Arc Fault Detection A-Type RCBO – WFD140B-030 (40A, B Curve, 30mA)

The WFD140B-030 is a 40A, B Curve Arc Fault Detection (AFDD) RCBO, designed to deliver maximum protection against arc faults, earth leakage, overload, and short circuits in one compact unit. Built to BS 7671:2018 (18th Edition) standards, it provides fire-safe reliability for high-load domestic and commercial circuits.

Unlike a standard RCBO, this device features microprocessor-driven arc fault detection that constantly monitors electrical waveforms. It trips instantly when dangerous arcs occur due to damaged insulation, loose terminals, or faulty appliances. Both live and neutral poles are isolated for complete safety.

Protective Coverage

This AFDD RCBO combines:

• Arc Fault Detection – both series and parallel
• Residual Current Protection – Type A, 30mA (AC + pulsed DC)
• Overcurrent Protection – overload and short-circuit
• Overvoltage Protection – trips at 275V ±5%

Variant Comparison

• SKU: WFD140B-030
• Type: AFDD + Type A RCBO
• Rating: 40A
• Curve: B
• Residual Current Sensitivity: 30mA
• Breaking Capacity: 6kA
• Operating Voltage: 230V AC, 50Hz
• Arc Fault Detection: Series & Parallel
• Additional Protection: Overcurrent, earth leakage, overvoltage (275V ±5%)
• Isolation: Switched neutral – disconnects live and neutral
• Mounting: 1 module DIN rail
• Dimensions: 17.8 × 116 × 76 mm
• Compliance: BS EN 61009-1, BS EN 62606, BS 7671:2018 (18th Edition)

Must be installed by a qualified electrician in accordance with BS 7671. The 40A AFDD RCBO is intended for high-demand final circuits in residential and commercial installs.

• 40A rating suited for heavy-load circuits
• Single-phase 230V AC operation
• 1 module DIN rail (17.8mm width)
• Not suitable for DC applications
• Compatible with WCED consumer units and distribution boards

What is the WFD140B-030 used for?

It is designed for high-demand circuits such as heavy appliances, commercial loads, and circuits in HMOs where fire safety is critical.

Does this AFDD RCBO fully isolate the circuit?

Yes – it disconnects both live and neutral poles for maximum safety.

Is this product 18th Edition compliant?

Yes – it meets BS 7671:2018+A2 and is certified to BS EN AFDD/RCBO standards.

What’s the main difference from a standard 40A RCBO?

The AFDD RCBO detects arc faults caused by faulty connections or degraded wiring, which standard RCBOs cannot detect.

What other ratings are available?

The WFD1 Series includes 6A, 10A, 16A, 20A, and 32A. This page is for the 40A WFD140B-030.