Lamp wiring parts

[D.M. Procida]

I picked up a rather nice brass lamp in a second-hand shop, but the internal wiring was rather gruesome, so I've pulled it all out to rewire from scratch.

The bulb contacts are riveted into a pair of ceramic holders; here's a picture .

The wire is crimped into the contacts, in a very inaccessible way. I think the only way of rewiring onto those contacts will be to drill out the rivets, then rivet them back in again once I have replaced the wire, unless anyone has any better suggestions.

Are those ceramic holders a standard kind of fitting?

The lamp can be adjusted for height, and a section of the wiring was this curly cable: . It's two-core, and what looks like the third core in the photo is actually elastic, to accommodate the stretch.

Does that kind of cable have a name?

Thanks,

Daniele

[tabbypurr]

2nd link is wrong one. Why don't you just splice to the existing cable for the lampholders

NT

[D.M. Procida]

So it is - here is the curly cable:

That was the existing arrangement, and the splices, subject to years of movement in the brass tube, was looking rather unhealthy.

Daniele

[tabbypurr]

splices should be immobilised if needed. You're not really saying enough about the setup to take this much further.

NT

[Andrew Gabriel]

They aren't rewirable - the wire is part of the lampholder. The wire is specially high temperature, and sometimes steal rather than copper to cope with running continuously at high temperature, and with very high temperature insulation.

Looks like part of an R7s lampholder, but as I can't see the contacts, I can't be sure.

If you are rewiring, I would look to changing it to take a different type of lamp. I rewired several halogen uplighters a few years back, to take LED retrofits for 2D fluorescents.

?

[D.M. Procida]

Thanks, that's exactly what it is.

The arrangement is very similar to some of the ones at

- in particular.

In that case I will just take care of splicing it properly.

That's a good idea. What sort of LED did you use?

Daniele

[Graeme]

In message , D.M. Procida writes

I have a mains cable for a Philips electric razor, which is curly like that, although lacks the elastic. See eBay item 232580903388.

[Vir Campestris]

What kind of lamp runs at nigh on 1000C to make copper care?

Andy

[Andrew Gabriel]

Copper can run up to 150C and form only protective Cu2O oxide layer in air. At 200C and up, different copper oxides are formed which slowly flake off, so they are not protective, but deteriorating.

Halogen lamps have to operate at a minimum bulb-wall temperature of 250C for the halogen cycle to keep the bulb wall clean, and normally run very much hotter than this. The lamp caps typically run at about 350C, depending on ventilation, and they are designed to cope with additional heating from poor lamp contacts. Copper could be used with gas-tight connections and air-tight insulation, but even PTFE is only good to around 260C, and glass fibre insulation which can run hotter is not air tight. So you'll sometimes find copper, but often something else is used instead for longer life.

[Vir Campestris]

Thank you. Interesting!

Andy

[D.M. Procida]

Given that the wire from each terminal of the lampholder is steel rather than copper, does it matter how this is connected to the copper wire further along? Is there a preferred way to do it?

Daniele