NO EARTH FOR LIGHT FITTING

[Christhejag]

I realise this has been covered before, but couldn't find an answer to my problem.

I have a metal light fitting with a 12v transformer inside powering 9 bulbs on arms. The transformer has a Double insulation symbol but the light has an earth wire. Looking at it, it appears that this is only connected to the casing, as just 2 wires into transformer, but the only cable running through this is 12v. Do I need to earth?

 

[ColJack]

yes..
there is the possibility of the live wires into the fitting comming loose and touching the metal fitting.. so it needs earthing.

 

[Christhejag]

Thanks I see your point. So how does a double insulated fitting work?

 

[ColJack]

DI fittings are generally all plastic..

 

[ericmark]

I realise this has been covered before, but couldn't find an answer to my problem.

I have a metal light fitting with a 12v transformer inside powering 9 bulbs on arms. The transformer has a Double insulation symbol but the light has an earth wire. Looking at it, it appears that this is only connected to the casing, as just 2 wires into transformer, but the only cable running through this is 12v. Do I need to earth?

If the transformer is built into the fitting then yes you need an earth.
If the transformer is independent of the fitting and the fitting is only supplied from the output of the transformer no it does not require an earth.

I have seen before where Class II devices are contained within Class I devices and the presence of the

mark has confused people one where this often happens is with mag mount drills where the drill is class II but the base is Class I.

I would say if you have any uncertainty do not use. Although the ESC seem to feel you can still have earth less light fittings I would say that any faults found on a PIR (Periodic Inspection Report) should be corrected before the next report is due. Since this should be done every 10 years on domestic then a home tested in 1965 it would have passed. (Regs changed in 1966) In 1975 it would have failed and it should have been corrected by the inspection in 1985 to in 2009 to have same faults as should have been reported 30 years ago is not the actions of a responsible owner and before spending any money on aesthetics the essential work should be completed so I would expect a house with no earth on lighting to be still using standard ceiling rose and to as much as possible be putting safety first.

 

[dannyboi2003]

DI fittings are generally all plastic..

I thought the same until i bought some new lights for my house. Their a fancy chromy affair with 12v capsule lamps with the transformer in the rose of the fitting. When i got round t putting them up there was no earth wires to be seen and a note in the instructions stating no earth to be connected to the fitting as its DI. The cables into the transformer are DI but what about the connection block for the ains wiring?? Im not convinced myself but if the instructions say its DI what can you do

 

[Christhejag]

Yes thanks Dannyboi I know you can get metal DI fittings they sell them on the website top of page. Sounds like you have exactly the same type of fitting as me, but they decided to add an earth to mine, which is why I asked the question 'how do DI fittings work' as the connector block with live wires is always there. Although they do tell you to wrap 2 layers of tape around them.

 

[Adam_151]

As far as I'm concerned a fitting that has a connector block directly inside a metalic base does not qqualify as DI (even if the MIs say to wrap it in tape ), I'd recommend not installing such an item and taking the issue up with the manufacturer/importer

 

[RF Lighting]

Are you sure it isn't just the transformer which is DI, and the fitting is actually class 1?

 

[Christhejag]

Thanks for all the input guys.

Obviously the fitting requires an earth as overall it is class 1 with a DI transformer.

The lady was advised about the lack of an earth on lighting circuit and the necessity for a rewire, when she moved in. And when she told me she had ordered new light fittings, the first thing I said is 'are they metal' and suggested they would most likely need an earth.

She will have to have a rewire or send them back, I'll leave that to her.

 

[IJWS15]

DI fittings are generally all plastic..

Jut bought a fireplace with two downlighters in it, marked as double insulated, no earth connected, metal mains voltage downlighters.

Just swopped two bathroom downlighters (like for like) for my daughter, also metal with double insulated marking on them and other than a third terminal for the incoming earth no earth connections at all.

 

[bernardgreen]

Double insulated electronic transformer. Apparently designed to have a separation between input (230 Vac ) and output ( 12Vdc ) able to withstand 2000 volts.

When it failed there was enough carbon and vapourised copper deposited on the remains of the PCB to create a conductive path between mains input and the output terminal.

Cutting open an identical unit one has to say that the "designer" obviously had a different set of standards to UK and a lot, an excessive lot, of faith in the insulation used in the components.

If there is mains and a metal ( or otherwise conductive surface ) then I would always earth it even if the ( over confident ) manufacturers say it is not needed.

 

[ban-all-sheds]

Would you care to read the last sentence of 412.2.2.4?

 

[dannyboi2003]

Bernard i have to disagree, if there is an earth fly lead present then it should be connected to earth. If the instructions that come with the fitting explicitly say not to earth the fitting as was the case with mine then i wouldn't, for all we know it may be using part of the metal body to pass either + or - 12v to the lamps. If the instructions are not clear or in another language as they often are then contact the retailer or manufacturer to clarify or use your own good judgement. Just because its metal or has a metal case doesn't mean it "has" to be earthed.

 

[bernardgreen]

Would you care to read the last sentence of 412.2.2.4?

If you would care to quote it here I will be happy to read it.