GU5.3 12v or 240v - how to identfy

[JohnW2]

Not to mention you will be putting 240 volt inside an unearthed metal fitting designed for only 12 volt

You could be right. Your comment makes me realise that, I must confess, I have been assuming that when the OP talks about 'replacing the holders' with GU10 ones, he is actually talking about replacing the fittings with GU10 ones designed for 230V.

As you say, one cannot just change literally just the 'lamp holder' in a 12V fitting and then (safely) apply 230V to it.

Kind Regards, John

 

[EFLImpudence]

Are they any different?

The ceramic lamp holders are the same.

Don't earthed ones just connect the CPC to the bracket which holds the connectors (three instead of two) with only a connection to the can via a spring and the tabs of the can on to which it fits?

 

[JohnW2]

Don't earthed ones just connect the CPC to the bracket which holds the connectors (three instead of two) with only a connection to the can via a spring and the tabs of the can on to which it fits?

I don't know - it's been quite a long time since I handled/examined one. You're probably right, but I would have regarded that as a pretty iffy way of earthing the exposed-c-p of a Class I fitting.

Kind Regards, John

 

[ericmark]

It has been an interesting read. Personally I only have 4 x GU5.3 12 volt MR16 lamps, all the rest are GU10. They (the 4 GU5.3's) are powered by a single toroidal transformer. In real terms they were a fad and not required, but filling in the holes in ceiling would be a pain. So PoundWorld did some 0.58W LED lamps, output really too low, but better than blown bulbs, so 4 fitted, within two months they started to fail so replaced with the same, they also failed so left for a time, I thought likely it needed DC and the peak voltage was causing the lamps to fail.

Then I saw some lamps in Lidi clearly marked 50 Hz so must be designed for an AC supply. Fitted 4 think they were 3W each and non have failed so far. As to if 12 volt GU5.3 lamps are designed for DC or AC I have also found some clearly marked DC at 10 ~ 36 volt. I have not found any marked AC just marked 50 Hz.

As to what supplying a 50 Hz rated lamp with AC in the GHz range would do I don't know? Maybe they would transmit? But I have noted some electronic transformers are now rated 0 ~ 105 VA rather than 35 ~ 105 VA so should be able to supply an LED lamp without shutting down, but would they form a transmitter?

I have looked at this advert there seems to be nothing to show the Hz output

it does not say anywhere it is a switched mode or a pulse width modulated supply but I am sure it is. RFI in compliance with EN55014 but that is the unit stand alone, once you connect external diodes or other devices to it who knows.

So will they interfere with each other? Will they jam radio transmissions? And since they don't tell you the output frequency if they did who would be to blame?

Using a DC power supply may remove the transmission problem, but then can you use LED lamps marked 50 Hz? Likely the answer is yes, but it seems there are so many problems with 12 volt LED lamps I can see why people are moving to 230 volt GU10 instead.

 

[333rocky333]

Are they any different?

There was a time, with open back fittings, when wholesalers did give you the same fitting, with Your choice of holder, 12v or 240v, some were even sold with both holders included.
I must admit I never agreed with the practise, as there was never mention of earthing the fitting.

Later came along enclosed fittings, therefore the lampholders passed through a small hole in the unearthed metal, not really a problem at 12 volt, but as evident by posts here, some people want to replace this 12v holder and therefore create 240 volt through this unearthed hole.
Not so much nowadays, but we have seen this wire burn up with heat, thus creating a possibility of livening up the unearthed, metal casing.
Afaik, the new regulations for Gu10 lampholders now include Double sheathed wires and cable restraint to reduce this problem.
In the few instances where I have reluctantly done this, i have drilled and bolted an earth link to the Main body of the fitting out of sight.

I was always concerned, seing managers relamping Gu10s live as often the wires were in poor state and the connection sometimes even blown or snapped off, with the live wire flapping around inside.

Back in the days, im sure metal eyeballs etc never had earth terminals, though they were fitted with Porcelain ES holders, further protected by a plastic housing and fixed in rather than swinging round inside.

 

[333rocky333]

Don't earthed ones just connect the CPC to the bracket which holds the connectors (three instead of two) with only a connection to the can via a spring and the tabs of the can on to which it fits?

I think they do, but as said they usually come with the New type holders, so in my view, although not labelled such, the holders are close to being Double Insulated standard.
Theres still a lot of old style Gu10 holders that I would not feel happy using, without a better form of earthing, Them spring fit brackets often come unattached and are found laying loose in the void

 

[JohnW2]

As to what supplying a 50 Hz rated lamp with AC in the GHz range would do I don't know? .... I have looked at this advert there seems to be nothing to show the Hz output

You may be interested in this ... (click here) .

As you will see, they examined a number of 12V AC 'transformers' used for supplying LEDs and found that whilst there was considerable variation in the frequency of the 'high frequency' component of the output waveform (in range 10 kHz - 231 kHz), in all the cases they examined that HF component was contained within a 100 Hz 'envelope' - so the load may 'see' it as essentially 100 Hz.

Kind Regards, John

 

[EFLImpudence]

I think they do, but as said they usually come with the New type holders, so in my view, although not labelled such, the holders are close to being Double Insulated standard.

Not arguing - but they can't have it both ways.

Either it's NOT DI and should be earthed - thus relying on the spring to connect all parts

or

It is DI and should NOT be earthed - not even the bracket with the doubtful connection via the spring.

 

[JohnW2]

... or ... It is DI and should NOT be earthed - not even the bracket with the doubtful connection via the spring.

I realise that there is always the argument that unnecessarily earthing anything (whether it is related to an electrical item, a pipe, bath, door knob or whatever) is undesirable because it theoretically increases risks, there is, as far as I am aware, nothing which actually says that one "must NOT" earth a metal structure within which there happens to be a DI electrical item (such as the lampholder we are talking about.

It is far from unknown to have Class II 'modules' of one sort or another within a Class I item of equipment, whose exposed-c-ps are necessarily earthed, but I presume you are not suggesting that such is 'not allowed'?

Kind Regards, John

 

[EFLImpudence]

It depends what you mean by "not allowed".

The manufacturers of a Class 2 product (often? usually? always?) states "This product must not be earthed" (my underline to emphasize they say "must not").
I don't know if you may find one that doesn't. If so, is it an error?
Perhaps there is a standard which states that they should.

Apart from that, earthing a part which does not require it when instructed that it must not be is surely not good workmanship nor wise - as with your bath and door knob (even though, I presume door knob manufacturers do not state it).
The situation is much clearer if you choose the example of the proverbial spoon, as people would consider it stupid to earth spoons but it is no different than the door knob or excesses of the 15th edition - who wrote that?.

There must be a regulation against making the situation worse and increasing risk unnecessarily.
I don't think it is a theory; surely a fact.

Were every product we use Class 2, I am sure some would still earth them because they just think it safer.

 

[333rocky333]

Either it's NOT DI and should be earthed - thus relying on the spring to connect all parts

Would have thought, as you said earlier, they should have a better way, than relying on the spring

 

[JohnW2]

It depends what you mean by "not allowed". The manufacturers of a Class 2 product (often? usually? always?) states "This product must not be earthed" (my underline to emphasize they say "must not").

They often do say that and, in any event, a high proportion of Class II items do not have anything (i.e. exposed-c-ps) which one could earth, even if one wanted to!

However, unless they are just making a general statement that one should not ('must not') unnecessarily earth anything (whether electrical equipment or otherwise) such an instruction does not really make any electrical sense - since it is no more undesirable to earth a metal 'enclosure' containing a Class II item than it is to ('unnecessarily') earth a pipe, bath, spoon or whatever.

I don't know if you may find one that doesn't. If so, is it an error? Perhaps there is a standard which states that they should.

I very much doubt it, and I imagine that there are a lot of Class II items which don't come with such an instruction. As I've said, many of them have no exposed-c-ps, so what on earth would "must not be earthed" actually mean? - i.e. what might one contemplate earthing?

There must be a regulation against making the situation worse and increasing risk unnecessarily. I don't think it is a theory; surely a fact.

Yes, it's a fact, but it's not really anything to do with electrical items, per se, and therefore probably does not come within the scope of electrical regulations. A class II item does not itself become any less safe if exposed metal (outside of the DI) is earthed. It's only the environment (not the Class Ii item) which becomes 'less safe', and I don't know what sort of regulation could outlaw the earthing of metal fixtures and fittings (and spoons!) in general.

Were every product we use Class 2, I am sure some would still earth them because they just think it safer.

As above, I'm not sure what that would mean in relation to the majority of Class II items. As I've asked, exactly what would these people be earthing?

... and don't forget that there is a regulation which requires that a CPC be run to 'every point' in an electrical installation, even if that 'point' is a Class II piece of equipment - so there has to be an earth 'at' a (hard-wired) Class II item, even if it's not (even "must not be"!) connected to anything.

Kind Regards, John

 

[JohnW2]

Would have thought, as you said earlier, they should have a better way, than relying on the spring

Indeed - as I said /implied earlier, I doubt that a connection via an iffy spring would be regarded as an acceptable way to earth the exposed-c-ps of a Class I item in any other situation, so why would it be acceptable in this case?

Kind Regards, John

 

[EFLImpudence]

They often do say that and, in any event, a high proportion of Class II items do not have anything (i.e. exposed-c-ps) which one could earth, even if one wanted to!

No need to say it, then.

However, unless they are just making a general statement that one should not ('must not') unnecessarily earth anything (whether electrical equipment or otherwise) such an instruction does not really make any electrical sense - since it is no more undesirable to earth a metal 'enclosure' containing a Class II item than it is to ('unnecessarily') earth a pipe, bath, spoon or whatever.

I don't think "must not" is just a general statement.
That it is no less undesirable does not alter the fact that it is undesirable.

I very much doubt it, and I imagine that there are a lot of Class II items which don't come with such an instruction. As I've said, many of them have no exposed-c-ps, so what on earth would "must not be earthed" actually mean? - i.e. what might one contemplate earthing?

That is a pointless question.

Yes, it's a fact, but it's not really anything to do with electrical items, per se, and therefore probably does not come within the scope of electrical regulations. A class II item does not itself become any less safe if exposed metal (outside of the DI) is earthed.

Yes it does. It may become not unavoidably live with a fault elsewhere.

It's only the environment (not the Class Ii item) which becomes 'less safe',

No it isn't.

and I don't know what sort of regulation could outlaw the earthing of metal fixtures and fittings (and spoons!) in general.
As above, I'm not sure what that would mean in relation to the majority of Class II items. As I've asked, exactly what would these people be earthing?

It's no good arguing against something by saying other items are plastic.

... and don't forget that there is a regulation which requires that a CPC be run to 'every point' in an electrical installation, even if that 'point' is a Class II piece of equipment - so there has to be an earth 'at' a (hard-wired) Class II item, even if it's not (even "must not be"!) connected to anything.

That is, I believe , just a provision for changing to Class 1 at a later date - for some reason.

I'm not going to argue all night because you do not wish to accept a perfectly valid and reasonable practice and principle -
and keep asking how one can earth plastic spoons.


Earthing is not a good thing in its own right; it is a necessary evil to protect against an unavoidable possible occurrence in some items.
Where this occurrence is protected against by another method then undesirable earthing can be avoided.

 

[JohnW2]

I'm not going to argue all night ...

Fair enough. I've made my points and I, too, have better things to do with my time.

Kind Regards, John