6kA MCB – 50A 1 Pole B Curve (WMC150B)
£1.84
£2.99
18th Ed. Compliant
2-Year Warranty
UK Stock
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The WMC150B is a 50 A single-pole 6 kA Miniature Circuit Breaker (MCB) providing dependable overcurrent and short-circuit protection for heavy-duty feed circuits and fixed equipment. Its B-curve tripping characteristic (3–5 × In) ensures rapid disconnection on faults while maintaining stable operation on steady loads. Built to BS EN 60898...
The WMC150B is a 50 A single-pole 6 kA Miniature Circuit Breaker (MCB) providing dependable overcurrent and short-circuit protection for heavy-duty feed circuits and fixed equipment. Its B-curve tripping characteristic (3–5 × In) ensures rapid disconnection on faults while maintaining stable operation on steady loads.
Built to BS EN 60898 standards and compatible with Whitecliffe consumer units, the WMC150B offers a 6 kA breaking capacity and long mechanical life of 20 000 operations. Ideal for feed circuits, plant equipment, or sub-boards in domestic and light-commercial settings.
Installer Tip: Use 50 A B-curve MCBs for feed circuits and heavy fixed loads drawing up to around 11.5 kW at 230 V. Check voltage drop, cable capacity and protective coordination against upstream devices for BS 7671 compliance.
- 50 A rated current with B-curve (3–5 × In) tripping profile
- 6 kA breaking capacity at 230/400 V AC
- Single-pole design – 18 mm module width
- DIN-rail mounted for consumer units and distribution boards
- Complies with BS EN 60898 and BS 7671 (18th Edition A2)
- Tested service life – 20 000 mechanical / 8 000 electrical operations
- Front contact indicator for quick status check
| Part Code | Rating | Curve | Typical Use |
|---|---|---|---|
| WMC140B | 40 A | B | Sub-mains and high-load circuits |
| WMC150B | 50 A | B | Feed circuits and plant equipment |
| WMC163B | 63 A | B | Large distribution feeds and industrial loads |
| WMC150C | 50 A | C | Motors or transformer loads with high inrush |
The WMC150B offers dependable 6 kA fault protection for feed and plant circuits. For motor or transformer loads requiring higher inrush tolerance, see our C Curve MCB range or upgrade to Type A RCBOs for combined overcurrent and earth-fault protection.
Where is a 50 A B Curve MCB used?
Commonly on feed circuits, plant equipment or sub-boards where loads are steady and inrush currents are low. It trips quickly at 3–5 × In to protect cables and equipment.
Is the WMC150B compatible with Whitecliffe boards?
Yes – it fits all Whitecliffe consumer units and standard 18 mm DIN-rail enclosures.
Can this breaker be used for a plant feed or distribution board?
Yes, provided the cable and enclosure are rated appropriately for the load and environment. For outdoor use, choose an IP65 plastic enclosure.
When should I choose a C Curve MCB instead?
Use a C Curve MCB for motors, compressors or transformer loads that draw high inrush current during startup.
What does 6 kA mean?
6 kA is the maximum fault current the breaker can safely interrupt without damage. For sites with higher prospective fault levels, see our 10 kA MCB range.
- Part Code: WMC150B
- Type: Single Pole MCB
- Rated Current (In): 50 A
- Curve: B (3–5 × In tripping characteristic)
- Rated Voltage (Ue): 230/400 V AC
- Rated Frequency: 50/60 Hz
- Breaking Capacity (Icn): 6 kA
- Insulation Voltage (Ui): 500 V
- Impulse Withstand (Uimp): 4 kV
- Dielectric Test Voltage: 2 kV for 1 minute
- Thermal Reference Temp: 30 °C
- Operating Temperature: –5 °C to +40 °C (avg < 35 °C)
- Mechanical Life: 20 000 operations
- Electrical Life: 8 000 operations
- Mounting: 35 mm DIN rail (1 module width)
- Standards: BS EN 60898; BS 7671:2018 (Amendment 2)
- Typical Applications: Feed circuits, plant equipment, and sub-board supplies in domestic or light-commercial installations
Fit the WMC150B in a suitable consumer unit or distribution board by a qualified electrician. Confirm the MCB rating and curve type match the circuit design and upstream protection.
- Mount securely on 35 mm DIN rail and check busbar alignment
- Use B-curve for steady feed and fixed load circuits
- Confirm cable sizing and Zs meet BS 7671 requirements
- Use C-curve for motors or high inrush loads
- Torque terminals to manufacturer spec and record test results
