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.

I wonder if the flashing sequence for 'arcs' is triggered under the 'Don't know' category'?

The biggest objection to fitting this new expensive stuff is the cost. The new stuff has virtually all arrived together. S.P.Ds, A.F.D.Ds, new types of R.C.D. that advertise that they are resistant to D.C. "blinding". The consumer just can't be expected to pay for stuff that they do not understand and can't possibly afford.

Z.

"Joyce, was it dot dot dash or dash dash dot for a trip by a arc fault?"

"No John I think it was dot dot dot dash"

"Fred's down the road is green, red, red.

"Where's that instruction sheet that the sparks left"

"Oh, I think that the dog ate it"

"Lets go online"

"We can't, the powers off and the router has crashed".

"Oh Ek!" "And wasn't Fred's green, green, red?

Z.

Zoomup said:

The biggest objection to fitting this new expensive stuff is the cost.

Yes, that was the case with RCDs. I'm sure the cost will come down ... already started to happen.

Zoomup said:

The consumer just can't be expected to pay for stuff that they do not understand and can't possibly afford.

421.1.7 Arc fault detection devices (AFDD) conforming to BS EN 62606 shall be provided for single-phase AC final circuits supplying socket-outlets with a rated current not exceeding 32 A in:
• Higher Risk Residential Buildings (HRRB)
• Houses in Multiple Occupation (HMO)
• Purpose-built student accommodation
• Care homes.
NOTE 1: Higher Risk Residential Buildings are assumed to be residential buildings over 18 m in height or in excess of six storeys, whichever is met first. It is anticipated that in many areas higher risk residential buildings will be defined in legislation which can be subject to change over time, as well as in risk management procedures adopted by fire and rescue services. Current legislation should be applied.
For all other premises, the use of AFDDs conforming to BS EN 62606 is recommended for single-phase AC final circuits supplying socket-outlets not exceeding 32 A.

In the highlighted part ('shall'), likely only the first bullet would be consumers as the client? In those premises, is it not pertinent to simply say it's there to help protect against fires? Just plain and simple? Any further questions in those premises, the answer could be "Introduced in the Amendment following Grenfell".

So, no long explanations.

Similarly, it could be offered in other premises quite easily, "There's a new device available to help stop fires. A bit expensive. Would be required if I were doing this job in a block of flats ... recommended in the Wiring Regs."

Zoomup said:

"Oh Ek!" "And wasn't Fred's green, green, red?

I agree ... what's more frustrating with the situation about indications, is that there's actually a standard that could be used, BS EN 60073. Yes, it applies to industrial controls and similar uses, and not mandated for other products, but nevertheless, would provide some uniformity to the situation regarding colours of indications and use of that with flashing etc.

Much better than "well, a blue LED looks good, let's just confuse everyone and use that. Now, how many flashes for standby?"

Zoomup said:

"Oh Ek!" "And wasn't Fred's green, green, red?

I agree ... what's more frustrating with the situation about indications, is that there's actually a standard that could be used, BS EN 60073. Yes, it applies to industrial controls and similar uses, and not mandated for other products, but nevertheless, would provide some uniformity to the situation regarding colours of indications and use of that with flashing etc.

Much better than "well, a blue LED looks good, let's just confuse everyone and use that. Now, how many flashes for standby?"

RCDs, SPDs, Fuses, MCBs etc are merely passive components. We know how they are supposed to work and can test them up to a point. They are 'dumb' and just sit there until the condition they are designed to address occurs.

AFDDs are active devices which contain a cpu and are driven by algorithms. One might say they are semi-'smart'.

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

We have all witnessed how good algorithms are when it comes to writing and applying them into real world problems.

I recall a certain now-infamous Professor predicting something like half a million deaths in the UK at the beginning of the pandemic..................

Then of course, we have algorithm-driven 'bots' which drive search engines and the like. Type certain words into a search engine and you might not get what you were looking, but something embarrassingly different!

It wouldn't take a great leap into the unknown to predict 'smart' consumer units, which would be capable of monitoring a preloaded load profile for every appliance in your house. Couple this via some metadata to your smart meter and your supplier could look up what you have switched on at any time.

"Flashing red light on Supplier's control room console summons the attention of the keyboard operative  - Mrs Gumby has her washer and dryer on and the windmill isn't turning - switch her off NOW!"

Down the wire goes the 'Make It Dead' signal to the relevant 'smart' circuit breaker in Mrs Gumby's cu  and off goes her washing until the wind blows again.

Just because we might be able to do something doesn't always mean that we should.

whjohnson said:

I recall a certain now-infamous Professor predicting something like half a million deaths in the UK at the beginning of the pandemic

That was the predicted death toll for if the government took no action. So the government took lots of actions - lockdowns etc - and the actual death toll was reduced to about a third of that.

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.