4 Pole RCBO – 20A B Curve, Type A, 30mA (WCED WFR420B-030)
18th Ed. Compliant
2-Year Warranty
UK Stock
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The WCED WFR420B-030 is a 20A, B Curve, 4 Pole Type A RCBO that provides combined protection against overcurrent, earth leakage, and arc faults. Its switched neutral design guarantees full isolation of all conductors, making it safer for testing, fault finding, and ongoing compliance with BS 7671 (18th Edition). Rated...
The WCED WFR420B-030 is a 20A, B Curve, 4 Pole Type A RCBO that provides combined protection against overcurrent, earth leakage, and arc faults. Its switched neutral design guarantees full isolation of all conductors, making it safer for testing, fault finding, and ongoing compliance with BS 7671 (18th Edition).
Rated at 20A, this RCBO is suited to circuits carrying moderate loads in domestic, commercial, and renewable applications. The B Curve trip ensures fast disconnection for resistive or small inductive circuits, while the device’s high immunity and bidirectional capability make it suitable for EV charging systems, heat pumps, and solar PV.
Installer Tip: Choose the B Curve 20A for general-purpose circuits with steady loads. If you’re installing on circuits with frequent inrush (EV chargers, motors, pumps), select the C Curve version instead.
Key Features
- 20A, B Curve: Ideal for medium-load circuits with resistive demand
- 4 Pole Isolation: Disconnects live and neutral conductors
- Type A RCD: Detects AC and pulsating DC leakage
- Switched Neutral: Safer insulation resistance testing
- High Immunity: Reliable performance with EV, solar, and electronic loads
- Bidirectional: Suitable for renewable and inverter-driven circuits
- Compact: Single DIN module (17.8mm)
- Standards: BS EN 61009-1, 18th Edition Wiring Regulations
Other Variants in the WFR4 Series
| Model | Rating | Curve | Link |
|---|---|---|---|
| WFR406B-030 | 6A | B Curve | View Product |
| WFR406C-030 | 6A | C Curve | View Product |
| WFR410B-030 | 10A | B Curve | View Product |
| WFR410C-030 | 10A | C Curve | View Product |
| WFR416B-030 | 16A | B Curve | View Product |
| WFR416C-030 | 16A | C Curve | View Product |
| WFR420B-030 (This Product) | 20A | B Curve | – |
| WFR420C-030 | 20A | C Curve | View Product |
| WFR432B-030 | 32A | B Curve | View Product |
| WFR432C-030 | 32A | C Curve | View Product |
| WFR440B-030 | 40A | B Curve | View Product |
| WFR440C-030 | 40A | C Curve | View Product |
What’s the WFR420B-030 best for?
It’s designed for 20A circuits with moderate loads where fast fault disconnection and four-pole isolation are needed.
What’s the difference between B and C Curve?
B Curve trips faster for resistive circuits. C Curve tolerates higher inrush currents, ideal for EV, motors, and renewables.
Does this RCBO isolate neutral?
Yes – it has a switched neutral, ensuring complete disconnection.
Is it UK compliant?
Yes – fully compliant with BS EN 61009-1 and the 18th Edition Wiring Regulations.
Is it suitable for renewables?
Yes – its bidirectional design and high immunity make it compatible with EV chargers, solar PV, and heat pumps.
- SKU: WFR420B-030
- Device Type: 4 Pole Type A RCBO
- Current Rating: 20A
- Curve: B
- Residual Current: 30mA, high immunity
- Poles: 4 (with switched neutral)
- Isolation: Disconnects live & neutral
- Dimensions (HxWxD): 67.6 × 71.6 × 67.5 mm
- Mounting: 35mm DIN rail
- Compliance: BS EN 61009-1, 18th Edition Wiring Regulations
This RCBO must be installed by a qualified electrician in line with BS 7671. Ensure the rating and curve are matched to the load type and expected current.
- B Curve: For resistive loads and small inductive circuits
- Mounting: Standard 35mm DIN rail
- Testing: Switched neutral enables safe IR testing without disconnection
- Applications: Domestic, light commercial, EV-ready, solar, and heat pump circuits
