Advice on re-wiring old metal lights

[john777]

I am currently trying to re-wire three old metal lamps, two desk lamps and an industrial clamp light. Have tried to engage an electrician to do them but they are not keen as these things can take a lot of time to do. So I am going to give it a go and then get them checked and PAT tested.
During the course of my efforts a number of questions have come up.

1) Given the difficulties in threading 3 core wire through the bodies of old lights, is there such a thing as a lampholder which is either metal effect or is metal sheathed, but is classed as a double insulated lampholder so that a 2 core wire can be used. If yes then does anyone know a stockist for these.
2) If a 3 core wire cannot be successfully threaded through the body of a metal lamp, is it possible to earth the lamp from a different position i.e the base of the metal lamp and then take it out to the plug. I have seen a number of different clip on and screw on eyelets which could be used for this purpose. I am also assuming full continuity through the lamp.
3) If it is possible to earth from the chassis can a normal piece of plain wire be used or from a legal viewpoint does it have to have the green and yellow sheath on.​

Would be grateful for any advice rec'd as these things are starting to drive me mad.
Thanks for reading

 

[Marvo]

Can you attach a picture or two of the lamps you're referring to? It would be helpful to know what they are exactly.

 

[john777]

Hello
This is the chrome desk lamp - the shade is metal
The other one is almost identical but in brass, I did have a industrial clamp light but the holes are wide enough to get a 3 core cable through
With the two desk lights I can just about get the cable through but it restricts the movement of the stem which is meant to be flexible.
Another problem is that the chrome one has an open base which means the wires going to the toggle switch are exposed at the point the connect to the swithch, so I would assume a new base needs to go on
Thanks for reading

 

[crawf]

What size cable are you using??