18TH EDITION AMD 2

Can only access part 2 of it so far . 


does anybody have the actual links for the separate parts ? BSI online chat help was anything but helpful

I seem to have been given a new identity here too. was this part of the big changeover a few years ago ?

try https://standardsdevelopment.bsigroup.com/committees/50001574


to see a list of what JPEL/64 is working on currently - near the top should be the AMD docs.


Yes the new forum software is a bit less configurable than the old. If you want you can set a 'screen name' so you do nt reveal who you are to the wider world.

Oh, and signatures fell off at the last 'upgrade' so you need to type them out each time,

regards Mike

Humm, is there no indication of the changes?

 

I feel sorry for all the Landlords that are going to be forced into this by the new renting rules ( I think the law is a good one for safety of tenants) who are now going to be forced, with no choice but to spend £2k on a board that meets the 18th Amd 2

 I don't think they will - at least not for the present - as that Law doesn't refer to the current version of BS 7671, but specifically to the vanilla version of the 18th (BS 7671:2018) - later versions of BS 7671 won't apply under that law unless parliament specifically changes the wording (and apparently that's deliberate - they don't like the idea of "others" (e.g. the IET/BSI) being able, in effect, to change the meaning of the law. Judging by the ESQCR which still refers to the 16th Ed, parliament don't seem that bothered/able to keep things up to date.

 

Presumably it will be similar to when RCDs came in

Not entirely - when RCDs (or ELCBs) first came (and they were of course relatively expensive) you could have a high rated unit (63A/80A/100A) that covered an entire installation or at least a decent chunk of it - so the costs could be manageable (we still have split CUs). AFDDs seem to be different and for some reason seem not to scale up in the same way as RCDs do - AFAIK you simply can't get an AFDD rated much above 40A (not even in 115V parts of the world where they'd need circuits of twice the rating of ours for the same effect) - so installation-wide protection is required, there seems little alternative to a separate AFDD on each and every final circuit - which of course gets very expensive very quickly.


   - Andy.

This comes in the 28th March and the landlords need to have everything sorted out by the 1st April, so the amendment is not an issue for landlords as they should have everything done and dusted.

Anyone any good at sums.


If an AFDD costs £200 how much for circuit protection when installing a 48 way 3 phase DB that does not supply any 3 phase circuits or crane lifting magnets?

 

As they only work on sustained arc faults not sparking faults or I squared R heating faults, and we know it is hard to strike and maintain a sustained arc at 230V why are these devices require?


where is the safety case for fitting AFDDs?

As far as I can see, no supporters of AFDD here, so how do we respond with maximum effect?

I must admit I am concerned by the introduction of AFDDs . There is no agreed means to test them and very little evidence that they actually do much to save lives. It is not like the RCD where  the detail of how it works is very much public domain, there is a clear class of fault for which they reduce the danger and there are predefined tests and third party test kit so you can verify your chint RCD on your meggar tester.


I detect a product seeking a solution - where are the tables and graphs showing the big fall in the number of fires and electrocutions since they came in for the USA where they have now had them for a while ? I'm sure if they did anything, there would be evidence. Maybe like our own part P, there isn't any technical justifiaction, it just feels good, and that is the direction of the politics.


I know  Paul Skyme was involved in a project to to and look at one E5 youtube video  and certainly if you have an installation with a micrometer controlled contact gap in it, the eaton AFDD will find it. While this is some fascinating engineering, I'm not convinced that it is a realistic representation of any kind of fault found in real life.

Yes, I think the Eaton demo kit is nonsense.  it'd be interesting to know what the electrode faces on the micrometer setup are made from, they are not copper.  IEC 62606 tests (for AFDD proving) uses one carbon and one copper electrode in a similar jig.  Obviously, this creates an arc-lamp like situation but fails to prove anything other than AFDDs detect consistent (stable) arcing.


Other tests involve carbon too, with the exception of where a parallel fault is created via guilloteening a cable but I have never seen this test actually done despite it being the most realistic of the various IEC 62606 tests.


I too have not seen evidence that 230V arcing is a significant cause of electrical fires.  HRCs are a much more believable fire causing fault mode.


If its the E5 video that I have seen, wasn't the conclusion "Yes, it's a good toy..."?  I'm not sure what that conclusion meant...