Rim fixed our under kitchen cabinet lighting that was not working.
The average modern consumer unit contains 3 main devices, a main switch, one or two RCD’s (residual current devices) and MCB’s (miniature current breakers) per circuit. The mains switch does exactly as you would imagine and immediately cuts all power flowing through the fuse box.
RCD’s and MCB’s protect against everything from overloaded sockets to earth fault currents. This is all included within a standard consumer unit and provides you protection from electric shocks and fires cutting by cutting the electricity before any harm can be done.
So, with all this protection already in the consumer unit why would you need an AFDD and what is an AFDD anyway!
An AFDD is an Arc Fault Detection Device which cuts electricity when it detects an electrical arc.
An electrical arc is created when electricity jumps between to conductive materials within a non-conductive medium for example: air. In low current instances this is just a small quick spark however if enough current is present this can generate and sustain a proper arc. Lots of everyday pieces of electrical equipment produce an arc during operation, for example in a light switch a small electrical arc is generated between contacts.
However unintentional arcing in a circuit is considered an arc fault, allowing current to jump between two cable cores and can generate temperatures in excess of 6000°C - more than enough to start a fire.
So, what is an arc fault detection device?
An AFDD is a device installed to your consumer unit to protect against arc faults. This works by monitoring the waveform of electricity being used to detect unusual signatures that would signify an arc. If an arc is detected power to the circuit is cut off minimising the risk of fire. AFDD’s are specifically designed to be more sensitive to arcs than regular circuit protection devices.
Recommendation of the installation of an AFDD can be as the result of a standard electrical safety check, with the most recent amendment to the 18th wiring edition the requirements are now as follows:
Arc fault detection devices conforming to EN62606 shall be provided for single phase AC final circuits supplying socket outlets with rated current not exceeding 32A in:
- Higher Risk Residential Buildings (HRRB)
- Houses in Multiple Occupation (HMOs)
- Care homes
- Purpose built student accommodation
In a typical residential application, this would apply to final circuits such as the power Ring Mains, Kitchen final circuits, and also any socket final circuit in a Garage Board if one is fitted.
Other scenarios when an electrician might recommend fitting arc fault detection devices to an installation, can include but are not limited to:
- Thatched roof houses due to the particular risk of fire.
- Heritage buildings
In these instances, it may be more than just circuits serving socket outlets which need AFDD protection. For example, a thatched roof bungalow may need arc fault detection installing on lighting circuits and other circuits which run through the loft space.
If you are concerned about your current installation or feel that you could benefit from the protection of having an AFDD installed, contact Safe Check Electrical for a free, no obligation quote. We can advise you on the best possible solutions to ensure complete safety and peace of mind.
