AFCI into Wiki FAQ?

AFCIs are little known in the UK and aren't used in normal low-voltage wiring installations. Compared with the US we have lower load currents, better quality wiring accessories and the use of aluminium conductors below 16 mm^2 is forbidden - all contributing to much lower inherent fire risk.

However the 18th edition of the regs is on its way (due July 2018) and arc fault detection devices - AFDDs - may be introduced. To quote from

"It is recognised that RCDs can reduce the likelihood of fires associated with earth faults. However, whilst RCDs can detect earth faults they aren?t able to reduce the risk of electrical fire due to series or parallel arcing between live conductors because there is no leakage current to earth. Also, it is understood that the impedance of a series arc fault reduces the load current, which will keep the current below the tripping threshold of the circuit-breaker and the circuit-breaker may therefore not operate to disconnect the circuit.

"For this reason details will be included in BS 7671:2018 for the installation of arc fault detection devices (AFDDs) to mitigate the risk of fire in final circuits of a fixed installation due to the effect of arc fault currents."

Whether they will be optional or mandatory remains to be seen...

Write a page on them if you like. But I reckon it belongs more on an ANAQ than a FAQ.

NT

This reads a bit like "we've patented this, how do we force people to fit them?"

If they look for skewed mains waveforms, are dubious SMPSUs going to nuisance trip them?

Will they be able to be fitted by existing electricians or will there be a new AFCI qualification and self-certification scheme???

Owain

So what happens when I want to use my electric welder? And what about fluorescent lights? (Assymetric waveforms) Or is the assumption we'll all be on LEDs?

So far I don't think they have had a mention, since their use in domestic environments in the UK is almost unheard of.

Might be worth adding a AFDD / AFCI article if they are threatening to include it in the 18th edition.

(You can have the honour of adding the 600th article to the wiki ;-)

The wikipedia article mentions nuisance trips. I'd guess they are quite a problem.

OTOH the article helpfully translates above 1000°C as 1832°F, which gives me a feel for the quality.

Andy

I've created a page AFCI, with links to and from the RCD page. It captures the essential content, but needs more work on formatting - but later, as a SWMBO interrupt is imminent.

ASIDE: WikiBugLet !!! -- At the foot of the Wiki pages, as for example "This page was last modified on 2016-09-10, at 18:46:55.", a "GMT" (or "UTC)" seems needed.

P.S. During the interrupt, John Rumm added meat to the page.