A.F.D.D. with a combined M.C.B. unit, the tripping may just be due to overcurrent, so we may not know which part of the device has caused the tripping off.

All the ones I looked at had some means of indicating the cause of the trip - usually coloured/flashing LED - different flashes for Arcs, RCD or overcurrent - so probably better than many an RCBO.

  - Andy.

Then when Mrs. Gumby's clothes get smelly and mouldy in the machine she has to put them on at least one or maybe two new wash cycles to remove the smells.

Z.

And she can't dry them outside because it's raining and the wind isn't blowing!

Never mind eh, Mrs Gumby is delighted to be doing her bit for the environment despite being charged a hefty premium to put up with regular supply interruptions.

I wonder which of his algorithms told him it was ok to visit his German mistress despite his own advice to the rest of us?

whjohnson said:

AFDDs are a completely different ballgame to the other passive devices I have mentioned.

Circuit-breakers have, for some time, had intelligence in them. Granted, not the "for use by ordinary persons" breakers, but it's nothing new to me to see "computers" in protective devices.

I think you're dead right, that there's way more mileage out of "SMART" devices to be marketed in the future.

Wife phoning husband who is at work.

"George there's an  arc fault on our wiring I'm worried about a possible fire"

George; "Are you sure dear?"

Wife. "Yes George there are flashing lights."

George. "Can you see or smell smoke?"

Wife. "No George, but the lights are still flashing."

George. "I have an important meeting in 30 minutes here."

Wife. "Can't you come home George, I'm very worried."

George rushes home.

George upon inspecting consumer unit.

"Oh, dear, there's nothing wrong. It's just the flashing lights on the smart meter dear."

Wife. "Well they were signalling a fault dear. They were. Honestly."

Z.

Dear, dear will you spend some time viewing this please........?

Do I really have to?

AFDD - Arc Fault Detection Device - Part 1 - Bing video

"But Dear, when the device switches off after eventually detecting an arc fault it needs to be turned on, possibly to a faulty circuit, before it reveals its reason for switching off. I though that we should not energise a faulty circuit or faulty appliance. That could be dangerous."

Z.

Zoomup said:

"But Dear, when the device switches off after eventually detecting an arc fault it needs to be turned on, possibly to a faulty circuit, before it reveals its reason for switching off. I though that we should not energise a faulty circuit or faulty appliance. That could be dangerous."

Oh dear.

What the FIRST thing that happens when a domestic RCD trips (or, as I've seen, RCD trip at work, that's intended for operation by ordinary persons)?

A user tries to reset it. Simples. Same with mcb's ... only after it trips again will anyone investigate further.

I don't really see that as a clear argument that AFDDs are dangerous. Sorry Zoomup 

gkenyon said:

A user tries to reset it. Simples. Same with mcb's ... only after it trips again will anyone investigate further.

Father always said not to replace a fuse until the cause of the blow had been found, but I think that one might be permitted one try with an MCB.

At work, not too long ago, we were informed that we could not have tea because there was no power to the water heater. This was a serious matter. I found a CU, opened the door, saw a tripped MCB and reset it. Doubtless I broke many rules (including standing on a chair rather than a ladder) but I fixed the problem.

A similar near existential crisis at our place had a temporary 3 phase extension lead running between two buildings and up a stairwell to the offending coffee room in  under an hour. That is because it was the one used by site services. The cynic in me suspects that anyone else  would have had to put a ticket in and wait..

Mike

Recently a fast food takeaway had a problem with a walk in chiller room cooling system. It kept tripping everything off including chest freezers full of food on the same circuit. The compressor motor had gone short circuit L to E. The owner had tried to run the walk in chiller room via a long extension lead on a good working socket outlet. As the compressor was still faulty it caused an immediate tripping off of a M.C.B. It also damaged the socket outlet switch so that it became faulty. It is not a good idea to liven up a faulty circuit. The first trip tells you that something is faulty. Don't tempt Darwinism.

Z.

Recently a fast food takeaway had a problem with a walk in chiller room cooling system. It kept tripping everything off including chest freezers full of food on the same circuit. The compressor motor had gone short circuit L to E. The owner had tried to run the walk in chiller room via a long extension lead on a good working socket outlet. As the compressor was still faulty it caused an immediate tripping off of a M.C.B. It also damaged the socket outlet switch so that it became faulty. It is not a good idea to liven up a faulty circuit. The first trip tells you that something is faulty. Don't tempt Darwinism.

Z.