If youre wiring a new switch youll need to install an electrical box. Heres how to do it without breaking the plaster and lath.

Howto Adding Two Exterior Lights Switch Piggyback New
Wiring a new light and switch. Probe the existing hole with a keyhole saw to find the horizontal edges of the lath. In this diagram a new switch and light are added to an already existing light switch. Because the electrical code as of the 2011 nec update requires a neutral wire in most new switch boxes a 3 wire cable runs between the light and switch. The source for this circuit is at an already existing light fixture and a 3 wire switch loop run from there to the switch box. How to install and use an electrical handy box how to strip the. Learn how to wire a light switch for new construction.
It can be anywhere but if you want it to be compliant with the americans with disabilities act put it 44 inches above the floor preferably near a door. Assuming it is a steel box. If the light switch has a ground screw on it usually green and at the bottom of the switch connect it now. First of all we should connect the ground wires to the box. If you put the loop over the screw in the counterclockwise direction tightening the screw will force the loop open and could create a loose connection. Adding new light fixtures off an existing light switch.
The red and black are used for hot and the white neutral wire at the switch box allows for powering a timer remote control or other programmable switch. Run a cable to the light fixture and another cable to the outlet from which youre drawing power. This is an updated version of the first arrangement. Fix old house wiring problems. Bring old light fixtures wired with knob and tube wiring up to code by installing an electrical box in the plaster wall. Wiring diagram for a new switch and light.
With the power coming to the switch and then going to the lights you will notice that there are two black wires two white wires and two ground wires bare wires. Wrapping the wire clockwise when wiring a light switch ensures that the loop on the end of the wire will tend to close when the screw is tightened. This 3 wire switch loop satisfies the nec requirement of a neutral in the switch box. This tutorial includes all the steps to wiring a light switch including. The easiest way to add new light fixtures is to run the new wiring to the existing light fixture splice the wires together as the old fixture was connected and then place a decorative blank cover over the fixture box.