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 https://www.dropbox.com/s/2mscxp11nl3u4d3/IMG_0238.jpg?dl=0.

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:
https://www.dropbox.com/s/2mscxp11nl3u4d3/IMG_0238.jpg?dl=0. 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

On Saturday, 2 December 2017 17:15:00 UTC, D.M. Procida wrote:
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 https://www.dropbox.com/s/2mscxp11nl3u4d3/IMG_0238.jpg?dl=0.

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:
https://www.dropbox.com/s/2mscxp11nl3u4d3/IMG_0238.jpg?dl=0. 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

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


NT

wrote:

On Saturday, 2 December 2017 17:15:00 UTC, D.M. Procida wrote:

The bulb contacts are riveted into a pair of ceramic holders; here's a
picture https://www.dropbox.com/s/2mscxp11nl3u4d3/IMG_0238.jpg?dl=0.

The lamp can be adjusted for height, and a section of the wiring was
this curly cable:
https://www.dropbox.com/s/oq3gep524s0es6u/IMG_0240.jpg?dl=0. It's
two-core, and what looks like the third core in the photo is actually
elastic, to accommodate the stretch.

2nd link is wrong one.

So it is - here is the curly cable:
https://www.dropbox.com/s/oq3gep524s0es6u/IMG_0240.jpg?dl=0

Why don't you just splice to the existing cable for the lampholders

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

Daniele

On Saturday, 2 December 2017 19:32:19 UTC, D.M. Procida wrote:
tabbypurr wrote:

On Saturday, 2 December 2017 17:15:00 UTC, D.M. Procida wrote:

The bulb contacts are riveted into a pair of ceramic holders; here's a
picture https://www.dropbox.com/s/2mscxp11nl3u4d3/IMG_0238.jpg?dl=0.

The lamp can be adjusted for height, and a section of the wiring was
this curly cable:
https://www.dropbox.com/s/oq3gep524s0es6u/IMG_0240.jpg?dl=0. It's
two-core, and what looks like the third core in the photo is actually
elastic, to accommodate the stretch.

2nd link is wrong one.

So it is - here is the curly cable:
https://www.dropbox.com/s/oq3gep524s0es6u/IMG_0240.jpg?dl=0

Why don't you just splice to the existing cable for the lampholders

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

Daniele

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


NT

In article ,
(D.M. Procida) writes:
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 https://www.dropbox.com/s/2mscxp11nl3u4d3/IMG_0238.jpg?dl=0.

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.

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.

Are those ceramic holders a standard kind of fitting?

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.

The lamp can be adjusted for height, and a section of the wiring was
this curly cable:
https://www.dropbox.com/s/2mscxp11nl3u4d3/IMG_0238.jpg?dl=0. 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

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Andrew Gabriel wrote:

The bulb contacts are riveted into a pair of ceramic holders; here's a
picture https://www.dropbox.com/s/2mscxp11nl3u4d3/IMG_0238.jpg?dl=0.

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.

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.

Are those ceramic holders a standard kind of fitting?

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

Thanks, that's exactly what it is.

The arrangement is very similar to some of the ones at
http://www.cordsncables.co.uk/acatalog/R7s_Lamp_holders_for_double_ended_linear_tungsten_ halogen_lamps.html
-
http://www.cordsncables.co.uk/acatalog/EMC%20A02%20R7S%20PG%20106.jpg
in particular.

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

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.

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

Daniele

In message
,
D.M. Procida writes
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?

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

On 02/12/2017 20:32, Andrew Gabriel wrote:
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.

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

Andy

In article ,
Vir Campestris writes:
On 02/12/2017 20:32, Andrew Gabriel wrote:
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.

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

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.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 04/12/2017 11:17, Andrew Gabriel wrote:
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.

Thank you. Interesting!

Andy

Andrew Gabriel wrote:

In article ,
Vir Campestris writes:
On 02/12/2017 20:32, Andrew Gabriel wrote:
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.

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

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.

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