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AFDDs AMD 2

John Peckham
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?


  • 0
    AJJewsbury:
    So then we discussed the next stage. I pointed out that the deadline is 28 March 2022, 'cos after that, the brand new shiny CU is obsolete!

    Regs change dates are usually for the design rather than installation phase - so "design" the CU replacement now and install it whenever you like!


       - Andy.


    The intro to 18th Edition does indeed refer to Design, but interestingly the intro to AMD2 refers to erection.

    So the proposed timeline seems to be:



    • publish 28th March 2022 

    • compulsory from 28th March 2023 for erection stage

    8601cf656a7bf1c1cc85ca7152739515-original-18th-amd2-intro.jpg

  • 0
    About 10 years ago, I carried out an "EICR" on a 2nd floor flat, because the casing of plastic CU, mounted at high level on the stairway was burnt with a hole in it. The position of the CU on an escape route (stairway), then lead to close monitoring; had the CU been unseen in a cupboard, the damage could have taken longer tto detect with more risk. The CU was changed but again with a plastic one, since there was no requirement for a metal one at that time. 


    The Americans (and Canadians), have recognised for many years, the danger of arcs - the reason why there is now mandatory regulation for their arc-fault circuit interrupter (AFCI or AFDD) in homes. I think they will eventualy come down in price in the UK, and also become mandatory in homes etc. The insurance companies will also probably drive this. At present, consumers will probably baulk at the difference in cost.  


    BTW where is Geoff Blackwell ........... a valued contributor?


    Jaymack
  • 0
    -2400-:
    AJJewsbury:
    So then we discussed the next stage. I pointed out that the deadline is 28 March 2022, 'cos after that, the brand new shiny CU is obsolete!

    Regs change dates are usually for the design rather than installation phase - so "design" the CU replacement now and install it whenever you like!


       - Andy.


    The intro to 18th Edition does indeed refer to Design, but interestingly the intro to AMD2 refers to erection.

    So the proposed timeline seems to be:



    • publish 28th March 2022 

    • compulsory from 28th March 2023 for erection stage

    8601cf656a7bf1c1cc85ca7152739515-original-18th-amd2-intro.jpg

     


    Humm - I can imagine that not going down well with some of the larger projects...


      - Andy.


  • 0
    There is of course the issue of suitable products not being available. A couple of year ago I set about designing an electrical installation for a small rural church near Ross-on-Wye and spoke to Wylex about AFDD.


    The Wylex AFDD cannot be used in their three-phase distribution boards as they do not have guards to separate the phases on the base of them. The architects were insisting there had to be E7 storage heaters and three phase had to be available should catering equipment be installed at a later date in the vestry. I was heading in the direction of having two three-phase boards and six single-phase boards in a very small church and the cost of AFDD was very high, the architects were saying that of course AFDD would be required, but when costs were mentioned they didn't have the funds to pay for the simplest of installations and started talking about applying for Lottery funding.


    What's different now, anything? Are three-phase AFDD now available or single-phase AFDD that can be used in a three-phase distribution board?


    Andy Betteridge.
  • 0
    I realise that the proposed regulation says single-phase circuits, but the circuit could originate in a three-phase distribution board and as far as I am aware it definitely cannot be done by installing single-phase AFDD in an existing or new Wylex three-phase board.


    Is there any manufacturer that makes a suitable AFDD for commercial installations that doesn’t require the installation of domestic consumer units to install AFDD?


    Andy Betteridge.
  • 0
    I have done a bit of digging around.


    It seems that BS EN 62606 has been prepared by CENELEC at the request of the European Commission. BS 7671 is obliged to follow suit.


    The scope of BS EN 62606 includes:

    This International Standard applies to arc fault detection devices (AFDD) for household and similar uses in a.c. circuits.


    The classification of AFDDs currently extends only to 2-pole devices. 3- and 4-pole devices are under consideration. It seems that nobody makes 3-phase AFDDs.


    The Eaton offering, for example requires a completely different busbar set up - details here.


    They also make a type B board, but it isn't clear whether 3-phase outgoing devices can be fitted - details here.


    Retro-fitting clearly isn't an option.
  • 0
    I could make an extremely rude remark about the European Commission. They are nothing to do with us, and we do have ability to change Cenelec stuff if we don't like it.
  • 0
    I was contemplating the enormous ballsache of changing the DB at the origin in my garage when it occurred to me that AFDD there simply isn't necessary. The wiring is singles in metal conduit. The standard of workmanship is first rate - I know 'cos I did it myself. ? I cannot envisage how the fixed wiring could be damaged so that it gave rise to an arc fault.


    So what is the risk?


    I suppose that T&E stuffed under floorboards is at risk of rodent damage.


    Then there is the poor workmanship of Bodgit & Scarper, but could they be relied upon to install AFDD correctly?


    Lastly, there are the flexes on appliances which are left plugged in all the time. We have all seen plugs with the sheath pared back too far and nothing clamped under the cord grip, but with moulded plugs, they should be a thing of the past. Then there are flexes clamped in doors with not a thought given to any damage which may occur.


    So it seems to me that AFDDs are a solution for a problem which should not exist if people treated their electrical equipment with proper respect.
  • 0
    Chris Pearson:

    So what is the risk?

    AFDDs seem to be targeted mainly at the products of white goods manufacturers, who seem unable to build anything which doesn't go up in smoke.
  • 0
    Just how can An AFDD like this be installed in an UK tin can consumer unit?


    There is only one viable product without a redesign of consumer units, it should be noted that it is also a 10 mA RCBO, there’s a who different approach to designing electrical installations in the rest of Europe, trying to adopt just parts of design doesn’t mean that we will be able to source devices from Europe, they will have to be UK specific.

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