Installing a through-cord switch gives you the convenience of turning your light off and on without having to reach for the on/off switch for your fixture. A through-cord switch can be installed on any lamp-style cord. It can also be installed on any location along the cord. Installing an inline switch is also a way to fix a light fixture in which the switch is no longer operating and cannot be repaired.
Slice through the membrane located between the ribbed and the smooth sides of the lamp cord, creating a 1-inch-long slit. Feel your lamp cords. In order to determine which side is hot and which side is neutral, one side of the lamp cord is ribbed down the entire length of the cord and is considered the neutral side of the cord. The smooth side of the cord is considered the hot side of the cord.
Cut the smooth (hot) wire in half at the centre of the slit you created. Use wire cutters/strippers and remove 1/4 inch of wire from each side of the cut you just made. Strip an additional 1/4 inch of insulation off of each end of the wire.
Remove the screws holding the rocker through-cord switch together. Remove the top of the rocker from the through-cord switch, exposing the wiring screws inside it. Thread the ribbed (neutral) wire through the switch and the beneath the screws and rocker toggle. Wrap the smooth wires around the left and the right screws located on each side of the rocker toggle, and tighten the screws.
Replace the through-cord switch top and secure it to the lamp cord by replacing the screws.
Make sure you are certain of the location where you are going to install your switch before you cut your cord.