3 Pole MCBs for Three-Phase Circuit Protection
3 pole MCBs provide overcurrent and short-circuit protection across all three live phases of a three-phase supply. They are used in commercial boards, industrial panels, machinery circuits and distribution systems where all phases must disconnect together during a fault.
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Designed for three-phase loads, these breakers ensure simultaneous isolation of L1, L2 and L3, preventing phase imbalance and equipment damage. They are available in a wide range of current ratings and tripping curves to support motors, pumps, compressors, HVAC systems, heating equipment and plant machinery.
- Three-phase protection for balanced and unbalanced loads
- Simultaneous tripping across all three phases
- B and C curve options for different startup behaviours
- High breaking capacities for industrial fault levels
- DIN-rail compatible modules for commercial and industrial boards
3 Pole MCBs are essential wherever three-phase equipment is used and are a standard requirement in workshops, factories, plant rooms and commercial buildings.
WKC 3 Pole 10kA MCB – 50A C Curve (WKC350C)
£21.30
The WKC350C 3 Pole 10kA MCB is a 50A C Curve miniature circuit breaker designed to protect three-phase circuits from overloads and short-circuits. With a 10kA breaking capacity and full compliance with BS 7671 (18th Edition), it’s a dependable choice for medium-to-heavy inductive loads including...
WKC 3 Pole 10kA MCB – 50A B Curve (WKC350B)
£21.30
The WKC350B 3 Pole 10kA MCB is a 50A B Curve breaker providing reliable short-circuit and overload protection for three-phase circuits. Rated at 10kA breaking capacity and compliant with BS 7671 (18th Edition), it’s a trusted solution for industrial boards, EV installations, and solar PV...
WKC 3 Pole 10kA MCB – 40A C Curve (WKC340C)
£21.30
The WKC340C 3 Pole 10kA MCB is a 40A C Curve breaker built for protecting three-phase circuits with moderate inrush currents. Rated at 10kA breaking capacity, it provides safe disconnection during overload and short-circuit faults. Compact, bi-directional, and DIN rail mounted, it’s a reliable choice...
WKC 3 Pole 10kA MCB – 20A C Curve (WKC320C)
£21.30
The WKC320C 3 Pole 10kA MCB is a 20A C Curve breaker built to safeguard three-phase circuits against overload and short-circuit faults. With a 10kA breaking capacity and full compliance with BS 7671 (18th Edition), it’s ideal for circuits with moderate inrush currents such as...
WKC 3 Pole 10kA MCB – 20A B Curve (WKC320B)
£21.30
The WKC320B 3 Pole 10kA MCB is a 20A B Curve breaker designed to protect three-phase circuits against overloads and short circuits. With a 10kA breaking capacity and compliance to BS 7671 (18th Edition), it’s a trusted choice for industrial boards, EV charger setups, and...
What Is a 3 Pole MCB?
A 3 pole MCB disconnects all three live conductors at the same time when an overcurrent or short-circuit occurs. This protects three-phase motors and equipment from imbalance damage and ensures safe isolation of the entire circuit.
Where 3 Pole MCBs Are Used
- Three-phase distribution boards in commercial and industrial buildings
- Motors, pumps and compressors with significant startup demands
- HVAC and ventilation systems requiring stable three-phase supply
- Machinery circuits in workshops, factories and processing plants
- Heaters, welders and plant equipment with fluctuating load profiles
B Curve vs C Curve 3 Pole MCBs
B Curve: Trips at 3–5 × rated current; suitable for light-duty three-phase loads and predictable startup current.
C Curve: Trips at 5–10 × rated current; ideal for motor-driven loads, compressors, pumps and equipment with noticeable inrush.
Benefits of 3 Pole Protection
Three-phase equipment can suffer serious mechanical and electrical damage if only one or two phases disconnect. A 3 pole MCB avoids this by tripping all phases together, ensuring full isolation and preventing phase-loss faults.
- Balanced disconnection prevents equipment strain and overheating
- Reliable performance under heavy or surge-prone loads
- Correct coordination with motor and machinery characteristics
Compliance & Standards
All 3 Pole MCBs in this category comply with BS EN 60898 and meet the requirements of the 18th Edition Wiring Regulations. They are suitable for new installations, commercial upgrades and equipment protection in three-phase environments.
Installer Benefits
3 Pole MCBs give electricians dependable protection for industrial and commercial systems. Their robust construction, predictable tripping characteristics and wide rating options make them ideal for plant equipment, three-phase motors and multi-phase distribution boards.