4 Pole RCBO – 40A B Curve, Type A, 30mA (WCED WFR440B-030)
18th Ed. Compliant
2-Year Warranty
UK Stock
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The WCED WFR440B-030 is a 40A, B Curve, 4 Pole Type A RCBO that delivers comprehensive protection for higher-capacity circuits. It combines MCB overcurrent protection with RCD earth leakage detection in one device, ensuring both live and neutral conductors are fully isolated through the switched neutral mechanism. Designed for robust...
The WCED WFR440B-030 is a 40A, B Curve, 4 Pole Type A RCBO that delivers comprehensive protection for higher-capacity circuits. It combines MCB overcurrent protection with RCD earth leakage detection in one device, ensuring both live and neutral conductors are fully isolated through the switched neutral mechanism. Designed for robust domestic, commercial, and renewable applications, it is fully compliant with BS 7671 (18th Edition).
This RCBO is suited for circuits with steady resistive or lightly inductive loads, such as larger heating systems, lighting arrays, or commercial socket banks. With high immunity electronics and bidirectional design, it also supports EV charging, solar PV, and inverter-driven systems.
Installer Tip: Use the B Curve 40A for high-capacity but steady load circuits. If you expect high inrush currents (e.g. EV chargers, motors, or solar inverters), choose the C Curve version instead.
Key Features
- 40A, B Curve: Fast tripping for steady resistive loads
- 4 Pole Isolation: Disconnects all conductors including neutral
- Type A RCD: Detects AC and pulsating DC leakage
- Switched Neutral: Safer testing & full isolation
- High Immunity: Stable under electronic and inverter loads
- Bidirectional: Renewable & EV-ready
- Compact Build: Single-module DIN rail mount (17.8mm)
- Standards: BS EN 61009-1, BS 7671 (18th Edition)
Other Variants in the WFR4 Series
| Model | Rating | Curve | Link |
|---|---|---|---|
| WFR406B-030 | 6A | B | View Product |
| WFR406C-030 | 6A | C | View Product |
| WFR410B-030 | 10A | B | View Product |
| WFR410C-030 | 10A | C | View Product |
| WFR416B-030 | 16A | B | View Product |
| WFR416C-030 | 16A | C | View Product |
| WFR420B-030 | 20A | B | View Product |
| WFR420C-030 | 20A | C | View Product |
| WFR432B-030 | 32A | B | View Product |
| WFR432C-030 | 32A | C | View Product |
| WFR440B-030 (This Product) | 40A | B | – |
| WFR440C-030 | 40A | C | View Product |
What applications suit the WFR440B-030?
It’s ideal for 40A circuits with steady load demand such as heating systems, lighting banks, and large commercial socket runs.
What’s the difference between B Curve and C Curve?
B Curve trips faster for resistive or light inductive loads. C Curve allows for higher inrush currents such as motors, EV chargers, and solar inverters.
Does this RCBO provide full isolation?
Yes – the switched neutral ensures all live conductors and neutral are isolated during a fault or test.
Is it compliant with UK regulations?
Yes – fully compliant with BS EN 61009-1 and BS 7671 (18th Edition Wiring Regulations).
Is it suitable for EV and solar installs?
Yes – high immunity and bidirectional design make it suitable for EV charging, solar PV, and renewable circuits.
- SKU: WFR440B-030
- Device Type: 4 Pole Type A RCBO
- Current Rating: 40A
- Curve: B
- Residual Current: 30mA, high immunity
- Poles: 4 (with switched neutral)
- Isolation: Disconnects all live & neutral conductors
- Dimensions (HxWxD): 67.6 × 71.6 × 67.5mm
- Mounting: 35mm DIN rail
- Compliance: BS EN 61009-1, BS 7671:2018 (Amendment 2)
Install in line with BS 7671 (18th Edition). Always match RCBO curve and rating to circuit design.
- B Curve: Use for stable load circuits (heating banks, large lighting runs, fixed socket circuits)
- Mounting: Fits 35mm DIN rail
- Testing: Switched neutral allows safe insulation resistance tests
- Application: Suitable for high-capacity domestic, commercial, and renewable installs
