimetal strip for accurate overload protection and magnetic solenoid for instantaneous short-circuit response on all three poles.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003eSuperior Electrical Isolation:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e 4000V impulse withstand rating and 500V insulation voltage for protection against voltage transients.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003eExtended Operational Life:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e 8,000 electrical operations for long-term reliability.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003eProfessional Installation:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Standard 35mm DIN-rail mounting with IP20 finger-safe terminals and 16mm² wiring capacity.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003e\u003cspan\u003eTechnical Specifications\u003c\/span\u003e\u003c\/h2\u003e\n\u003cdiv class=\"ds-scroll-area _1210dd7 c03cafe9\"\u003e\n\u003cdiv class=\"ds-scroll-area__gutters\"\u003e\n\u003cdiv class=\"ds-scroll-area__horizontal-gutter\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"ds-scroll-area__vertical-gutter\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003c\/div\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cspan\u003eSpecification\u003c\/span\u003e\u003c\/th\u003e\n\u003cth\u003e\u003cspan\u003eDetails\u003c\/span\u003e\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eBrand\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eLive\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eSeries\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eCB\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eModel Number\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eCB320D\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eDevice Type\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eMiniature Circuit Breaker (MCB)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003ePole Configuration\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e3 Pole (3P)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eCurrent Rating (In)\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e20 Amperes\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eTrip Curve Type\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eD Curve (10-20 × In)\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eOperational Voltage\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e230\/400V AC\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eRated Breaking Capacity\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003e10kA (10000 Amps)\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eFrequency Range\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e50\/60 Hertz\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eInsulation Rating (Ui)\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e500 Volts\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eImpulse Withstand (Uimp)\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e4000 Volts (1.2\/50 µs)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eDielectric Test Voltage\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e2kV for 60 seconds\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eProtection Mechanism\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eThermo-magnetic (all poles)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eOperating Temperature\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e-5°C to +40°C (daily average ≤35°C)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eCalibration Reference\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e30°C\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eStorage Temperature\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e-25°C to +70°C\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eElectrical Lifespan\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e8,000 cycles\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eProtection Class\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eIP20\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eTerminal Capacity\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eUp to 16 mm²\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eMounting Type\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eDIN Rail (35mm)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003e\u003cspan\u003eStandards\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eBS IEC\/EN 60898\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003ch2\u003e\u003cspan\u003eFrequently Asked Questions (FAQs)\u003c\/span\u003e\u003c\/h2\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003e1. What specific applications require a 20A D-Curve triple pole MCB?\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eThree-phase isolation transformers (up to 9kVA), industrial welding equipment, large solenoid banks, X-ray machines, and circuits where extremely high inrush currents occur at medium-high running currents.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003e2. Why choose D-Curve over C-Curve for 20A three-phase transformer protection?\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eD-Curve (10-20x In) handles inrush currents up to 400A where C-Curve (5-10x In) would trip at 200A, making D-Curve essential for larger transformers with high magnetizing inrush during energization.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003e3. What transformer size can this 20A D-Curve breaker support?\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eSuitable for three-phase isolation transformers up to 9kVA, depending on inrush characteristics. The D-Curve tolerates the high magnetizing inrush during transformer energization without nuisance tripping.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003e4. What is the power capacity of this 20A three-phase D-Curve breaker?\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eMaximum resistive load: 13.86kW at 400V three-phase. For inductive applications, suitable for transformer and welding equipment loads within the 20A running current limit.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003e5. What cable size is recommended for 20A D-Curve three-phase circuits?\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e2.5mm² copper conductor minimum per phase. 4mm² recommended for mechanical robustness and longer runs. All three phase conductors must be same size. Terminals accept up to 16mm².\u003c\/span\u003e\u003c\/p\u003e","brand":"LIVE ELECTRIC","offers":[{"title":"Default Title","offer_id":57040118874494,"sku":null,"price":8.14,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0985\/3832\/4350\/files\/CB320C_a53bd2a6-06f8-46d7-89ea-63b87b2f1428.webp?v=1772829010","url":"https:\/\/ssmelectric.co.uk\/products\/live-cb320d-triple-pole-mcb-10ka-d-curve-20a-3p-circuit-breaker","provider":"SSM ELECTRIC","version":"1.0","type":"link"}