Dual RCD vs RCBO vs AFDD

Choosing a consumer unit involves more than comparing prices. The protective devices inside it perform different jobs, and the appropriate arrangement depends on the installation.

Three terms you may encounter are Dual RCD, RCBO and AFDD. Understanding their roles can help you ask useful questions when discussing an upgrade.

What Is a Dual RCD Arrangement?

A dual RCD consumer unit divides circuits between two residual current devices. Each RCD provides residual-current protection for a group of circuits, while circuit breakers provide protection against overloads and short circuits.

If an RCD operates, the circuits in its group can lose power together.

What Does an RCBO Do?

An RCBO combines residual-current protection with protection against overloads and short circuits.

Using an individual RCBO for each circuit helps limit the effect of a fault to that circuit. Other circuits can remain supplied, depending on the fault and installation arrangements.

What Does an AFDD Add?

An arc fault detection device identifies certain electrical arcing faults and disconnects the affected circuit. It provides an additional protective function associated with reducing electrical fire risk.

AFDD protection does not replace the need for other appropriate protective devices or sound installation work.

Which Option Should You Choose?

The decision should follow an assessment of the property, circuits and protection requirements. Ask the electrician to explain the proposed specification and why it suits the installation.

Spark’s indicative consumer unit options are £699 for a Dual RCD Board, £825 for a Full RCBO Board and from £1,300 for RCBO with AFDD. The final scope and price are confirmed following assessment.

To discuss an upgrade in Liverpool or Merseyside, use Get Started and include any existing electrical report and a photograph of the consumer unit taken safely with its cover in place.