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it says that class 2 has a double layer of insulation between the load and the user
Am I right in thinking all class 1s are metal outer-casing?
Wiring a LED AC floodlight up with no earth wire
- Thread starter BobyBoy230
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Am I right in thinking all class 1s are metal outer-casing?
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Have done a continuity test and there are 3 wire to the Euro plug cable
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It doesn't follow. All class II products have a square in a square symbol, everything else is class I.
Which leads me to the question I have asked umpteen times, without receiving anything close to an answer ...
We do, as you say, tend to say that anything without a 'double-insulated' symbol is, by default, Class I. However, as I understand it, the definition of Class I requires that it provides protection against electric shock by means of earthed metal. So, if it is not Class II ('bureaucratically', since it does not bear the appropriate marking), but it cannot be Class I (since it has no metal to earth), then "what is it'?
Kind Regards, John
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We don't know.
Quite so - but it does make me question the view that anything which does not bear a 'double insulated' symbol has to be Class I - particularly if, as I said, the nature of the item is such that it cannot, electrically, be Class I!
Kind Regards, John
Yes, I don't necessarily agree with that.
There are:
class 2 items which must not be earthed (I know you don't like that),
class 1 items which must be earthed, and
items which cannot be earthed - plastic items, e.g. plastic switches.
What about metal light switches? Are they class 1?
One cannot even say class 1 and 2 only applies to appliances because the same three categories apply.
My Henry vacuum cleaner is marked class 2 but in the third category.
There are:
class 2 items which must not be earthed (I know you don't like that),
class 1 items which must be earthed, and
items which cannot be earthed - plastic items, e.g. plastic switches.
What about metal light switches? Are they class 1?
One cannot even say class 1 and 2 only applies to appliances because the same three categories apply.
My Henry vacuum cleaner is marked class 2 but in the third category.
Exactly - and (forgetting my personal views about the Class II ones!), it is the third (I would think pretty common) group that we're talking about - and, although they don't (by your definition of three groups) have a DI symbol, it would seem totally daft (as well as probably being contrary to definitions) to call them "Class I".
I think there are a few which are Class II, and are marked as such. However, forgetting those, they presumably are Class I, aren't they - since they are using earthed metal to provide protection from electric shock?
I think the same is true of many items marked as Class II. True 'double insulation' seems relatively uncommon, many/most Class II items relying on 'reinforced', rather than 'double' insulation to achieve their Class II status. That being the case, one of your 'third category' would only not qualify for Class II status if their insulation was deemed to not be sufficiently 'reinforced'.
I suppose that leads me back to my usual question, of whether a 'third category' (nothing to earth) item is actually 'allowed' if it does not have adequately 'reinforced' insulation to qualify as Class II. On the face of it, such an item probably does not provide adequate protection against electric shock - which, the in absence of an earthable metal casing, seemingly has to be provide by adequate double/reinforced insulation.
Kind Regards, John
Really. I was not aware.
Yes, but just as (most) plastic switches are not marked as class 2, are the metal ones marked as class 1 or do they actually state they must be earthed - or is it just obvious.
Does the plastic body count as the second insulation?
Again, the body? Drills when class 2 do not appear to have more than ordinary flex.
No everything else is not class 2. However it could be class 0 (in some countries).
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At least write something that makes some sense, or just don't bother.
I may be wrong, but I think I've seen some which are essentially plastic switches with a metal 'cover' over them (and something clever to get around the potential 'screws' problem).
There is no Class I 'marking', is there? I'm sure that the instructions which come with them always say that they must be earthed, and maybe some actually say that on the switc h?
You mean the body of the switch mechanism? If so, not all of the 'live parts' are fully contained within that plastic (because of the terminals and terminal screws).
Drills are surely a bit different - not really in your 'third category', since they may have at least some exposed metal parts (e.g. chuck, or bits of chuck) which 'could' be earthed. Class II drills presumably will, in part, be truly 'double insulated', even though their casing will usually be plastic, and hence probably "reinforced insulation".
What do you mean by "do not appear to have more than ordinary flex"? Do you just mean 2-core?
Kind Regards, John
If you don't know what I am talking about admit it. There is no reason to be rude and insulting.
Read this and learn. Class 0 is something without double insulation and without earthing. For many years illegal in the UK except for Christmas tree light strings, though they now have double insulated cables.
Class 0 equipment can still be found in many developing countries.
John,
No, I'm asking if the plastic bodies of e.g. vacuum cleaners and drills are the second part of double insulation.
No, I'm asking if the plastic bodies of e.g. vacuum cleaners and drills are the second part of double insulation.
I don't think that is the "not making sense" that Detlef was referring to - I think it more likely that he was referring to ...
Maybe you didn't read what Detlef and/or yourself had written?
Kind Regards, John
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