40A 2 Pole 10kA MCB – B Curve (WKC240B)
18th Ed. Compliant
2-Year Warranty
UK Stock
Free Delivery £30+
Secure Payments With
The WKC240B is a 40A 2 Pole 10kA Miniature Circuit Breaker (MCB) designed to protect higher-load radial and feeder circuits against short-circuit and overload faults. The B-curve tripping profile ensures rapid disconnection for resistive and low-inrush circuits such as outbuilding sub-mains, immersion heaters, and EV control feeds. With dual-pole isolation,...
The WKC240B is a 40A 2 Pole 10kA Miniature Circuit Breaker (MCB) designed to protect higher-load radial and feeder circuits against short-circuit and overload faults. The B-curve tripping profile ensures rapid disconnection for resistive and low-inrush circuits such as outbuilding sub-mains, immersion heaters, and EV control feeds.
With dual-pole isolation, both live conductors are disconnected simultaneously to enhance safety and regulatory compliance under BS EN 60898-1. The compact 36 mm housing allows easy DIN-rail mounting within consumer units or three-phase boards.
Installer Tip: Use a 40A B-curve MCB for small sub-main feeds or high-current resistive circuits. For equipment with heavier startup current – such as large pumps or compressors – consider the C-curve or D-curve alternative.
Key Features
- 40 A rated – ideal for outbuilding supplies, EV control circuits, and immersion heaters
- 10 kA breaking capacity – built to withstand high fault levels
- 2-pole isolation – disconnects both live conductors simultaneously
- B-curve tripping – fast operation for resistive or low inrush circuits
- Bi-directional terminals – supply and load can be wired either end
- 36 mm (2-module) width – fits any standard 35 mm DIN rail
- BS EN 60898-1 compliant – 18th Edition regulation ready
- Compatible with EV consumer units and metal enclosures
Compare 2 Pole 10 kA MCB Variants
| Model | Rating | Curve |
|---|---|---|
| WKC240B | 40 A | B Curve (This Product) |
| WKC240C | 40 A | C Curve |
| WKC240D | 40 A | D Curve |
What’s the typical use for a 40 A B-curve MCB?
Commonly used for small sub-mains, outbuilding supplies, and fixed heating or EV control circuits with low inrush current.
Does it isolate both live lines?
Yes – the 2-pole design disconnects both conductors simultaneously for safe maintenance.
Is it suitable for EV boards?
Yes – it’s ideal for EV consumer unit sub-feeds or control circuits. See our full EV-ready range.
Is this compliant with BS EN 60898-1?
Yes – fully certified to BS EN 60898-1 and compliant with 18th Edition Amendment 2 wiring standards.
- Model: WKC240B
- Poles: 2
- Rated Current: 40 A
- Curve Type: B
- Breaking Capacity: 10 kA
- Operating Voltage: 230/400 V AC
- Mounting: 35 mm DIN rail (EN 60715)
- Width: 36 mm (2 modules)
- Standard: IEC/EN 60898-1
- Applications: Outbuilding feeds, EV control, immersion, small sub-mains
To be installed by a qualified electrician in accordance with BS 7671. Confirm circuit rating, curve type, and cable sizing before energising.
- Mount securely on 35 mm DIN rail (EN 60715)
- Tighten terminal screws to 2.0–2.5 Nm torque
- Check polarity and insulation resistance before connection
- Clearly label protected circuit in the distribution schedule
