B Curve RCBOs for Domestic & Light Commercial Circuits
B Curve RCBOs are designed for standard domestic and light commercial circuits where inrush currents are low and predictable. They provide combined overcurrent and earth leakage protection in a single device, making them the preferred choice for modern boards where every circuit requires its own dedicated protection.
Read more
These RCBOs trip within the B-curve range, meaning they respond quickly to fault currents that reach three to five times the rated current. This makes them ideal for lighting circuits, ring finals, small power circuits and general domestic loads. Most models include a switched neutral and are suitable for both new installs and retrofit upgrades.
- Combined MCB and RCD protection in one device
- B-curve response for low-inrush domestic circuits
- Accurate disconnection times for 18th Edition compliance
- Switched neutral options for improved testing and safety
- Suitable for tight consumer unit layouts due to compact module size
Installers choose B curve RCBOs for clean circuit separation, reduced nuisance tripping and simpler periodic inspection. All product dimensions and ratings are provided within the individual listings.
Important: A B curve RCBO refers to the magnetic trip characteristic (3–5× rated current). This is different from a Type B RCBO, which relates to DC earth leakage detection for EV or inverter systems.
Arc Fault Detection A-Type RCBO – WFD132B-030 (32A, B Curve, 30mA)
£96.85
£145.99
The WFD132B-030 is a 32A, B Curve Arc Fault Detection (AFDD) RCBO, combining arc fault detection, 30mA Type A residual current protection, short-circuit, and overload protection in one compact unit. Fully compliant with BS 7671:2018 (18th Edition), it offers a reliable fire-safe solution for demanding...
Arc Fault Detection A-Type RCBO – WFD120B-030 (20A, B Curve, 30mA)
£96.85
£145.99
The WFD120B-030 is a 20A, B Curve Arc Fault Detection (AFDD) RCBO, combining arc fault detection, 30mA Type A residual current protection, short-circuit, and overload protection in a single compact unit. Fully compliant with BS 7671:2018 (18th Edition), it provides advanced fire prevention for modern...
Arc Fault Detection A-Type RCBO – WFD116B-030 (16A, B Curve, 30mA)
£96.85
£145.99
The WFD116B-030 is a 16A, B Curve Arc Fault Detection (AFDD) RCBO, providing arc fault detection, residual current protection (30mA), short-circuit, and overload protection in one device. Designed to BS 7671:2018 (18th Edition) standards, it offers advanced fire prevention and peace of mind for installers...
Arc Fault Detection A-Type RCBO – WFD110B-030 (10A, B Curve, 30mA)
£96.95
£145.99
The WFD110B-030 is a 10A, B Curve Arc Fault Detection (AFDD) RCBO, combining arc fault detection, residual current protection (30mA), short-circuit, and overload protection in one compact device. Built to BS 7671:2018 (18th Edition) standards, it delivers advanced fire prevention for modern electrical systems. Unlike...
Arc Fault Detection A-Type RCBO – WFD106B-030 (6A, B Curve, 30mA)
£96.85
£145.99
The WFD106B-030 is a 6A, B Curve Arc Fault Detection (AFDD) RCBO, combining arc fault detection, residual current protection (30mA), short-circuit, and overload protection into a single compact module. Built to BS 7671:2018 (18th Edition) standards, it delivers the highest level of fire prevention for...
What Is a B Curve RCBO?
A B curve RCBO is a residual current breaker with overload protection that trips magnetically between three and five times its rated current. This fast trip response makes it suitable for circuits with low and predictable inrush currents.
B Curve vs C Curve RCBO
Understanding RCBO curve types is essential when selecting protection:
- B Curve: Trips at 3–5 × rated current. Ideal for lighting and general domestic socket circuits.
- C Curve: Trips at 5–10 × rated current. Used for circuits with motors, pumps or higher startup loads.
If the connected equipment has minimal startup surge, a B curve device is normally specified.
Common Applications
- Lighting circuits (including LED)
- Ring final socket circuits
- General domestic power
- Consumer unit upgrades replacing split RCD boards
- Small commercial circuits with stable loads
Available Ratings & Configurations
Most B curve RCBOs are available in:
- 6A – lighting circuits
- 10A / 16A – radial circuits
- 20A / 32A – socket circuits and small appliances
- Single-module DIN rail format
- Switched neutral variants
Standards & Compliance
All devices comply with BS EN 61009 and meet the requirements of BS 7671 (18th Edition). They are fully compatible with modern metal consumer units and support independent circuit protection.