Antique light, convert to 12V?

[Pretty Mouth]

A customer bought a metal antique lamp in Rome, and is very keen to get it installed. There's no means of earthing it, and is wired with thin, single insulated conductors, so I have ruled out using it at 230V. However I am considering converting it to 12V, by installing a 12V LED driver upstream, and then using a 12V E27 lamp, such as those used for caravans.

Has anyone done anything similar to this, or can anyone think of any problems with this conversion?

 

[mainline]

A customer bought a metal antique lamp in Rome, and is very keen to get it installed. There's no means of earthing it, and is wired with thin, single insulated conductors, so I have ruled out using it at 230V. However I am considering converting it to 12V, by installing a 12V LED driver upstream, and then using a 12V E27 lamp, such as those used for caravans.

Has anyone done anything similar to this, or can anyone think of any problems with this conversion?

View attachment 102015
View attachment 102016

Doesn't the bayonet unscrew, if so you could replace with one that has the earth tag on it

 

[LukeD]

I tend to work with interior designers a lot and this issue is a major problem. Antique lamps with modern bulbs looks "krap" . So firstly many collectors have spent the last few years buying bulbs up from all over the place .The National Trust and other big estates have spent fortunes buying all they can. I sometimes get lovely jobs wiring up expensive Chandeliers And Have found cable for model railways etc has worked fine !! Nothing else runs through the arms easily . As for earthing .Its always possible . The neck on your lamp is not so narrow . so finding a 3 way to get through should be Ok?

 

[davesparks]

I'd replace that cable whatever source of supply it's being connected to, gold or brown flex would look a lot better too.

See if you can replace the lampholder with one that has an earth terminal, they shoukd just screw in.

 

[7029 dave]

I would try and covert the lamp holder to brass BC with earth term and rewire with gold or brown 3core flex.
Thats what I did to my mothers old standard lamp.

 

[Carolina]

I'd replace that holder wiring first, you don't know if the insulation is in good shape inside until you pull it out.

I've rewired whole chandeliers for 12V so it's certainly doable. What I did was keep AC wiring at the switch and do the conversion to DC at the fixture itself to avoid two issues: voltage drop and switch arcing, this last one because I was working with high currents.
My PSUs are bulky because I'm using incandescent bulbs but if you're using LED you could get away with a tiny 1A driver depending on the wattage of the bulb you want to use.

 

[brianmoooore]

I would try and covert the lamp holder to brass BC with earth term and rewire with gold or brown 3core flex.

Brass 'rose' at the top will need an earth tag as well.

Antique lamps with modern bulbs looks "krap"

"Antique" LED lamps have never been more readily available. Dozens of designs to choose from.

 

[Pretty Mouth]

Thanks for your replies so far. Something to add, which isn't clear in the pictures:

The 'base' or 'cup' that fits against the ceiling has a narrow tube at the bottom, through which the wires pass on their way down to the lampholder. The chain hangs from this tube, the first link passing through it at right angles to the tube's direction, creating an obstruction. One of the wires passes one side of the obstruction, the other passes the other side, without room to spare. It won't be possible to get sheathed flex through this tube, there just isn't room.

Also, I think it will be difficult to earth the 'cup', it's quite thin metal. I don't think my customer will go for a brass screw bolted through it. I considered soldering a core of flex to the inside of it, but I'm not sure how well it would take to it.

Bulb choices are limited at 12V, but I found these on amazon that don't look too awful:

https://www.amazon.co.uk/Bonlux-Filament-Vintage-Equivalent-Halogen/dp/B07VHYGHKD/ref=dp_prsubs_2?pd_rd_i=B07VHYGHKD&th=1

 

[brianmoooore]

Low Voltage 24V ST64 6W Edison LED Filament Bulb Lamp 12V 36V E27 Vintage Antique Retro Edison E27 Led Bulbs Replace 60W Incandescent Light AC/DC12-36V 2-Pack : Amazon.co.uk: Lighting

Low Voltage 24V ST64 6W Edison LED Filament Bulb Lamp 12V 36V E27 Vintage Antique Retro Edison E27 Led Bulbs Replace 60W Incandescent Light AC/DC12-36V 2-Pack : Amazon.co.uk: Lighting

www.amazon.co.uk

More antique look.

 

[LukeD]

Brass 'rose' at the top will need an earth tag as well.

"Antique" LED lamps have never been more readily available. Dozens of designs to choose from.

Never found them to really look the "same" . Thats why so many people bought as many as possible .I know of one person that spent thousands and he could if he really wanted to sell them all on and make big coin. Trouble is he wants them ! As They are getting super rare

 

[Lucien Nunes]

I considered soldering a core of flex to the inside of it, but I'm not sure how well it would take to it.

If correctly prepared and soldered it will take perfectly. The problem is that you will need sufficient heat that the outside might be discoloured at the location of the soldering, unless the whole thing is polished bright afterwards, which might not be desirable.

The inability to get a sheathed flex through sounds like a bit of a showstopper though.

 

[brianmoooore]

You could drill a 10mm hole in the 'cup', near where the chain attaches, fit a small rubber grommet in the hole, and bypass the blockage.
Use a small brass threaded bush instead of the grommet, and you could use this to attach a ring terminal inside for the earthing.

 

[mainline]

Thanks for your replies so far. Something to add, which isn't clear in the pictures:

The 'base' or 'cup' that fits against the ceiling has a narrow tube at the bottom, through which the wires pass on their way down to the lampholder. The chain hangs from this tube, the first link passing through it at right angles to the tube's direction, creating an obstruction. One of the wires passes one side of the obstruction, the other passes the other side, without room to spare. It won't be possible to get sheathed flex through this tube, there just isn't room.

Also, I think it will be difficult to earth the 'cup', it's quite thin metal. I don't think my customer will go for a brass screw bolted through it. I considered soldering a core of flex to the inside of it, but I'm not sure how well it would take to it.

Bulb choices are limited at 12V, but I found these on amazon that don't look too awful:

https://www.amazon.co.uk/Bonlux-Filament-Vintage-Equivalent-Halogen/dp/B07VHYGHKD/ref=dp_prsubs_2?pd_rd_i=B07VHYGHKD&th=1

You could take the original fitting out and use a brass tube with a modern hook type fitting, there are various domed heads that wouldn't look out of place

Brass M10 Threaded tube | eBay

Brass M10 1mm fine Pitch Threaded rod hollow tube in various pre cut lengths of 50mm or 75mm. All sold in singles.

www.ebay.co.uk

 

[Pretty Mouth]

I don't really want to make any modifications to the fitting if I can help it, so I think it has to be 12V. 60W E27 incandescent lamps are still available in 12V, which I think the customer would like, as they can be dimmed. However, that's 5A through those skinny conductors, which I don't think they'll be able to handle.

 

[cireland]

Is it possible to rewire with gold flex then split them at the chain link?
Or would that show basic insulation?

 

[Carolina]

I don't really want to make any modifications to the fitting if I can help it, so I think it has to be 12V. 60W E27 incandescent lamps are still available in 12V, which I think the customer would like, as they can be dimmed. However, that's 5A through those skinny conductors, which I don't think they'll be able to handle.

For a single bulb 0.75 mm2 wiring is fine.
But it'll require a large power supply (or even larger transformer), and on top of that a soft starter circuit because otherwise the inrush current will constantly trip OCP in the PSU making the bulb flicker trying to reach operating temperature.
Adding a dimmer to all of that is, no offense, begging on your knees for problems.

 

[davesparks]

For a single bulb 0.75 mm2 wiring is fine.
But it'll require a large power supply (or even larger transformer), and on top of that a soft starter circuit because otherwise the inrush current will constantly trip OCP in the PSU making the bulb flicker trying to reach operating temperature.
Adding a dimmer to all of that is, no offense, begging on your knees for problems.

Up until a couple of years ago when LED took over we were fitting 12V 50W lamps with their own PSU by the bucket load, often fed by a dimmer too. I don't think a couple of years and an extra 10W is going to suddenly make this the difficult task you are suggesting!

And why is adding a dimmer begging for problems?

 

[mainline]

For a single bulb 0.75 mm2 wiring is fine.
But it'll require a large power supply (or even larger transformer), and on top of that a soft starter circuit because otherwise the inrush current will constantly trip OCP in the PSU making the bulb flicker trying to reach operating temperature.
Adding a dimmer to all of that is, no offense, begging on your knees for problems.

I don't understand why a PSU that is made to run a particular item would trip its OCP ? (if indeed it has one that resets that fast to make the item flicker) If that is the case, then it's obviously not a suitable PSU

 

[mainline]

Up until a couple of years ago when LED took over we were fitting 12V 50W lamps with their own PSU by the bucket load, often fed by a dimmer too. I don't think a couple of years and an extra 10W is going to suddenly make this the difficult task you are suggesting!

And why is adding a dimmer begging for problems?

I would have thought that most modern dimmers would have a soft start anyway.

 

[Carolina]

Up until a couple of years ago when LED took over we were fitting 12V 50W lamps with their own PSU by the bucket load, often fed by a dimmer too. I don't think a couple of years and an extra 10W is going to suddenly make this the difficult task you are suggesting!

And why is adding a dimmer begging for problems?

You're right I always forget small power supplies for lighting are a thing, I was probably thinking about all of the problems I had when trying to make my 12V lights work using cheap LED drivers.

I bought a couple of 5A one because I thought 5A=60W and forgot that a cold filament draws more current so even if the brick had enough power it'd constantly trip making the bulb flicker forever. Ended up using them for 40W bulbs instead of designing a soft-starter and called it a day.