The defence would be that the customer would not pay for them so I could not supply and fit them.

Z.

Here are some recommended products/services. Shall we buy them all?

https://www.youtube.com/watch?v=sitq1dV9YbE

Z.

A.F.D.D.s, ramblings about 'em.

https://www.youtube.com/watch?v=KpxXrAnzp2E

Z.

There does seem to be a slow but steady increase in such devices being specified, even for those installations which fall under the “recommended” heading. 
I have a large 2396 class underway at the moment with chaps reporting consultants specifying AFDDs on all socket circuits up to and including 32A irrespective of location. Mad it may well be, but that will commence the custom and practice albeit at snails pace. 
As someone with a keen interest in fire safety, I think money could be better spent. 

So even "consultants" can be fooled by a non statutory British Standard "recommendation" then. 114.1. So it appears that most of the people can be fooled most of the time by manufacturers of A.F.D.D.s. and their supporters 

Z.

Why are consultants being “fooled”. Is it unreasonable for them to take the same view as BS7671 and simply implement their own recommendations? 
Whether the client runs with their proposals is another matter.

The problem Lyle is the level of engagement with the client/project manager. Neither are at all knowledgeable about the subtle wording in BS7671, usually just calling for compliance, but compliance is a difficult term for the consultant, because the last thing he wants is "someone" coming after installation and demanding AFDDs!

He is a pet gripe: (no particular disrespect to any reading here). There are a surprising number of "H&S wallahs" about who have very little knowledge of anything much technical, their thing is simply the paperwork. One of their principal interests is a file of risk assessments for everything that can be imagined, and a good number of things that can't. An RA is intended to be a simple risk management tool. but these chaps (usually) think it is a get out of jail card for them. So all these bits of paper have lists of risks (alleged), a column with ticks all marked critical, and a reduction comment to get to a level they note as acceptable.  In some cases they might be right, but in many the risk is magnified out of all proportion because there is no reference to anything showing the risk level in the past, from the event! The client is immediately frightened into spending loads of money to prevent the most unlikely accident.

We all know that fixed wiring electrical fires are quite rare, and there are a number of very specific reasons why they may be caused, the primary one being loose connections as I discussed above. Are arc faults of the kind targeted by AFDDs common or more importantly how common? Are there many circumstances available where the arc conditions (above) can be met? Has anyone collected any data, particularly forensic fire Engineers? Can we get one to say that this is a common cause of serious fires? Strangely, probably not.

My case for the defense M'lord.

One point - since AFDDs are recommended on circuits with <=32A socket outlets, it seems that the regulation is more aimed at arc faults in equipment and flexes than in the fixed wiring. So the bit about fixed wiring arcs being rare may not be relevant.

I would like to suggest to the court that had the plaintiff bears some responsibility, as had he ordered the fish, as was recommended, then his wife would not have been poisoned by the goulash, and the restaurant would not have burnt down later the same night as the defective hob would not have been used.

Perhaps to some folk it is that sort of "Mafia Godfather" recommendation you really cannot refuse.

M.

PS or more like the old joke.

That is an interesting point Wally, but those selling them seem determined that the problem is fixed wiring. Surely if it is not, BS7671 is not the document that should be modified, shouldn't it be that the appliances should be made to a proper standard?

If it were admitted that the problem were certain appliances (someone must know which as they must take 3A or more) then that is where the device is required?

Interestingly, I have also been looking very carefully at type A,B F etc RCDs and what equipment could cause the alleged "DC" leakage. A lot of playing with a circuit simulator is proving very interesting. We have had "electronic" appliances for a long time now, I looked at one yesterday, a boiler that had a switch mode power supply fault. Essentially I could find no way that a type AC RCD would not be adequate as there were no credible faults that could occur and not blow the 630 mA internal fuse. Further information later!