LED light fitting

[ban-all-sheds]

The enclosure was and remains an exposed conductive part (or exposed-conductive-part, if the hyphens are important - or did you mean to write Exposed Conductive Part?). I think that is basically my point.

But it isn't.

Assuming the DI designation is correct, then by definition the enclosure is not an exposed-conductive-part.

the product is marked double insulated. the product is not double-insulated. Is it? .... is it?

The manufacturer says it is. See post#15 for what you should do if you have cause to doubt them.

 

[SparkyTris]

carry out the rectification

I didn't use any diodes in my mod...?

I will see if Trading Standards are interested in this.

Harking back to post nr.3, where B-A-S implied that I have made the light more dangerous.
I have taken some pains to illustrate the hard facts of this case. in light of these, have I actually made the light more dangerous or more safe?

 

[seasickstevie]

... doesn't stop us assiduously earthing the cases of - for example, ... , DVD players....

You might struggle to purchase a class 1 DVD player.

 

[seasickstevie]

... presented to the installer with L and N singles in about 1mm2 that come straight out the back of the base ...

I think you'll find rather than your standard '1mm² singles' (they maybe more likely 0.75 or something), they are insulated in fact to a pretty tough standard. There is a technical classification for it I believe; others may be able to quote it.

 

[JohnW2]

Double Insulated means that there are (at least) 2 insulating layers between the user and the juice.

... or one layer of "reinforced insulation, whatever that might be (I've never seen a definition). I would say that the majority of Class II items I've seen (i.e. marked with the 'DI' symbol) have had only one layer of (I can but presume 'reinforced') insulation between some live parts and the outside world.

Kind Regards, John

 

[SparkyTris]

True. I had noticed that the insulation is not 1 layer of pvc, it is something (slightly) tougher indeed. the DI classification may well be defensible.
My main justification for earthing the backplate was the little HF LED driver module. I have seen enough of them fail catastrophically to realise they are a weak point.

 

[seasickstevie]

I've seen halogen-type SMPSs ('transformers') fail "catastrophically" (although that's a rather strong description), but the load that an LED driver handles, I wouldn't expect damage of such a magnitude.

 

[JohnW2]

True. I had noticed that the insulation is not 1 layer of pvc, it is something (slightly) tougher indeed. the DI classification may well be defensible.

Indeed. As I said, a high proportion of DI-marked (i.e. 'Class II') items appear to have only one layer of insulation, at least in relation to some live parts, so I can but assume that it has somehow been decided/determined that the material of the single layer qualifies as "reinforced" - but, as I also said, I've yet to see a definition!

Kind Regards, John

 

[JohnW2]

I've seen halogen-type SMPSs ('transformers') fail "catastrophically" (although that's a rather strong description), but the load that an LED driver handles, I wouldn't expect damage of such a magnitude.

It's obviously the current which flows during fault conditions which determines how 'catastrophic' ('dramatic') is the time/moment of failure, but that current can be orders of magnitude higher than the current which would flow during 'normal service' (i.e. determined primarily by the intended load).

A power supply might be such that only a handful of mA flows during 'normal service', but if, for whatever reason, it develops an L-N short in the 230V circuitry, hundreds of amps could flow (for a very brief time).

Kind Regards, John