Please note that some lamps that are made in sections have very small wireways at both ends of the tube and have large spaces between these holes. It is almost impossible to thread anything larger than a standard 18-2 SPT1 wire through them. If you take then apart (unscrew them) you will have better luck getting the wire through the holes. It is necessary to fully disassemble the lamp to feed the wire from the bottom of the lamp. Use a wire (thin but stiff) inserted from the top of each section downward and through the bottom hole. Strip a section of both conductors to allow you to attach the copper stranded wire to the stiff guide wire and pull it through. Do this for each section untill you reach the bulb holder. Cut off the stripped section that you used to pull the cord through and then correctly connect the lamp holder. If there is space make sure you use an Underwriters Knot to prevent tension from being applied to the lamp holder connections when you reassemble the lamp or when the cord is pulled...