The legislative system is very good at updating and consequential amendments.

I'm not so sure. The ESQCR seems to be stuck on the unamended 17th Ed (last amended 2009 as far as I can tell),


The latest version of AD-P seems to refer to the 17th+AMD 1.


and of course the The Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020 relies on the vanilla 18th Ed.


While I understand the desire for 'non ambulatory' legislation, I think it could have been handled better. Say have one item of legislation which did nothing but specify which version of the wiring regs the law required, then have everything else refer to that. Then when there are updates only simple single change to one item of legislation would be required and everything would automatically remain consistent.


  -  Andy.

gkenyon:

I don't disagree with statement of cost regarding AFDDs, but I perhaps hold the view that, just like RCDs, the costs will come down and the devices will improve.


And once the devices have improved, and be shown to work, in the sense of reducing fires damage and fatality, and the costs come down to a manageable level, then, and only then, is the time to mandate them onto the majority of circuits in the standards.

If we look at the history of when RCDs came into the regs, this is happened gradually over more than 3 decades.

In 1981 the 15th edition (oh vexed matters of earthing)  first required 30mA RCD for sockets supplied by a TT system, and for circuits intended to supply items to be used outdoors of less than 32A and likely to be touched.   (Reg 471-13)

At that time VOELCBS were still accepted on TT systems Reg 471-15.

Now while over the next 10- 20 years TT systems slowly lost VOELCBs (regs changed 1984 ish ) and acquired RCDs, the idea that this RCD idea should be extended to include general sockets that might occasionally be used to power equipment outdoors did not really take off , and had to wait until the 16th edition 2001 to be tightened to  " any socket that might reasonably supply portable equipment for use outdoors". Enter the mass installation of RCD sockets by the back door for the lawnmower in the garden.

Even by 2008, in the 17th edition, although RCD protection was now required for all sockets for use by ordinary persons, there was an opt out for specific items such as fridges and freezers, and for whole systems under appropriate supervision.

Not until the 18th edition have RCDs become ubiquitous. In the mean time they have also developed, types AC, A, B etc reflecting the fact that the original RCD designs were not good in all cases.


A similar phased approach for AFDDS would mandate them only for places where the risk of an arc doing more than self extinguish is credible, and where AFDDs stand some chance of performing an ADS function. The haste is indecent.

Thank you, Graham. Yes the haste is indecent, and suggesting that the device "may be improved" over time is possible. But there is absolutely no reason for manufacturers to do this! Once you have a product you sell a few billion pounds worth, by regulation, and laugh all the way to the bank! If what you suggest is true, we should see an American AFDD with a spectacular performance, but we don't! It is also wrong to suggest that the RCD introduction was without difficulties. RCDs are still not satisfactory really, in that they can trip due to all kinds of non-fault things, particularly current transients from motor starting. They have not improved over the period, although prices have dropped a bit (<50%).


Technically we should only need one AFDD per installation. However, so far no one has been able to separate an arc current from a load current, and the arc current must pretty much be the ONLY load on a circuit to operate the AFDD. The arcs which are being detected are not defined properly and are unlikely anyway in a T&E installation. The function test specified is grossly inadequate in that it copies no known fault condition (micrometer anyone?). It is very difficult indeed to establish an arc between 2 copper conductors which is not a short circuit and therefore trips the CPD anyway. Earth arcs will always trip the RCD. I know this because I have tried very hard to test the function! I am happy to demonstrate the ineffectiveness to anyone who will look. Series arcs are extremely difficult to test, and need to be continuous for seconds at a time. Is this a normal fault? No, real overheating of series circuits is by resistance not arcing, arcing circuits tend to weld up solid!


The electronics in an AFDD cost at most a couple of pounds and a selling price of £200 or even £100 is ridiculous. A CU costing £1500-2000 is ridiculous. An industrial final circuit board costing £20,000 is ridiculous! The lack of a 3 phase device, if it is so good, is ridiculous.


In this case, the cart is so far ahead of the horse that it cannot even be seen. The manufacturers do not seem to want to answer all these questions or demonstrate effectiveness. The proof is available from the USA, they need to collect and study the fire statistics, which should show a huge improvement in safety. As far as I can discover, they do not; they are not easily available and a source I did find has now been taken down!


I may sound skeptical, but not without reason. Everyone who has tried an AFDD finds it difficult to trip with "real" kinds of faults. There are several demonstrations on Youtube, the best is probably John Ward. Video


This is a forum fault!!!   After posting a URL The cursor is still in URL blue underline mode


If anyone would like to provide modest funding, I will find a better product design, that is what is required. The current product is seriously flawed yet is mandated by BS7671. Duh!

AFDD's are not a new development and are not new technology. I find it hard to believe that their cost of £150ish is going to come down to the RCBO/RCD level of as these weren't that expensive when they were 10 years old. Until they are £25 then they might be considered a affordable

The regs are increasingly used for forcing demand. The manufacturers require growth, so the electrician is forced to be their salesperson.

This video is also well worth a look. The products have completely different levels of function!  AFDD video 2

I am all for foundation earthing (or its equivalent involving a ring of buried copper, the name escapes me right now). The tricky bit as usual will be getting the general builder to make our lives easy :( Foundation (or rebar) earths have been used for years in the US, where they're known as Ufer grounds (after the chap who suggested the idea, I believe). Brilliant idea.


As for AFDDs... the issue I think is not so much the cost ( as the RCD path taught us, demand will drop the price hugely), but whether they actually DO anything.  And combining it all into one unit leaves me a little cold. I do not trust active electronics in a safety critical role unless maintained regularly. I for example would NOT rely on a smoke alarm system that was not regularly tested, nor indeed the ABS or airbags in my van unless serviced regularly. Domestic switchgear tends to go for up to a decade (even with EICR's being carried out) without a single test.


RCBO's are less of an issue in this regard, because they simply add the RCD functionality onto a normal MCB. Does anyone have the cash to take apart an AFDD and see if this is the case there also? If so, I would be less reticent.

This is the inside of an AFDD. A few pounds worth altogether.
Youtube link