4 Pole MCBs for Three-Phase + Neutral Circuit Protection
4 pole MCBs provide simultaneous overcurrent and short-circuit protection across all three live phases and the neutral conductor. They are used on distribution circuits, plant equipment, large machinery feeds and systems where neutral disconnection is required for safety and compliance.
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These devices ensure that L1, L2, L3 and N all disconnect together during a fault, preventing dangerous phase imbalance, neutral back-feed or incomplete isolation. This makes 4 pole MCBs essential for sub-mains, industrial distribution panels, changeover arrangements and any installation with critical neutral-related safety considerations.
- Simultaneous disconnection of all three phases + neutral
- B and C curve options for different load and inrush conditions
- Ideal for three-phase distribution boards with neutral isolation
- High breaking capacities for commercial and industrial fault levels
- DIN-rail mounting for simple integration into multi-module systems
4 pole MCBs are widely used in large commercial buildings, plant rooms, workshops, industrial machinery circuits, and anywhere neutral disconnection is required for safety, maintenance or equipment protection.
40A 4 Pole 10kA MCB C Curve – WKC440C
£14.16
The WKC440C is a 40A 4 pole 10kA Miniature Circuit Breaker (MCB) designed for three-phase + neutral protection. With its C Curve trip profile, it is built for inductive load circuits such as motors, pumps, HVAC systems, EV chargers, and commercial lighting in three-phase boards,...
40A 4 Pole 10kA MCB B Curve – WKC440B
£14.16
The WKC440B is a 40A 4 pole 10kA Miniature Circuit Breaker (MCB) for three-phase + neutral circuits. With its B Curve trip characteristic, this breaker is intended for resistive load circuits such as socket outlet banks, small distribution boards, and lighting groups in commercial three-phase...
4 Pole MCB 10kA C Curve 100A WKC4100C
£30.67
The WCED WKC4100C is a 4 Pole 100A MCB with a C curve tripping characteristic and a 10kA breaking capacity. Designed for high-demand installations, it provides reliable protection against overloads and short-circuits while also serving as an isolator when required. Commonly used in EV charging...
4 pole 10kA MCB's 10A B Curve WKC410B
£14.16
The WKC410B is a 10A 4 pole 10kA Miniature Circuit Breaker (MCB) designed for three-phase + neutral circuits. With a B Curve trip characteristic, it is suited for resistive loads such as lighting and socket circuits across three-phase distribution boards, EV installations, and solar PV...
32A 4 Pole 10kA MCB D Curve – WKC432D
£14.16
The WKC432D is a 32A 4 pole 10kA Miniature Circuit Breaker (MCB) built for three-phase + neutral protection. With a D Curve trip profile, it is designed for very high inrush load circuits such as welders, transformers, heavy-duty motors, compressors, and industrial machinery. It is...
What Is a 4 Pole MCB?
A 4 pole MCB is a miniature circuit breaker that simultaneously disconnects L1, L2, L3 and the neutral conductor when a fault occurs. This ensures full isolation of the entire supply, eliminating neutral-related risks and ensuring safe maintenance and operation.
Where 4 Pole MCBs Are Used
- Three-phase distribution circuits requiring neutral isolation
- Industrial machinery with balanced or unbalanced three-phase loads
- Pumps, compressors and HVAC systems with sensitive equipment
- Sub-mains to secondary boards in factories and commercial buildings
- Switchgear, control panels and plant equipment containing mixed-phase electronics
B Curve vs C Curve 4 Pole MCBs
B Curve: Trips at 3–5 × rated current. Suitable for steady loads with low inrush.
C Curve: Trips at 5–10 × rated current. Preferred for motors, drives and equipment with higher startup demand.
Why Use a 4 Pole Device?
Standard 3 pole breakers disconnect only the three live conductors. A 4 pole MCB adds neutral disconnection, which is vital when:
- Neutral integrity is critical (TT or mixed systems)
- The load contains electronics that can be damaged by partial isolation
- Preventing back-feed from downstream circuits is essential
- Safe maintenance requires full, guaranteed isolation
Compliance & Standards
All 4 Pole MCBs in this category comply with BS EN 60898 and meet the requirements of the 18th Edition Wiring Regulations for multi-phase protection and overcurrent coordination.
Installer Benefits
4 Pole MCBs offer safe, reliable and predictable protection for complex three-phase systems. Their combined phase-neutral isolation helps prevent equipment damage, supports safer maintenance procedures and ensures compliance on circuits where neutral switching is mandatory.