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AFDDs AMD 2

In response to the suggestion of separate threads for individual changes to the 18th I thought I would start this one for AFDDs.


So what are the forum members views on the new requirement for AFDDs?


What is the safety case for the change? E.g impact on public safety, fires etc.Evidence?


What is the impact on the installation industry? How easy to fit, cost advantages disadvantages etc?


Will you feedback to the BSI on the changes and what will you say?


  • Hire a qualifed experienced electrician who will make sure that all your electrical terminations are correctly tightened..

    Although we know that this is unlikely to happen 100% and some will slip though.

    The fault may well fall on the design, manufacture and installation at the manufacturing stages of ready assembled accessories such as distribution boards.

    I remember installing a CCU where, a few weeks later, the client complained that one of the fuse holders flew off out of the fuse board. It was later found that the fuse holder in question was attached lose on the live rail and was not checked at the installation stage.

    Legh
  • To me, the real issue is where is the evidence to say that they will make a significant difference?

    It is very easy to get into adding significant cost into a project to reduce a very low level of risk by an immeasurable amount.

    I know "Joe Public" doesn't like to hear it, but there is a point where the cost of reducing incidents / accidents cannot be justified.

    Chris
  • Did you install AFDD in your own house when you added surge protection?


    Personally I have considered installing surge protection at home and upgrading the RCDs in the consumer unit from Type AC to Type A.


    I have not considered replacing the plastic enclosure of the consumer unit or installing AFDDs.


    I have only ever heard of one incident that was identified by an insurance assessor as being due to “a pinched cable” causing an arc fault resulting in a fire that wasn’t prevented by the MCB and RCD, everyone else thought an ember falling out of the wood burning stove caused the fire. 


    So so I cannot say I personally feel to urge or the necessity to install AFDD in my own home.


     Andy Betteridge
  • For reference, below is the proposed new wording in the AMD2 DPC (copied from the main thread)

    9eacc7941e802182b9a09cb3c3cee13c-original-421-1-7.jpg
  • What coding are you going to use on this one John? based on your code of C2, potentially dangerous, for the all insulated pendant lamp fiasco still dragging on, can we assume this will be a C1+++? Immediate remedy? That is going to go down like a lead balloon to customers who have been ripped off and forced wrongly to have a metal fusebox installed in the last year or so which would have given years of service  just to accommodate the new device. What is going to happen? the old box handed to the local rag and bone man on Sunday morning when he rings his bell. And then another grand handed over for another box fitted. 


    Public consultation? dont your friends on the committee read these topics? I see you are already using the catch all term "fire". Suddenly we will see a report of XXXXs of fires which we have not heard of before.


    As a special treat, we will be invited to purchase "IET guide to AFDDs" 1st of many editions, £200, discount for cash.


    Regards, UKPN
  • A couple of weeks ago I was doing a job for a former fireman, he said they rarely saw a fuse board fire, I said that’s odd because the London Fire Brigade were supposed to be one of the main proponents of changing the Electrical Regulations to make non-combustible consumer units compulsory in domestic properties.


    He laughed.
  • I am prepared to believe that AFDDs will spot some faults that other devices wouldn't disconnect. I am also aware that they'd likely provide some protection downstream of the fixed wiring too - say to all those £5 extension leads run behind the bed and dodgy USB chargers.


    I am very dubious about the cost/benefit ratio however. I suspect the number of fires started by arcing alone (rather than say by resistive heating) is relatively small - and given the BILLIONS of pounds that would be needed to upgrade UK homes alone (never mind other installations) (say 30 million homes @ £2,0000 a pop = £60,000,000,000). My gut feel is that the money could be better spent elsewhere.


    I'm also very uneasy of dictating a single solution to the arcing problem (if there is one) - I can imagine several situations - e.g. wiring in steel conduit with metalclad accessories, supplying steel cased fixed equipment where the chances of an arc starting a fire in the fabric of the building must already be vanishingly small - yet such alternative approaches don't seem to have been considered.


    Then there's the law of unintended consequences ... at £2,000+ CU replacement is going to be discouraged economically - so more installations will carry on for longer with dodgy installations. The usual accessibility requirement for the actuating levers of devices to be between 1350-1450mm above floor level means we won't be able to use Euro style multi-row CUs, so we'll need a large amount of horizontal space for a CU (probably two or more enclosures side-by-side) for these multi-module devices. And as the technology seems to require one device per final circuit, there'll obviously there'll be an economic incentive to minimise the number of final circuits - with possible safety compromises as a result (e.g. loss of lighting over a wider area/stairs due to a single fault).


    Were AFDDs say £5 a pop extra (over say an RCBO), were a single module wide, could be retrofitted into existing CUs, and could be shown to be reasonably resistant to nuisance tripping, and were only demanded where sensible alternatives weren't adopted, I'd probably be entirely happy with the regs to demand them. I don't think that time has arrived though.


      - Andy.
  • The amendment says don’t fit AFDD on domestic lighting circuits.
  • Sparkingchip:

    The amendment says don’t fit AFDD on domestic lighting circuits.


    Someone missed the opportunity to mandate emergency lighting in domestics there ?


  • Presumably, a 10 way CU from Wylex costs about £2000. This is a joke. A normal board with 2 RCDs costs around £100-120. The price has been multiplied by 20 times with the stroke of a pen! They also consume power at all times, lets say 1W, so an additional 10W load (10 way board) uses about 10 x 10000 kWh/year = 100 kWhr/year, about £17 too. This alleged fire protection is quite expensive, particularly as there is no evidence it will reduce fires at all. It will only cost £60 billion + 30 GWhr per year. Fantastic!