Home wall outlets of the 110-volt variety connect with the 110-volt wires to complete a circuit. The electricity must flow from the circuit breaker through the wire to each switch and outlet on that given circuit, and once the electricity reaches the end of the circuit (the last switch or outlet) the unused electricity is then carried back to the circuit breaker. At each switch or outlet mounting receptacle in the wall, electricity is supplied by the wires on the left side of the outlet and continues on to the other outlets after it by flowing from the right side of the outlet. House wires are color coded black, red, white and bare copper, per wiring code regulations. These are connected to screws found on the outlet itself.
Turn off power, at the circuit breaker, to the circuit where you are installing your new outlet to prevent electrocution or death.
Pull the wires from the wall outlet receptacle so you may work with the wire ends easily. If the wire ends haven't been prepared for connection to your 110-volt wall outlet yet, use a pocket knife and carefully cut away the outer insulation from the wire bundle, being careful not to nick the insulation on the individual wires which are contained inside of the outer insulation. Cut away a 3-inch length of the outer insulation from both the left wire bundle and the right wire bundle. All of the interior wires should be completely exposed following this action.
Strip away, using a pair of combination wire strippers, 1 inch of insulation from each of the individual wires on both the left and the right wire bundles. The result should be 1 inch of bare copper wire at the tip of each of the wires.
Loosen all of the screws on the wall outlet with an appropriate screwdriver until extended fully, then orient the new wall outlet so that it is upright. The prong jacks on the front should have the two vertical slots on the tops and the single round (ground) jack below the two vertical slots. Visualize it's appearance such that the top two slots are eyes and the small round jack under is the nose. This is the proper orientation for any wall outlet. Hold the outlet in this orientation while connecting the wires to the outlet.
Gently press each wire over the top of each screw post, making sure the properly colored wires are connected to the correct screw post terminals. On most new outlets (but not all) the heads of the screws have paint on them in the color of the wire that goes to that post. If your outlet doesn't have painted screw heads, the National Electric Code requires the manufacturer to mold the terminal names into the plastic of the outlet body near each terminal. These markings or words will clarify: Red (hot), black (hot), bare copper (ground) and white (neutral). Connect the red wire to the positive (+) hot terminal and the black wire to the negative (-) hot terminal. Then connect the white wires to neutral, and any bare copper wire to ground. If your outlet is in the middle of the circuit, you will have to mate up the colored wires on each side of the wall outlet--left wires going to the left screws, right wires going to the right screws. There is only one copper ground wire which must be connected and both sides share this one wire.
Bend each wire around the screw posts, using needle-nosed pliers, so the wire ends form a hook around the screw posts. Do this for every wire and then use an appropriate screwdriver to tighten the screw heads until tightened down firmly onto each of the wires. Test your connections by pushing and pulling gently on each wire connection to ensure none of the connections are loose. If so, re-seat the loose wire and re-tighten.
Gently fold the wires into the recessed wall outlet box, pushing the outlet toward the box while folding. Continue doing this carefully until the metal mounting ears line up with the screw holes in the wall. Use the screws supplied with your outlet to fasten the entire outlet assembly against the wall firmly.
Place the wall outlet exterior cover against the outlet assembly which will hide the internals of the outlet. Use the screw provided with your outlet cover and screw it into the center hole of the cover until the wall cover is tightened firmly against the wall.
Restore power to the circuit and test the outlet by plugging in a lamp.