{"product_id":"live-cz4125b-4-pole-mcb-10ka-b-curve-125a-4p-circuit-breaker","title":"Live CZ4125B 4 Pole MCB 10kA B Curve 125A | 4P Circuit Breaker","description":"\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cspan\u003eThe \u003c\/span\u003e\u003cstrong\u003e\u003cspan\u003eLive CZ4125B 4 Pole MCB\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e is an ultra-high-capacity industrial-grade miniature circuit breaker designed to provide reliable protection for maximum-power three-phase electrical circuits requiring simultaneous switching of all three phases and neutral conductor with resistive loads. Rated at 125 Amps with a B-curve tripping characteristic, this 4-pole breaker safeguards all three phases (L1, L2, L3) and the neutral (N) conductor 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 near main distribution points and transformers. The B-curve characteristic (3-5x In) provides fast response to faults while accommodating the minimal inrush currents typical of ultra-high-power resistive loads. With its robust construction and precision thermo-magnetic release, the CZ4125B ensures complete circuit isolation and equipment protection for the most demanding high-power applications requiring current ratings well above the standard range with enhanced interrupting capacity.\u003c\/span\u003e\u003c\/p\u003e\n\u003ch2\u003e\u003cspan\u003eKey Features of Live CZ4125B 125A 4P MCB\u003c\/span\u003e\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003eComplete 4-Pole Protection:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Simultaneously protects and switches all three phases (L1, L2, L3) and the neutral (N) conductor, ensuring complete circuit isolation during fault conditions and maintenance.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003eUltra-High-Capacity 125A Rating:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Provides protection for applications requiring 125A capacity, well beyond standard MCB ratings.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003eEnhanced 10kA Breaking Capacity:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Powerful fault current interruption for installations with higher 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\u003eB-Curve Characteristic:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Trips instantaneously at 3-5 times rated current (375A to 625A), specifically calibrated for ultra-high-power circuits with minimal inrush.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003eComplete Isolation:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Neutral pole disconnects simultaneously with phases, preventing floating neutral conditions and ensuring safety during maintenance.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003eMaximum Extended Current Range:\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e Ideal for main distribution boards, large industrial heaters, commercial building mains, and heavy-duty resistive loads requiring neutral switching.\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 four 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.\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\u003eCZ\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\u003eCZ4125B\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\u003e4 Pole (4P) - Switches L1, L2, L3 + N\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\u003e125 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\u003eB Curve (3-5 × 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\u003eNeutral Pole Protection\u003c\/span\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eFully protected and switched\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\u003e50-70 mm² (suitable for 125A)\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 large-scale applications require a 125A 4-pole B-Curve MCB with 10kA protection?\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eMain distribution boards for large industrial complexes, commercial high-rises, data center power distribution, hospital main switchboards, and installations with TN-S or IT earthing systems requiring complete isolation.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003e2. What is the power capacity of this 125A 4-pole B-Curve breaker?\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eMaximum resistive load: 86.5kW at 400V three-phase. Continuous load (80% rule): 69kW. Suitable for very large industrial heating applications and main distribution with fast B-Curve response.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003e3. Why choose 125A 4-pole over 100A for large commercial buildings?\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eProvides 25% additional capacity for facilities with high power demands, essential for buildings with large HVAC systems, elevators, and heavy equipment where 100A would be insufficient.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003e4. What earthing systems require 4-pole isolation at 125A capacity?\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003eIT earthing systems (unearthed neutral), TN-C-S to TN-S transition points, generator changeover panels, and installations where complete isolation of all conductors including neutral is mandated by regulations.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp class=\"ds-markdown-paragraph\"\u003e\u003cstrong\u003e\u003cspan\u003e5. What cable size is mandatory for 125A 4-pole circuits?\u003c\/span\u003e\u003c\/strong\u003e\u003cspan\u003e\u003c\/span\u003e\u003cbr\u003e\u003cspan\u003e35mm² copper conductor minimum per phase and neutral. 50mm² strongly recommended for longer runs and higher ambient temperatures. All four conductors (L1, L2, L3, N) must be identical size.\u003c\/span\u003e\u003c\/p\u003e","brand":"LIVE ELECTRIC","offers":[{"title":"Default Title","offer_id":57045036335486,"sku":null,"price":27.06,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0985\/3832\/4350\/files\/CZ4125B.webp?v=1772921113","url":"https:\/\/ssmelectric.co.uk\/products\/live-cz4125b-4-pole-mcb-10ka-b-curve-125a-4p-circuit-breaker","provider":"SSM ELECTRIC","version":"1.0","type":"link"}