bathroom pull cord

[vik2001]

hi
in my bathroom i have installed a new pull cord light, which works fine. every 2 months or so the red wire inside the pull cord gets disconnected from the screw, and i have to screw it back inside. why is this happening?

i have tightened the wire inside the screw, so whats the reason?

 

[TicklyT]

The copper in cables is quite soft, and deforms as the screw bites into it. If it isn't tight enough, the deformation renders the connection loose after a while.

Loose connections generate heat. As well as damaging the insulation and switch terminals, the heat softens the copper further, which deforms more, so the connection gets looser, until it fails.

You need to tighten down the screws firmly onto bright, clean copper to make a good connection. Trim back the ends of overheated and oxidised wires.

Overtighten a terminal, and the screw may cut right through the copper, or you may strip the thread or wring the head off the terminal screw. It's a matter of developing a feel for a correctly tightened terminal.

Small 'electrical screwdrivers' often don't allow you to apply enough torque to tighten a teminal screw properly.

If you fit a relatively small single wire into a relatively large terminal, you may need to double over the end so there's sufficient copper under the screw for it to grip properly.

 

[Gobo]

Strange one, the light fitting isn't wobbling at all when you turn it on? This could work the wire loose over time. The other thing could be the the screw your tightening could of lost its thread (possible when over tightened) and may hold for a short while before getting loose and allowing the wire to come free.

All I can suggest is removing the fitting and having a look at the thread etc.

Gobs.