What is an Arc Fault Detection Device and what protection do they offer?Spencer Yates
An Arc Fault Detection Device offers additional protection against fire by mitigating the risk of fire in AC final circuits due to the effects of arc fault currents. An Arc Fault Detection Device uses digital electronics to analyse the waveform of an A.C. circuit to detect arc faults.
An arc fault occurs when loose or corroded connections make intermittent contact and cause sparking or arcing between the connections. This translates into heat, which will break down the insulations of the wire and potentially trigger an electrical fire. Such arcs can range in power and vary a great deal in both strength and duration. There are two possible types of arc fault; parallel arc faults are found with damage caused to insulation which allows current to flow between conductors, usually between phase and neutral. Series arc faults which are found in loose terminal connections, damaged cords or frayed/damaged conductors. These arcs are created in one conductor only, either phase or neutral.
AFDDs either as stand-alone devices or when combined with an MCB or RCBO, look to isolate a circuit at risk of fire caused by arcing within the cables or equipment. As part of our M2 AFDD range we have a single module Arc Fault Detection Device combined with RCBO, which offers complete circuit protection against over current, earth leakage, short circuit and arc faults. After tripping and upon resetting, the device’s LED status indicator will show the fault nature allowing you to progress accordingly.
Since the redraft of regulation 421.1.7 in BS7671 (18th Edition Amendment 2), AFDDs conforming to BS EN 62606 shall be provided for single-phase AC final circuits supplying socket-outlets with a rated current not exceeding 32A in:
- Higher Risk Residential Buildings (HRRB)
- House of Multiple Occupancy (HMO)
- Purpose-built student accommodation
- Care Homes
For all other premises, the use of an Arc Fault Detection Device is recommended for single-phase AC final circuits supplying socket-outlets not exceeding 32A. Where used, AFDDs shall be placed at the origin of the circuit to be protected.
For more information on our M2 Arc Fault Detection Device offering, please contact our helpful sales team.