WKC 3 Pole 10kA MCB – 40A B Curve (WKC340B)
18th Ed. Compliant
2-Year Warranty
UK Stock
Free Delivery £30+
Secure Payments With
The WKC340B 3 Pole 10kA MCB is a 40A B Curve breaker providing short-circuit and overload protection for three-phase circuits. Built with a 10kA breaking capacity and full compliance with BS 7671 (18th Edition), it’s trusted in industrial boards, EV charging setups, and solar PV systems. Compact, DIN rail mountable,...
The WKC340B 3 Pole 10kA MCB is a 40A B Curve breaker providing short-circuit and overload protection for three-phase circuits. Built with a 10kA breaking capacity and full compliance with BS 7671 (18th Edition), it’s trusted in industrial boards, EV charging setups, and solar PV systems. Compact, DIN rail mountable, and bi-directional, it delivers safe and reliable disconnection in demanding environments.
Installer Tip: Choose the B Curve for resistive loads such as lighting and socket circuits. For inductive or high inrush loads, see the C Curve or D Curve variants.
Key Features
- 40A rated current – suited for heavier three-phase loads
- B Curve tripping – rapid fault clearance for resistive circuits
- 10kA breaking capacity – safe operation under high fault levels
- 3 Pole design: protection across all three phases
- Bi-directional: top or bottom wiring accepted
- Applications: industrial boards, lighting, sockets, EV/PV circuits
Compare 40A 3 Pole Variants
| Model | Curve | Rated Current | Breaking Capacity |
|---|---|---|---|
| WKC340B (This Product) | B Curve | 40A | 10kA |
| WKC340C | C Curve | 40A | 10kA |
| WKC340D | D Curve | 40A | 10kA |
Where should the WKC340B be installed?
It’s ideal for commercial and industrial boards protecting 40A resistive three-phase loads such as lighting and socket circuits.
What’s the difference between B, C, and D Curves?
B Curve trips at 3–5x In (resistive loads). C Curve trips at 5–10x In for inductive loads. D Curve trips at 10–20x In for high inrush equipment.
Why choose a 10kA MCB?
It ensures safe interruption under fault levels up to 10,000A, making it suitable for most commercial and industrial installs.
Is it bi-directional?
Yes — the breaker can be wired from top or bottom.
Is this breaker EV and PV compatible?
Yes — widely used in EV charger protection and solar PV boards.
- Product Code: WKC340B
- Type: Miniature Circuit Breaker (MCB)
- Poles: 3P (three-phase)
- Rated Current: 40A
- Curve: B Curve
- Breaking Capacity: 10kA
- Mounting: DIN rail, 18mm per module
- Functions: Overload & short-circuit protection, switching, isolation
- Compliance: BS 7671 (18th Edition)
- Endurance: 4000 mechanical / 2000 electrical operations
- Brand: WCED
Mount on a DIN rail inside consumer units or distribution boards. Select curve based on application:
- B Curve: resistive circuits such as lighting or sockets
- C Curve: inductive circuits (motors, HVAC, EV chargers)
- D Curve: heavy inrush loads (transformers, welders)
Verify that the installation’s fault level is within the 10kA capacity. All installations must follow BS 7671 and be carried out by a qualified electrician.
