Do you not think enclosed in a plastic box is "supplementary insulation"?
Connecting a LED security light.
- Thread starter johnFbrown
- Start date
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Not if there are uninsulated live parts within the box - it would then surely be "basic" (and the only) insulation.
If everything within the box were itself insulated (e.g. single-core, single-insulated wires/cables), the the box would then constitute 'supplementary' insulation, making the live parts 'double insulated'. However, if there were uninsulated live parts (e.g. terminal screws) within the box, I don't see how you could call the box 'supplementary', since it would be the only insulation.
Kind Regards, John
I don't think that is the criterion.
Is it not that, when assembled, ONE fault cannot result in a shock risk?
After all, many things, such as lighting power supplies and hand tools which ARE Class II, only have (normal) screw terminals which are covered by screwed down plastic covers; the cable being restrained by a clamp.
If a live conductor comes out of its terminal, it will still not cause the object to become live and cause a shock risk.
All cables have to be fitted to the appliances somehow so the terminals are bound to be accessible at some time.
Surely, it is when in normal use that counts.
Is it not that, when assembled, ONE fault cannot result in a shock risk?
After all, many things, such as lighting power supplies and hand tools which ARE Class II, only have (normal) screw terminals which are covered by screwed down plastic covers; the cable being restrained by a clamp.
If a live conductor comes out of its terminal, it will still not cause the object to become live and cause a shock risk.
All cables have to be fitted to the appliances somehow so the terminals are bound to be accessible at some time.
Surely, it is when in normal use that counts.
That's not my understanding/interpretation, and we've discussed this here before.
I think that the assumption is that, in the sort of situation you described (just a single plastic cover between live parts and the outside world), to qualify as Class II the material of that cover would have to qualify as "reinforced insulation", whatever that might mean.
Is that what others believe?
Kind Regards, John
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..but you, yourself pointed out, it says double insulated OR reinforced.
Exactly (even though you kept telling me that the Part 2 definitions don't mention reinforced insulation!) - which is why I think we have to assume that, in the case of products such as you mentioned, which have just one layer of 'plastic cover' between live parts and the user, that plastic must somehow qualify as 'reinforced insulation' for it to be Class II.
I haven't a clue as to what qualifies as "reinforced insulation". Maybe stillp could help?
Kind REgards, John
Ah, I see.
You don't think the connector blocks are insulated because the screws are accessible, albeit not with a finger, once one layer of insulation has been removed by the use of a tool.
I do not know if that is considered correct.
Would you, therefore, not class a disused live conductor with a connector block on the end as insulated and/ or isolated?
You don't think the connector blocks are insulated because the screws are accessible, albeit not with a finger, once one layer of insulation has been removed by the use of a tool.
I do not know if that is considered correct.
Would you, therefore, not class a disused live conductor with a connector block on the end as insulated and/ or isolated?
I don't know. In any event, it doesn't have to be a connector block in the sense you mean - it could be screw terminals with screw heads that one could undoubtedly touch with a finger (even if it took a bit of effort!)
That's really a variant of the question I have been asking (reg-wise, not in terms of common sense). As above, I'm not sure as to whether the screws of connector blocks would be regard as 'exposed' - although, as I said, I think there are plenty of other cases in which terminal screws (or other live parts) are definitely 'touchable', but only seem to be insulated/isolated by a thin plastic 'cover' - which may or may not qualify as reinforced insulation. If they were regarded as 'touchable' then being separated from the user by just one layer of non-reinforced plastic would presumably be no more acceptable than would be an exposed insulated-but-not-sheathed conductor?
What about plastic CUs? Quite apart from any parts at line potential that may be exposed, I don't think the regs distinguish between L & N 'live' parts - and once the plastic cover is off, the neutral bar is inevitably exposed. Do I therefore take it that their covers are deemed to be 'reinforced'?
Kind Regards, John
That's a good point.
Are they considered Class II?
If not, then they would seem to be the same as you think the light is.
These things are similar and are Class II.
I don't know.
... but what is that 'same'? They can't be Class I, so if they're not Class II, is there something else they are 'allowed' to be?
Bear in mind that I am asking questions, not attempting to give answers - it's something I've never really understood very well.
Kind Regards, John
Indeed, but look what's just beneath the (thin and brittle, hardly 'reinforced') plastic cover of these sort of things (this all marked as Class II):
Kind Regards, John
Yes, that's what I meant. I don't know the answer.
Nor do I - that's why I asked the question!
I presume that the manufacturers (Aurora in the case of my photo) believe that they are Class II, since they are marked as such.
KInd Regards, John
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