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.

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.

So, an A.F.D.D. trips off due to a fault, then is reset by somebody but it won't stay on. Do the flashing lights stay on that identify the type of fault?

AND, what benefit is there in knowing the type of fault anyway by the flashing lights, as an electrician will normally and hopefully locate it by conventional means anyway. 

Z.

Zoomup said:

So, an A.F.D.D. trips off due to a fault, then is reset by somebody but it won't stay on. Do the flashing lights stay on that identify the type of fault?

AND, what benefit is there in knowing the type of fault anyway by the flashing lights, as an electrician will normally and hopefully locate it by conventional means anyway. 

Different manufacturers have different implementations, and you'd need to check specific products out, but why wouldn't the electronics inside the AFDD be able to stay on from the input, whilst the output circuit (containing the supposed fault) is disconnected?

I was wondering about the longevity of these things. How many non-arc faults - over-current/short circuit -  will they tolerate before the electronics gives up the ghost? There's a arc extinguishing chute in there somewhere which needs to snuff out heavy fault current arcs withing the device itself.  I know that certain brands of RCBO tend to die after relatively few operations under service conditions. That'll be one hell of an expensive 'fuse' to replace when it fails.

All protective devices are only specified to operate for a finite number of times (in the case of fuses themselves, 1).

Indeed. But there is a lot of variance in terms of resilience between products from different manufacturers when it comes to electro-mechanical devices, and now we intend to introduce fragile silicon chips into the mix.

I can foresee where that might lead us. whereby in the event of a fault, the 'licenced control box engineer' will be called out to diagnose and remedy the problem. He will most likely have to have a annual subscription to the company which supplied the control software in order to access the the internals with his laptop. This will be on some 'cloud' or other, with a password or PIN which changes monthly. He will have to be paid up in order to 'reset' any device which has disconnected once the fault has been diagnosed and cleared. Of course, if the CPU in the consumer unit has died, that means a very expensive job.

To me this is a nightmare scenario - there appears to be an overriding tendency to over complicate simple processes to no positive advantage.

'Cloud' means someone else's computer beyond your control, and 'software' should translate to 'nightmare', especially for early adopters.And of course, product life cycles get shorter and shorter, the ongoing provision of backups and security patches represents an expense to the manufacturer and is quickly dropped in favour of the 'Next Big Thing to be released the following year. Witness all those hacked doorbell cameras and other 'smart' devices around the home recently.

Try 'hacking' remotely into the humble 3036 fusebox and let me know how you get on.

"...and the actual death toll was reduced to about a third of that"

 none of it can be verified and proved to an agreed consensus between subject competent folks and the ones who are questioning what's gone on and the claims of effectiveness and success etc are maligned, ridiculed and suppressed ...  :-)

whjohnson said:

and now we intend to introduce fragile silicon chips into the mix

They are here already in other protective devices - for HV and very large LV installations ... and have been for over 25 years.

psychicwarrior said:

and the claims of effectiveness and success etc are maligned, ridiculed and suppressed ...  :-)

Isn't that where this thread started, in respect of AFDDs, though?

I agree, in the grand scheme of things, it's really difficult, and, as I pointed out with the discussion on vehicle safety equipment, there are definitely 'different realities' depending on your own point(s) of view, various 'vested interests' (even if it's only a desire, or encouragement, to not comply with the standard or legislation), the validity we each ascribe to assumptions and statistics, etc.

psychicwarrior said:

and the claims of effectiveness and success etc are maligned, ridiculed and suppressed ...  :-)

Isn't that where this thread started, in respect of AFDDs, though?

I agree, in the grand scheme of things, it's really difficult, and, as I pointed out with the discussion on vehicle safety equipment, there are definitely 'different realities' depending on your own point(s) of view, various 'vested interests' (even if it's only a desire, or encouragement, to not comply with the standard or legislation), the validity we each ascribe to assumptions and statistics, etc.