Retro fit MR16 with LED's

cyberspider

Hi,

I have recently moved into a new house with 78 12 volt down lighters. I want to change these to LED so they are cheaper to run and last longer so a bulb does not need to be changed every day. I have also heard some horror stories about the light fitting causing smouldering in the ceiling as they get too hot. Some lights are on Dimmer Switches and one room is a bathroom:

Room 1 6 lights - Dimmer
Room 2 15 lights - Dimmer
Room 3 17 lights - No Dimmer
Room 4 6 lights - No Dimmer - Bathroom
Room 5 8 lights - Dimmer
Room 6 8 lights - No Dimmer
Room 7 6 lights - No Dimmer
Room 8 4 lights - No Dimmer
Room 7 8 lights - Dimmer


I am looking for recommendations on what best to do. Can I just exchange the bulbs with LED equivalents, should I rip the fittings and transformers out and put in Gu10 fittings or should I look at something else.

Thanks in advance for any suggestions.

I should point out that the existing bulbs are all 50 watt and I will be getting an electrician to do the job.

salmocab

Im sure somebody will confirm this but the 12v transformers don't work with LED lamps so you would need to replace them with LED drivers so it would probably be easier and cheaper to remove the transformers and use GU10 LED lamps instead. The dimmer switches would probably need to be replaced too. It would certainly be worth your while but could be fairly expensive initially to buy.

cyberspider

Thanks Salmocab,

I suspected that this might have been the case. I know that it will be a high outlay to begin with but considering the number of lights I felt it could pay for itself pretty quickly in money and hassle of changing bulbs.

2011

cyberspider wrote: »

I am looking for recommendations on what best to do. Can I just exchange the bulbs with LED equivalents, should I rip the fittings and transformers out and put in Gu10 fittings or should I look at something else.

Hi Cyberspider,

If I were doing this I would replace the existing with GU10 LED lamps.

Have a read of this and come back if you have any questions:
http://www.boards.ie/vbulletin/showthread.php?t=2056469034

Post #1 proivdes a good overview.

Hoagy

Just wondering, if you change from 12v to 230v lamps, couldn't there be an issue with earthing?

2011

Hoagy wrote: »

Just wondering, if you change from 12v to 230v lamps, couldn't there be an issue with earthing?

Assuming the house is wired correctly each existing transformer should be wired such that there is an earth on the primary side (most likely unterminated).

From memory my GU10 down lighters do not have an earth connection.

If the existing lights are wired incorrectly and do not have an earth I don't see how this change would exacerbate the problem.

mikeyjames9

2011 wrote: »

If the existing lights are wired incorrectly and do not have an earth I don't see how this change would exacerbate the problem.

the existing lights are ELV so won't have an earth terminal

it's difficult to see how this conversion can be done properly from 12v to mains


although it it is being done with flyleads and connectors presumably judging by previous postings here on the matter

2011

mikeyjames9 wrote: »

the existing lights are ELV so won't have an earth terminal

With all due respect, how could you possibly know that?

it's difficult to see how this conversion can be done properly from 12v to mains

Easy peasy.
It is done every day of the week.

If concerned there are 2 options available:
1) Plastic lights (yes they can look good, very discrete)
2) Replace with fittings that have an earth terminal and earth same.

mikeyjames9

2011 wrote: »

With all due respect, how could you possibly know that?

because 12v downlights are SELV with no earth connection

2011

mikeyjames9 wrote: »

because 12v downlights are SELV with no earth connection

That does not mean that they have no earth terminal.

There are down lighters available that are designed for both 12V and mains voltage that have an earth terminal.

Failing that there are the options available that I suggest in my previous post.
This is not a difficult issue to resolve.

mikeyjames9

2011 wrote: »

That does not mean that they have no earth terminal.

There are down lighters available that are designed for both 12V and mains voltage that have an earth terminal.

.

unlikely scenario here

2011

mikeyjames9 wrote: »

unlikely scenario here

Not in my experience

But as I said easy to resolve.
I still don't see why you think this is "difficult" even if there is no earth terminal.
Please explain.

mikeyjames9

2011 wrote: »

Not in my experience

But as I said easy to resolve.
I still don't see why you think this is "difficult" even if there is no earth terminal.
Please explain.

fair enough maybe you have seen plenty of these "dual-voltage spotlight fittings" in domestic use

i recall seeing them for groundlights-cant recall seeing any ceiling lights

i was referring to diy flylead replacement, not light fitting replacement which is perfectly acceptable

2011

I am open to correction here but from memory there are plenty of metal GU10 down lighters that do not have an earth terminal as they do not require it (due to the design).
Perhaps someone can confirm.

mikeyjames9

2011 wrote: »

I am open to correction here but from memory there are plenty of metal GU10 down lighters that do not have an earth terminal as they do not require it (due to the design).
Perhaps someone can confirm.

doubt it considering it's regulations to have a cpc at a "point"

it would neccessitate use of a JB


i remember plenty in the early days of GU10 spots but then they all seemed to have an earth terminal later

2011

mikeyjames9 wrote: »

doubt it considering it's regulations to have a cpc at a "point"

You have misread my post.
I am not suggesting that there should not be a CPC wired to the point, there should.
There are many electrical devices that do not require an earth due to their design despite the fact that they have exposed metal parts yet the regulations state that a CPC must be wire to the point such as this.
These items are frequently Double Insulated.

unlikely scenario here

Here is a popular make of downlighter that is designed for both MR16 (12V) and GU10 by Ansell with an earth terminal.

mikeyjames9

2011 wrote: »

You have misread my post.
I am not suggesting that there should not be a CPC wired to the point, there should.
There are many electrical devices that do not require an earth due to their design despite the fact that they have exposed metal parts yet the regulations state that a CPC must be wire to the point such as this.
These items are frequently Double Insulated.




Here is a popular make of downlighter that is designed for both MR16 (12V) and GU10 by Ansell with an earth terminal.

thankyou i know all about double insulation


why do you think manufacturers would supply mains luminaires without an earth terminal to at least terminate the circuit cpc?

even if it's not required to be connected to the frame of the fitting

mikeyjames9

i was responding to your earlier post regarding metal gu10 downlighters


i have not seen any of these in double insulated type recently

maybe they are available i don't know

2011

mikeyjames9 wrote: »

thankyou i know all about double insulation

I thought you might
Not everyone reading may understand the concept though.
Apologies if I came across as condescending, that was not my intention.

why do you think manufacturers would supply mains luminaires without an earth terminal to at least terminate the circuit cpc?

even if it's not required to be connected to the frame of the fitting

Frequently electrical equipment that does not require an earth will not have a terminal top connect an earth to.
This looks like an example.
Woodies finest :rolleyes:

Some manufactures produce awful rubbish and have no regard for the installer.
Garo springs to mind.
I have very bad memories of Garo products, perhaps they have improved since.
From my experience: Their distribution boards never have enough earth terminals, their terminals are always too small, their screws deform as though they are made of chocolate which probably explains why the threads frequently striped off.
At the other end of the spectrum there are makes like ABB and MK.

In Ireland earthing is something that we take quite seriously.
In places like Italy they don't really "do" earthing, in general they just don't "get it". France and Spain are almost as bad.

I remember an architect free issuing some of the most beautifully sculpted lights I have ever seen. By their appearance it was obvious that they required an earth but there was no earth terminal available. Just like a Ferrari, incredibly stylish, Italian, difficult to work on and completley impractical

Sir Arthur Daley

There are GU10s available which do have an earth terminal and one that don't, different manufactures have their own spec. Open back and can type. Any MR16 downlighter i ever bought never had an earth terminal, not saying they are not out there never fitted one.
The down lighters i have seen that come with a GU10 and MR16 lead that can be wired both ways specified by manufacturer are open back ones with no earth terminal. The only can type lately i have seen is ic ones and in the installation manual it says:

if you are using the MR16 lead to disconnect the earth connection to the downlighter, when using the MR16 lead is classified as class 3 and should not be earthed.

The op needs to follow manufacturer instructions for conversion if said lights are permitted to be converted by manufacturer. Another thing to consider op is possibility of changing dimmers to suit the new loading of the leds.

mikeyjames9

yes


it is not allowable to connect an earth to the metal chassis when using SELV


if you do it is no longer SELV afaik

2011

mikeyjames9 wrote: »

yes


it is not allowable to connect an earth to the metal chassis when using SELV


if you do it is no longer SELV afaik

That is not correct

The output (secondary side) of a transformer supplying an SELV circuit is completely isolated from earth. Therefore an earth connection is pointless form the perspective of the SELV circuit. Connecting the metal enclosure of a device that contains an SELV circuit will not alter the fact that it is an SELV circuit.

IEC defines a SELV system as "an electrical system in which the voltage cannot exceed ELV under normal conditions, and under single-fault conditions, including earth faults in other circuits".

The part about "including earth faults in other circuits" is referring to the fact that the an SELV circuit does not have any part of the circuit connected to earth. If any part of it was an external earth fault could cause part of the circuit to rise to a potential above ELV.

2011

Sir Arthur Daley wrote: »

Any MR16 downlighter i ever bought never had an earth terminal, not saying they are not out there never fitted one.

The Ansell downlighter that is designed for both MR16 (12V) and GU10 has an earth terminal.

Another thing to consider op is possibility of changing dimmers to suit the new loading of the leds.

Leading edge dimmer switches will do the job.

Sir Arthur Daley

2011 wrote: »

The Ansell downlighter that is designed for both MR16 (12V) and GU10 has an earth terminal.

I was being specific to an MR16 fitting. Your example is a combi, have a look where the earth terminal is, its on the GU10 lead metal part. Its a bomb proof design.

mikeyjames9

2011 wrote: »

That is not correct

The output (secondary side) of a transformer supplying an SELV circuit is completely isolated from earth. Therefore an earth connection is pointless form the perspective of the SELV circuit. Connecting the metal enclosure of a device that contains an SELV circuit will not alter the fact that it is an SELV circuit.

IEC defines a SELV system as "an electrical system in which the voltage cannot exceed ELV under normal conditions, and under single-fault conditions, including earth faults in other circuits".

The part about "including earth faults in other circuits" is referring to the fact that the an SELV circuit does not have any part of the circuit connected to earth. If any part of it was an external earth fault could cause part of the circuit to rise to a potential above ELV.

i see what you mean


the system still complies with SELV as the secondary isn't earthed and the supply voltage won't rise if the fitting is earthed

my point should have been that the fitting supplied via selv should not be earthed


Class III - symbol
The luminaires in this class are those in which protection against electric
shock relies on supply at Safety Extra-Low Voltage (SELV), and in which
voltages higher than those of SELV (50 V a.c. r.m.s.) are not generated.
An a.c. operating voltage of 42 V maximum is common. A Class III
luminaire should not be provided with a means for protective earthing.
http://www.lighting.philips.com/pwc_li/in_en/assets/docs/products/Information.pdf

2011

Sir Arthur Daley wrote: »

I was being specific to an MR16 fitting. Your example is a combi

Correct, if it was MR16 only the earth would be pointless as per the discussion with mikeyjames9

have a look where the earth terminal is, its on the GU10 lead metal part. Its a bomb proof design.

A beauty

Sir Arthur Daley

2011 wrote: »

Correct, if it was MR16 only the earth would be pointless as per the discussion with mikeyjames9

Completely agree never said otherwise. Changing to GU10 is something the op needs to take into consideration in terms of earthing or not. This decision is down to the manufacturer.