Ceiling downligts replacement.

[EFLImpudence]

As I keep saying, maybe I'm missing something - but I read the regulations as saying that the 'third option' does not exist - i.e. protection against electric shock has to be provided by either an earthed metal casing or by double/reinforced insulation.

I suppose such rules do not apply to things from which it is impossible to receive a shock.

I'm obviously not saying that one should even think of 'earthing' a non-conductive casing (c.f. a plastic water pipe), but my reading (perhaps/probably wrong) suggests that if there is not a metal casing to earth, the only other available 'allowable' option is for it to be Class II.

Plastic light switch on plastic pattress - what would be the point of actually making it a compliant Class 2 item?

Do you therefore believe that there is some acceptable option (regs-wise) which is neither Class I nor Class II?

That from which it is impossible to contact the 230V ?

You seem to feel that a 'plastic (or wooden, or whatever) box' affords adequate protection, but does it not have to qualify as "double/reinforced" insulation (i.e. 'Class II') in order for it to be 'allowable'?

Obviously not.

I imagine you would not accept a box made out of paper or cardboard, and that you would not accept a covering of PVC tape. What about a thin/flimsy plastic box? Where are you drawing your line?

I don't know, other than there must be rules for the manufacture of such things.

 

[JohnW2]

I suppose such rules do not apply to things from which it is impossible to receive a shock.

Indeed - but, as I said, one has to decide what is required to make it "impossible to receive a shock" - live parts from which a person was only protected by a very flimsy plastic box/enclosure would presumably not qualify as making a shock 'impossible' - that's surely why the insulation of single-insulated Class II items has to be "reinforced" isn't it?

Plastic light switch on plastic pattress - what would be the point of actually making it a compliant Class 2 item?

Given that plastic light switches and pattresses are made of a material which is seemingly far more 'reinforced' (resistant to mechanical damage) than is many a Class II item, I would think that they probably already are "compliant Class II items", in which case the question is why they are not marked as such.

That from which it is impossible to contact the 230V ?

As above, what would be deemed to render contact "impossible"? Paper, cardboard, PVC tape or a thin/flimsy plastic box would presumably not be considered adequate to achieve that - which is why they would not be acceptable as 'the insulation' of a Class II item.

In fact, making it "impossible to contact 230V" is surely the whole point of the double/reinforced insulation required of a Class II item - so if an item is manufactured in such a way as to create that "impossibility", then it surely would qualify as Class II, wouldn't it?

Kind Regards, John

 

[EFLImpudence]

I don't know the answers to your questions Ber John, other than to say light switches do not have cable restraint so are not class 2.

 

[JohnW2]

I don't know the answers to your questions Ber John, other than to say light switches do not have cable restraint so are not class 2.

Interesting. Is cable restraint a requirement of a Class II item?

I suppose one of the problems is that, although we all talk a lot about Class II items of equipment, I'm not sure that any of us actually know what regulations/requirements apply to such items. All of what most of us know about "Class II" relates to what (little) is said in BS7671, and that relates essentially to the wiring of an installation, not the items of equipment themselves.

Kind Regards, John

 

[ericmark]

Interesting on earthing class II, I was asked to PAT test a mag mount drill, the mag mount requires an earth, the drill is class II but the drill is clamped in the mag mount so is earthed as a result.

I do see the problem with a metal class I drill being left on a metal work bench where some one has done some welding and the earth wire has burnt out as a result, and could also cause the live wires to connect to earth as a result. However if the drill has the ability to be clamped in a stand, then the manufacturer must allow for the drill to be earthed as a result.

So if there is metal in walls or celling and something is mounted in the wall or ceiling then one must allow for something else also mounted in the walls or ceiling to be earthed.