Where does the Earth go?

[simondyntDBeK]

Hi all,

I've bought two of these for the loft:

https://www.lightrabbit.co.uk/new-18-watt-frosted-led-surface-mounted-ceiling-light.html

I have a simple light switch and ceiling rose up there already so was just going replace the cable from the switch to a terminal strip in the first light then run a second cable on to the second light but I'm not sure what to do with the Earth in the cable? The existing ceiling rose has a dedicated screw to put the earth into but there's nothing obvious in the new lights.

Thanks!

 

[EFLImpudence]

Looks like plastic, and the power supply is double insulated (square in square symbol) so doesn't need an earth.

The earth wire in the supply cable - just put it in a terminal block so that it can't touch anything.

 

[simondyntDBeK]

Just read up on double insulation. Great. Thanks!

 

[ban-all-sheds]

Plastic or not, shouldn't the whole item be marked as double insulated, not just one of its internal components?

 

[mattylad]

Probably not, because the light itself is not 240v, its far lower. It's only the power supply that has the mains on that needed to be double insulated.

Although from that pic I'm not entirely sure that the light is actually plastic, looks like its cast and painted white?

 

[JohnW2]

Probably not, because the light itself is not 240v, its far lower. It's only the power supply that has the mains on that needed to be double insulated.

I'm inclined to agree. I have countless items (mobile phones, laptops, tablets, lamps, printers, routers etc. etc. which are supplied/charged via an external 'plug in' ELV power supply/charger (5V, 12V or whatever, without any earth connected to the device, if if one is connected to the PSU/charger) and I don't think any are, or need to be, marked as double insulated.

In fact, if I understand correctly what is going on, I think the label on this particular light (the light itself) might just be plain wrong (and 'dangerous') - since I suspect that if one applied 230V AC to it, it would probably die, with or without bangs and smoke.

Kind Regards, John

 

[Seb101]

Although from that pic I'm not entirely sure that the light is actually plastic, looks like its cast and painted white?

I suspect the same looking at the paint pattern in the edges. In which case you'd expect it to have an earthing terminal, as the most risky failure mode here is the live conductor from the incoming supply to the transformer coming loose and touching the metal casing.

I'm inclined to agree. I have countless items (mobile phones, laptops, tablets, lamps, printers, routers etc. etc. which are supplied/charged via an external 'plug in' ELV power supply/charger (5V, 12V or whatever, without any earth connected to the device, if if one is connected to the PSU/charger) and I don't think any are, or need to be, marked as double insulated.

Regardless of the lamps operation voltage, in this case there is still a live 240V conductor connection inside an non-insulated metal enclosure.

 

[ban-all-sheds]

I'm inclined to agree. I have countless items (mobile phones, laptops, tablets, lamps, printers, routers etc. etc. which are supplied/charged via an external 'plug in' ELV power supply/charger (5V, 12V or whatever, without any earth connected to the device, if if one is connected to the PSU/charger) and I don't think any are, or need to be, marked as double insulated.

I would think that was a different scenario from a piece of equipment with a power supply as an integral component.

In fact, if I understand correctly what is going on, I think the label on this particular light (the light itself) might just be plain wrong (and 'dangerous') - since I suspect that if one applied 230V AC to it, it would probably die, with or without bangs and smoke.

I can't imagine someone being both dim enough to try that and physically capable of connecting 230V AC to that co-ax plug. And why have that connector in the first place? They've got the cost of that in there, but they CBA to provide connectors to allow the thing to be connected to the customer's fixed wiring?

The presence of that label makes me think that the maker regards this product as a single integrated item - I wonder why it doesn't bear a DI symbol? And on the subject of symbols, maybe it's the camera angle, but the CE mark on the power supply doesn't look genuine.

 

[Seb101]

Normally with a non-earthed metal down-lighter the 240V connection is done away from the fixture. Here with the transformer fixed inside the metal housing and such a short tail, you have no option but to do it inside the fixture, which carries additional risks. I would use some fully enclosed clamp style connectors (Wago 222) to be extra sure there is no exposed conductor surface on the incoming connection.

 

[ban-all-sheds]

You'd be relying on the solder on the ends of the flex not creeping. I'd suggest cutting those tinned ends away and using 224s

 

[ban-all-sheds]

I have a simple light switch and ceiling rose up there already so was just going replace the cable from the switch

How is the rose wired?

What cables go to the switch? If there's only one, from the rose, then taking that and connecting it directly to the light won't work.

https://www.diynot.com/wiki/Electrics:Lighting-Rose

 

[JohnW2]

Normally with a non-earthed metal down-lighter the 240V connection is done away from the fixture. Here with the transformer fixed inside the metal housing ....

I wonder whether it is actually fixed inside the housing? The photo in the link provided by the OP shows the back of the light without the driver attached, and shows the driver in a separate photo, on its own.

Mind you, as you say, the length of the driver's output lead is such that one would be hard pressed to locate the driver anywhere other than within the light casing.

Kind Regards, John

 

[EFLImpudence]

Here's another picture.
It is apparently made of aluminium.

The length looks reasonable for placing in the ceiling.

 

[ban-all-sheds]

But there's no cut-out in the body for a cable....

 

[ban-all-sheds]

However - looking more closely at an enlarged photo one can see that the power supply is just lying there.

"C&N" is starting to come to mind....