Arc Fault Detection A-Type RCBO - WFD1**B-030
The WCED WFD1 Series Type A AFDD RCBO is a next-generation circuit protection device that combines arc fault detection, residual current protection (30mA), short-circuit and overload protection into one compact, single-module unit. Designed to meet BS 7671:2018 (18th Edition) safety standards, it offers the highest level of fire prevention for...
The WCED WFD1 Series Type A AFDD RCBO is a next-generation circuit protection device that combines arc fault detection, residual current protection (30mA), short-circuit and overload protection into one compact, single-module unit. Designed to meet BS 7671:2018 (18th Edition) safety standards, it offers the highest level of fire prevention for modern electrical installations.
Unlike a standard RCBO, this device includes an Arc Fault Detection Device (AFDD) powered by a built-in microcontroller. It constantly monitors the electrical waveform and identifies dangerous arc impulses caused by worn wiring, poor connections, ageing circuits, heavy loads, or faulty appliances. Once detected, the device trips immediately, cutting both live and neutral poles to prevent fire risk.
Protective Coverage
The WFD1 range combines the functions of an AFDD, MCB, and Type A RCD. This ensures protection against:
- Series and parallel arc faults (a common cause of electrical fires)
- Overloads and short circuits
- Residual current leakage (Type A – detects AC and pulsating DC)
- Overvoltage conditions (trips at 275V ±5%)
Ideal Applications
AFDDs are recommended in the 18th Edition for circuits supplying sleeping accommodation, HMOs, student housing, hotels, rental properties, and commercial premises where fire risk is higher. They are also suitable for final circuits supplying sockets, lighting, and high-demand appliances where hidden arc faults may occur.
Available Variants
B Curve, 30mA sensitivity, in the following ratings:
- 6A – WFD106B-030
- 10A – WFD110B-030
- 16A – WFD116B-030
- 20A – WFD120B-030
- 32A – WFD132B-030
- 40A – WFD140B-030
Each unit is DIN rail mounted and only 17.8mm wide, making it a space-saving, high-performance upgrade for new or existing consumer units.
What does an AFDD RCBO do?
An AFDD RCBO combines standard protection (overload, short circuit, earth leakage) with arc fault detection. It disconnects power when dangerous electrical arcs occur, preventing electrical fires.
Where are AFDDs required?
BS 7671 recommends AFDDs in circuits supplying HMOs, student accommodation, rental properties, and commercial buildings, as well as locations with sleeping risk or combustible materials.
What’s the difference between Type A and Type AC?
Type A devices detect AC faults as well as pulsating DC residual currents. This makes them suitable for modern circuits with electronic loads (LEDs, EV chargers, appliances).
Does this device fully isolate the circuit?
Yes – the WFD1 range features a switched neutral, ensuring both live and neutral conductors are disconnected for maximum safety.
How wide is it?
At just 17.8mm wide, it takes up a single DIN module in the consumer unit.
- Type: Single Module AFDD + Type A RCBO
- Rated Current Options: 6A, 10A, 16A, 20A, 32A, 40A
- Curve: B Curve
- Residual Current Sensitivity: 30mA
- Breaking Capacity: 6kA
- Operating Voltage: 230V AC, 50Hz
- Arc Fault Detection: Series & Parallel arc faults
- Additional Protection: Short circuit, overload, earth leakage, and overvoltage (275V ±5%)
- Isolation: Disconnects live and neutral poles (switched neutral)
- Mounting: 1 Module DIN rail
- Dimensions: 17.8mm (W) x 116mm (H) x 76mm (D)
- Standards: BS EN 61009-1, BS EN 62606, BS 7671:2018 (18th Edition)
AFDDs are strongly recommended under the 18th Edition for circuits supplying sleeping accommodation, HMOs, student housing, and premises with high fire risk. Key installation guidance includes:
- Install on final circuits requiring enhanced fire prevention
- Ensure correct rating (6–40A) for circuit demand
- Suitable for single-phase 230V AC circuits
- Not designed for DC networks
- Compatible with WCED consumer units and TPN boards
