No Earth Wire in New Fitting And Also

[suffolkoff]

Hi everyone,
Wondering if anyone can help? I have no Earth wire in the new light fitting I'm trying to put up, which I suppose is fine because it must be double insulated? (It has the double square - please see photo with Maison sticker).
I thought this would be an easy job, but there are a million wires coming out of the ceiling...Can I put the Earth wire which is currently attached to the old light fitting (which is still up) into one of the connection blocks for another Earth that is already there?
Then should I just put the live and neutral wires from the new fitting into where the wires from the old fitting are?

Thanks!

 

[securespark]

Well, I can see that your "new" light is "old" in that it is second hand. You should use the connector that came with the fitting when new. They are a PIA, but you need to ensure separation between the incoming cables and the fitting. Just ensure the earths are all in a block together and do not electrically come into contact with the fitting.

 

[suffolkoff]

Yes the "new" fitting is second hand. Sorry I'm a rookie here. I know, that means I should probably get an electrician in but I was hoping it could be straightforward.

 

[plugwash]

The problem with class 2 "double insulated" metal light fittings is that while they may well meet class 2 insulation standards when installed exactly in accordance with the manufacturers instructions and fed by a single cable, in practice they are very often wired in ways that violate the class 2 insulation standards.

To maintain class 2 insulation standards on such a fitting the incoming cable must remain sheathed and protected from abrasion until it passes into a terminal enclosure and all connections must be made inside that terminal enclosure. In practice what that means is that you need to bring a single cable to the light and that cable must have enough slack. Often this means fitting a maintainance free junction box in the void above the fitting to deal with multiple cables and/or cables that have insufficient slack.

The fitting you have looks like it has had it's terminal enclosure butchered by the previous owner. So re-using it doesn't look like an option. Finding a replacement fully enclosed terminal enclosure that is small enough to fit inside the fitting is likely to be difficult.

The other option is to modify the fitting to attach earth wires to the exposed metal parts and make it class 1, but again this may be easier said than done.

 

[suffolkoff]

Thank you so much for your advice! I really appreciate it and learned so much!

 

[JohnW2]

The problem with class 2 "double insulated" metal light fittings is that while they may well meet class 2 insulation standards when installed exactly in accordance with the manufacturers instructions and fed by a single cable, in practice they are very often wired in ways that violate the class 2 insulation standards.

Indeed.

However, does the fact that it has been manufactured such that it can be regarded and used as Class II if it is "installed exactly in accordance with the manufacturers instructions and fed by a single cable" preclude using it as Class I - i.e. by finding a way of connecting the CPC ('earth') (that the OP does have) to the exposed metalwork of the fitting (in which case the 'double insulation' issues within it would cease to exist)?

Kind Regards, John

 

[EFLImpudence]

Isn't that what Plugwash said?

I think the point is, as has been said many times, that Class II is regarded as 'safer' - otherwise there would be no reason to make Class II items - therefore changing it to Class I when avoidable would be silly.

Why do you have such a problem with Class II items when it is obvious that the fewer earthed metal bits there are around; the better?
You wouldn't fit a piece of earthed metal to the outside of a completely plastic item just for the sake of it.

 

[JohnW2]

Isn't that what Plugwash said?

It is - I confess that I somehow 'missed' ('glanced over with noticing') the last sentence of plugwash's post - my apologies.

I think the point is, as has been said many times, that Class II is regarded as 'safer' - otherwise there would be no reason to make Class II items - therefore changing it to Class I when avoidable would be silly.

I don't think it's particularly obvious that Class II is necessarily 'safer' in all situations, since there are pros and cons. For example, whilst, in most cases, Class II is arguably 'safer' so long as the item concerned remains intact, if it suffers mechanical damage, then Class I may be 'safer'.

As I often say, what confuses a lot of these discussion is that a high proportion of items which bear Class II markings do not have any exposed-conductive parts - which results in the question which I frequently ask but to which no-one (including yourself) seems to know the answer! The point, of course, is that these discussions are only relevant to Class II items with exposed-c-ps - which, at least in my experience, are relatively rare (the few I can think of in my house are mainly power tools).

Why do you have such a problem with Class II items when it is obvious that the fewer earthed metal bits there are around; the better?

I don't 'have a problem' with it and, as you must know, I often point out to people that any 'unnecessarily earthed touchable metal' presents a theoretical increase in the risk of electric shock - although, in practical terms, the magnitude of that theoretical risk is usually incredibly small.

Personally, I do think that it is a incredibly small risk - particularly in relation to electrical items (and very particularly when they are attached to a ceiling). If I were truly concerned about the level of increased risk of electric shock resulting from there being 'unnecessarily earthed touchable metal' in my house, I would be far far more concerned about all the earthed (and large area) radiators and pipework throughout my house (some of which I probably touch every day, quite possibly whilst also touching other things) than about the small casing of a light fitting on a ceiling - and would therefore be taking steps to electrically isolate from earth as much as possible of the touchable metal parts of my CH and plumbing systems etc .... but I don't feel the need to do that!

Kind Regards, John

 

[plugwash]

As I often say, what confuses a lot of these discussion is that a high proportion of items which bear Class II markings do not have any exposed-conductive parts - which results in the question which I frequently ask but to which no-one (including yourself) seems to know the answer! The point, of course, is that these discussions are only relevant to Class II items with exposed-c-ps - which, at least in my experience, are relatively rare (the few I can think of in my house are mainly power tools).

Plenty of AV/hifi/IT gear is metal cased class 2 and even the plastic-cased stuff has connectors with touchable metal connected to it's internal DC rails.

But that is not what this thread is about, this is about the light fittings that are sold as class 2, but end up as class 0 after the installers have finished with them.

 

[JohnW2]

Plenty of AV/hifi/IT gear is metal cased class 2 ...

Some certainly is. I merely said that, at least in terms of what I own and have seen, a high proportion of the items bearing Class II markings has no exposed-c-ps.

.... and even the plastic-cased stuff has connectors with touchable metal connected to it's internal DC rails.

Is that not a rather different issue, related to the electrical isolation and separation between the mains input and the internal DC circuitry? In such equipment, is there really always 'double or re-inforced insulation', internally, between the LV and ELV stuff?

But that is not what this thread is about, this is about the light fittings that are sold as class 2, but end up as class 0 after the installers have finished with them.

I agree. Due to my unfortunately not having noticed your comment, I merely repeated your comment about the possibility of using the Class II fitting as Class I, whereupon EFLI took me up on that general point.

... so, getting back on topic, do you agree with EFLI that it would be bad (and 'silly') to earth the metal of the OPs fitting (hence use it as Class I) and that if one did that, one would make it appreciably 'less safe'?

Kind Regards, John

 

[EFLImpudence]

... so, getting back on topic, do you agree with EFLI that it would be bad (and 'silly') to earth the metal of the OPs fitting (hence use it as Class I) and that if one did that, one would make it appreciably 'less safe'?

I said it would be silly if avoidable.

If the OP has connectors in the ceiling cup then he has, as Plugwash said, made it Class I.

I merely said that, at least in terms of what I own and have seen, a high proportion of the items bearing Class II markings has no exposed-c-ps.

What do you mean "a high proportion"? No Class II products should have exposed-c-ps.

Some Class II products have exposed metal but it will/should not be an exposed-c-p by the definition of the term.

 

[JohnW2]

I said it would be silly if avoidable.

You did - but, if one were prepared to do 'whatever was necessary', it always would be 'avoidable', wouldn't it? (or did you perhaps mean something like "avoidable without too much effort"?)

If the OP has connectors in the ceiling cup then he has, as Plugwash said, made it Class I.

Indeed - or, at least, it will have been made "not Class II". If one earthed the exposed metal, then it would be (being used as) Class I.

What do you mean "a high proportion"? No Class II products should have exposed-c-ps. Some Class II products have exposed metal but it will/should not be an exposed-c-p by the definition of the term.

OK, that was perhaps sloppy wording on my part - or, at least, I was using "exposed conductive part" in an everyday sense (i.e. to mean "exposed touchable metal"), rather than the BS7671-defined sense.

As I presume you understand, my point was that if there are no touchable metal parts, then, whatever else one regards it as, the item cannot possibly be Class I.

As regards the definition of Class II, do I take it that you do not regard mechanical damage as being a "fault condition"? I ask because, as you know, the BS7671 definition of an exposed-c-p requires that it "... is not normally live, but which can become live under fault conditions.", and it clearly could become live in the event of certain types/degrees of mechanical damage.

Kind Regards, John

 

[EFLImpudence]

As regards the definition of Class II, do I take it that you do not regard mechanical damage as being a "fault condition"? I ask because, as you know, the BS7671 definition of an exposed-c-p requires that it "... is not normally live, but which can become live under fault conditions.", and it clearly could become live in the event of certain types/degrees of mechanical damage.

Obviously anything is possible - but I think the regulations are that one fault shall not cause any metal to become live.


Presumably, Class I products could have mechanical damage that might sever the CPC before the outside becomes live.

 

[JohnW2]

Obviously anything is possible - but I think the regulations are that one fault shall not cause any metal to become live.

Maybe, but then there would presumably come the question of what constitutes 'one fault'. If a layer of 'reinforced insulation' were the only thing preventing a live part coming in contact with the exposed metal, then a single impact could presumably cause the metal tio become live - but maybe you would call that 'two faults'?

Anyway, that question of mine (about the definition of an exposed-c-p) was only really an afterthought. As I admitted, the initial mistake was mine, in talking about 'exposed conductive part' when i should have said 'exposed metal'.

Kind Regards, John