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Live CB350B Triple Pole MCB 10kA B Curve 50A | 3P Circuit Breaker

Live CB350B Triple Pole MCB 10kA B Curve 50A | 3P Circuit Breaker

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AvailabilityLow stock: 98 left

Vendor: LIVE ELECTRIC
Category: Circuit Breaker

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Installation & Safety

Installation must be carried out by a qualified electrician.
Ensure power is switched off before installation.
Suitable for indoor use.

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The Live CB350B Triple Pole MCB is a high-capacity industrial-grade miniature circuit breaker designed to provide reliable protection for very high-power three-phase electrical circuits with resistive loads. Rated at 50 Amps with a B-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 10kA breaking capacity, making it suitable for installations with higher prospective short-circuit currents. The B-curve characteristic (3-5x In) provides fast response to faults while accommodating the minimal inrush currents typical of very high-power industrial and commercial resistive loads. With its robust construction and precision thermo-magnetic release, the CB350B ensures equipment protection and operational safety for demanding industrial and commercial applications requiring three-phase protection at very high current ratings.

Key Features of Live CB350B 50A 3P MCB

  • Triple Pole Protection: Simultaneously protects all three phases (L1, L2, L3) in three-phase systems, ensuring complete circuit isolation during fault conditions.

  • High 10kA Breaking Capacity: Powerful fault current interruption for installations with high prospective short-circuit currents up to 10,000 amps.

  • B-Curve Characteristic: Trips instantaneously at 3-5 times rated current (150A to 250A), specifically calibrated for very high-power circuits with minimal inrush.

  • Very High-Capacity 50A Three-Phase Protection: Ideal for large industrial heaters (up to 34kW), main distribution boards, high-power commercial facilities, and large-scale resistive loads.

  • Wide Application Range: Suitable for heavy industrial facilities, large commercial buildings, and main distribution applications requiring high-current resistive load protection.

  • Precision Thermo-Magnetic Release: Thermal bimetal strip for accurate overload protection and magnetic solenoid for instantaneous short-circuit response on all three poles.

  • Superior Electrical Isolation: 4000V impulse withstand rating and 500V insulation voltage for protection against voltage transients.

  • Extended Operational Life: 8,000 electrical operations for long-term reliability.

  • Professional Installation: Standard 35mm DIN-rail mounting with IP20 finger-safe terminals and 16mm² wiring capacity.

Technical Specifications



Specification Details
Brand Live
Series CB
Model Number CB350B
Device Type Miniature Circuit Breaker (MCB)
Pole Configuration 3 Pole (3P)
Current Rating (In) 50 Amperes
Trip Curve Type B Curve (3-5 × In)
Operational Voltage 230/400V AC
Rated Breaking Capacity 10kA (10000 Amps)
Frequency Range 50/60 Hertz
Insulation Rating (Ui) 500 Volts
Impulse Withstand (Uimp) 4000 Volts (1.2/50 µs)
Dielectric Test Voltage 2kV for 60 seconds
Protection Mechanism Thermo-magnetic (all poles)
Operating Temperature -5°C to +40°C (daily average ≤35°C)
Calibration Reference 30°C
Storage Temperature -25°C to +70°C
Electrical Lifespan 8,000 cycles
Protection Class IP20
Terminal Capacity Up to 16 mm²
Mounting Type DIN Rail (35mm)
Standards BS IEC/EN 60898

Frequently Asked Questions (FAQs)

1. What specific applications require a 50A triple pole MCB with B-Curve?
Large industrial duct heaters (up to 34kW), main distribution boards for industrial facilities, high-power commercial building mains, large-scale resistive heating systems, and heavy-duty catering facilities.

2. What is the power capacity of this 50A three-phase breaker?
Maximum resistive load: 34.64kW at 400V three-phase. Per phase capacity: 11.5kW at 230V. Suitable for large industrial heating applications and main distribution.

3. Can this breaker be used as a main switch for an industrial facility?
Yes, it's ideal as a main isolation breaker for small to medium industrial facilities, providing protection for multiple high-power resistive loads with fast B-Curve response.

4. Why choose 10kA breaking capacity for 50A industrial main distribution?
Provides essential protection in installations with high fault currents, such as near main transformers in industrial settings where fault levels may approach 10kA.

5. What cable size is mandatory for 50A three-phase circuits?
10mm² copper conductor minimum per phase. 16mm² strongly recommended for longer runs or higher ambient temperatures. All three phase conductors must be same size. Terminals accept up to 16mm².