4 Way Metal Enclosure – 40A B Curve MCB + Surge Protection (WMKB240BSP)
18th Ed. Compliant
2-Year Warranty
UK Stock
Free Delivery £30+
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The WMKB240BSP is a compact 4 way metal enclosure pre-fitted with a 40A B Curve MCB and Type 2 Surge Protection Device (SPD). Built for EV charger supplies, outbuildings, and small sub-mains, it combines overload protection and surge defence in a durable steel housing. The 40A B Curve MCB makes...
The WMKB240BSP is a compact 4 way metal enclosure pre-fitted with a 40A B Curve MCB and Type 2 Surge Protection Device (SPD). Built for EV charger supplies, outbuildings, and small sub-mains, it combines overload protection and surge defence in a durable steel housing.
The 40A B Curve MCB makes this unit suitable for domestic EV installs, general distribution boards, and standard load circuits. With a pre-fitted Type 2 SPD, it ensures compliance with 18th Edition Amendment 2 and gives added resilience against transient overvoltages.
Installer Tip: Use the B Curve model for standard domestic circuits. If you expect higher inrush currents (motors, heat pumps, certain EV chargers), opt for the C Curve variant.
Key Features
- 40A B Curve MCB – protection against overloads and short-circuits
- Factory-fitted Type 2 SPD – compliance with 18th Edition surge protection requirements
- 4 way steel enclosure – robust, compact, and durable
- Supplied fully built – saves installation time
- Complies with BS EN 61439-3
Compare 4 Way MCB + SPD Enclosure Variants
| Model | Rating | Curve | Protection |
|---|---|---|---|
| WMKB240BSP (This Product) | 40A | B | MCB + SPD |
| WMKB240CSP | 40A | C | MCB + SPD |
Is this enclosure suitable for EV charger installs?
Yes. It is built for EV-ready supplies requiring a 40A breaker and Type 2 SPD. For other sizes, view our EV consumer unit range.
When should I use B Curve vs C Curve?
B Curve MCBs suit domestic/general loads, while C Curve options handle higher inrush currents (e.g. motors, certain EV chargers). Choose based on your application.
Does this unit include earth leakage protection?
No. It includes an MCB + SPD. If RCD protection is required, pair with an upstream RCBO or specify an RCBO version.
How quickly is this supplied?
As it’s built to order, allow 3 working days for assembly. Once dispatched, next-day delivery applies.
- Enclosure: 4 way steel housing, IP40
- MCB: 40A, 2 module, B Curve
- Surge Protection: Type 2 SPD, factory fitted
- Operating Voltage: 230V AC, 50Hz
- Standards: BS EN 61439-3
- Build Time: 3 working days
This unit is supplied pre-built with MCB and SPD installed. A qualified electrician must complete final wiring and testing.
- Fully assembled – no internal wiring required
- Knockouts provided for flexible cable entry
- Confirm breaker curve (B or C) matches load type
- Install in a dry, accessible location with adequate ventilation
