rewiring a vintage (?) lamp

[Adam Funk]

A relative gave me a flaky table lamp to look at. It turns out that it had a blown lamp & a loose connection in the lampholder. It also had a semi-antique MK plug & zipcord (single-insulated 2-core flex), which I said needed replacement.

whole thing consists of alternating pieces of glass & plastic, topped with a switched BC lampholder, all held together with a steel tube threaded at both ends, with a nut on the bottom (inside the base) & a knurled nut on top with an external thread that the lampholder screws onto.

one of my boxes of crap^W surplus parts I found a double-insulated, two-core flex cable that would fit through the pipe, but I'm concerned about the lack of earthing on the pipe, the possibility that the pipe's edges might damage the cable (at either end). (When the whole thing is assembled, the only exposed metal is the nut & the end of pipe in the base.)

Suggestions? (I doubt this is a valuable antique, so "chuck it because it can't be done right" is a possible answer.)

Thanks, Adam

[Graham.]

replace the plastic lampholder with a brass one, which will have an earth terminal, and use 3 core flex

[Owain]

You need a grommet to fit inside the threaded tube - this one is for

10mm tube you also need a cable clamp because there isn't one at the lampholder for 10mm

If the threaded tube is half-inch you may need a coupler and a

a reducing bush down to 10mm and one of the above

Owain

[Brian Gaff]

Assuming the tube has enough clearance for that ccable. I am sure I've seen similar lamps with some kind of gunge, maybe silicon in the bottom of that tube so the two core cannot get near the edge of the tube, kind of like a diy grommet!

Brian

[meow2222]

If you're going to fit double insulated cable, the metal tube shouldn't nee= d earthing, as long as the detailing's ok at the top it'll be class II. If = the detailng's wrong, ie a stray flex end could touch the tube, the 2 flex = ends can generally be tied together to solve the issue.

You may be able to get a small clamp inside the lampholder at the top, perh= aps a cable tie if the flex is fitted in such a way that it doesn't rotate.

NT

[Adam Funk]

I don't think 3-core flex will fit through the tube or through the notch in the side of the base (not clear in the photos) that lets the base sit flat on a table if you pass the flex out the right way.