Fusebox AFDD 30mA RCBO
ARC Fault Detection Devices are protective devices installed in consumer units to provide protection from arc faults. They use microprocessor technology to analyse the waveform of the electricity being used to detect any unusual signatures which would signify an arc on the circuit. This will cut off power to the affected circuit and could prevent a fire. They are far more sensitive to arcs than conventional circuit protective devices.
Like a Residual Current Circuit Breaker (RCCB) or Residual Current Breaker with Overcurrent protection (RCBO), AFDDs usually incorporate a test button which can be operated by the end-user to prove the mechanical operation of the device.
In the current edition of the IET Wiring Regulations, BS 7671:2018, it is a recommendation to install AFDDs but the customer can choose to omit them. However, this decision should be based considering any relevant risk and safety factors against the cost of installation.
AFDDs are worth consideration if there is an increased risk of fire, such as:
- Premises with sleeping accommodation, for example, houses, hotels, and hostels.
- Locations with a risk of fire due to the nature of processed or stored materials, for example, stores of combustible materials.
- Locations with combustible constructional materials, for example, wooden buildings.
- Fire propagating structures, for example, thatched buildings and timber-framed buildings.
- Locations with endangering of irreplaceable goods, for example, museums, listed buildings and items with sentimental value.
It may also be worth speaking to your insurance company, to see if they would payout in the event of a fire if AFDDs were not installed as recommended in BS 7671:2018.
Do I need to install an AFDD on every circuit?
In some cases, it may be appropriate to protect particular final circuits and not others but if the risk is due to fire propagating structures, for example, a timber-framed building, the whole installation should be protected.