AM2 changes on sources for SELV and PELV

It all depends on how those SMPSUs are made.

This has been complicated by the fact that a new standard BS EN 62368-1, which has now replaced BS EN 60950-1, does not recognise SELV and PELV especially the behaviour under single-fault conditions. The alternative provisions do not fully align with BS EN 61140 requirements for SELV and PELV. The second consideration, is that not all electronic equipment standards recognise the need to maintain the lowered SELV/PELV voltages in certain Part 7 locations, including under single fault conditions.

Now, what's really confusing is that a particular product may meet the requirements for SELV and PELV (and even the lower voltage requirements), but there is now no way to prove that by complying with certain (but not all) product standards (some other product standards cross-refer to BS EN 62368-1).

Sadly, the onus is on the installer to check the product meets the requirements (of BS 7671), but of course some of these devices are "plug and play" and a consumer may well get hold of their own (non-compliant) replacement.

My assumption was that normal lighting 'transformers' (including electronic ones) would provide isolation according (i) or (ii) - and that (iv) was only for some weird and wonderful contraptions that didn't provide conventional isolation from the mains (the note talks about test equipment).

Looking at a couple of data sheets though I can't see BS EN 61558 obviously mentioned though - maybe it's implied via more specific product standards or may be I'm being overly optimistic...

   - Andy.

You cannot test compliance into a product, it comes from the design. Why we have adopted this standard is ridiculous, is there NO ONE left who can actually read proposed standards and see that they are useful, and in compliance with all the existing ones? I am currently working on another problem, but the same kind of thing has happened, NO ONE has actually understood what is in a draft!

AJJewsbury said:

My assumption was that normal lighting 'transformers' (including electronic ones) would provide isolation according (i) or (ii) - and that (iv) was only for some weird and wonderful contraptions that didn't provide conventional isolation from the mains (the note talks about test equipment).

Switching type converters are becoming the norm for these "transformers" particularly LED drivers. It depends on how the converter is made.

David Stone said:

is there NO ONE left who can actually read proposed standards and see that they are useful

Who is the individual, or department, who would actually "police" this in a reasonable timescale?

The enormous standards making machine Graham, if a standard is referenced in any other standard (and the web is ridiculous as you know well) then the proposed change should be considered by them. In some ways JPEL/64 does well in this regards, but many others don't, and I am not sure that enough weight is given to objections either. It simply needs someone to cross reference everything with a computer, BS7671 is quite good in this respect.

BS 7671 doesn't currently make reference to BS EN 62368-1 for electrical safety, only "along with" relevant parts of BS EN 61558 for EMC purposes (i.e. in that case, a device to the product standard, incorporating a transformer to EN 61558).

Interestingly, this particular issue came to light as part of international standardization work to implement power over Ethernet in the installation standards, so before BS 7671 references it for safety, it has been checked.

Therefore the system you propose is in place and working.

To be fair to the international committees responsible for BS EN 62368 (which replaces BS EN 60950), they did publicise the change of approach when they drafted the new standard ... and therefore I think the disconnect is either:

(a) not addressing (or not appreciating at the time) all of the relevant use-cases, particularly of products to BS EN 62368-3.

(b) the complexity of the approach in BS EN 62368 in terms of "energy levels" of touch voltage and touch current meaning it is difficult to understand and draw parallels with IEC 61140, and I think this is the key issue - too time-consuming to look into too deeply for many, and on the surface it looks OK, so ...?

David Stone said:

It simply needs someone to cross reference everything with a computer

I don't think that would have highlighted this issue. It requires detailed technical knowledge of IEC 61140, IEC 62368 and IEC 60950, along with an appreciation of special installation conditions for some applications and how this affects electric shock risk according to IEC 60479 series.

David Stone said:

You cannot test compliance into a product,

Apologies for taking a step back in the discussion. I agree with this statement, which is why I used the word "prove" not "test" (although "demonstrate conformity" would have been a better statement).

That can be done by a combination of inspections, tests, checking design, and checking relevant status of components procured (and later, production substitution controls). Product standards account for these elements by, for particular sets of requirements, using "conformity shall be demonstrated by ..." type statements.

I too have been searching to an answer to this problem.  In practical terms, does anyone know of an "off the shelf" product that will satisfy 701.414.3 

Are the downlights higher than 2.25 Metres?

Z.