On 31/07/2018 11:09, Robin wrote:
On 31/07/2018 10:56, Andy Burns wrote:
wrote:

RCDs are to some extent sensitive to arcing as they fail to balance
the currents correctly at the high frequencies arcs contain. AFDDs
are just RCDs/RCBOs with less hf filtering.
I read that (some?) AFDDs use microprocessors to recognise the
signature of an arc.

Indeed.Â* Bloody complicated. See eg the (promotional!) Beama Guide to
Arc Fault Detection Devices (AFDD)

http://www.beama.org.uk/asset/D6E1ED...CA85BA77DEC2B/

What I've not seen is how they are tested after they are installed.

The installation instructions I have seen seem to suggest that pushing
the test button is all you can do.

BS EN 62606 (general requirements for AFDDs) gives quite elaborate tests
for the devices themselves to verify if they meet the required standard,
but these are not things one would typically want to deploy in the field
(e.g. use of sliding carbon rods setup as an arc generator, and a
guillotine type of mechanism designed to partially slice PVC flex to
create an arcing connection to one conductor and good connection to another)


--
Cheers,

John.

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