How to wire electrical outlets in series

Updated February 21, 2017

Wiring a outlet in series is a basic project that will allow the homeowner to additional outlets, such as in a garage, without having to run electrical wires back to the service panel for a separate circuit. Wiring a new outlet to an existing outlet allows the new outlet to feed off the existing outlet. Simply locating an outlet and connecting the wiring to the bottom of the existing outlet and over to the new outlet will have you up and running.

Locate the existing outlet that you will wire to the new outlet, and turn its power off at the main service panel. Each of the circuit breakers are labelled to help indicate what outlets and lights they turn off in the home. Touch the electrical probe tester to the outlet, and if no light or sound emits from the tester, then the power has been safely turned off.

Loosen and remove the screw holding the cover plate over the existing outlet and set it aside. Loosen and remove the two screws holding the outlet in its box at the top and bottom. Pull the outlet out of the box, but leave the existing wiring attached.

Measure up 18 inches from the floor and mark the measurement on the wall stud with the pencil. Line up the top of the new electrical socket box with the mark, and using the screwdriver, screw in the included screws on the box into the stud to secure it in place.

Measure up 18 inches and mark each stud between the new outlet box and the existing outlet box. Drill an 1/2-inch hole at each mark.

Feed one end of the cable through the hole in back of the new box, and through each hole drilled in the studs as you work your way to the existing outlet box. Feed the end of the cable through the back of the existing outlet box and pull about 8 inches through the front. Leave about 8 inches of cable hanging out the front of the new box and cut away any excess wire.

Strip off four inches of outer cable sheathing off each end of the cable. Strip off one inch of insulation of each insulated wire at both ends of the cable as well. Using the needlenose pliers, bend a half loop in each of the wires.

Attach the new wiring to the existing outlet using the bottom set of screws on the outlet. Attach the black wire to the brass screw, the white wire to the silver screw, and the bare (ground) wire to the green screw. Tight each screw down onto the wire to lock them in place on the outlet for a good connection.

Push the wiring back into the outlet box, and reattach the outlet to the box, by insert the screws back into the holes and tightening them down. Replace the cover and tighten its screw down on the outlet.

Attach the new wiring to the new outlet using the top set of screws on the outlet. Attach the black wire to the brass screw, the white wire to the silver screw, and the bare (ground) wire to the green screw. Tighten each of the screws down.

Push the wiring into the outlet box, and insert a screw into the top and bottom holes and tighten them down. Place the outlet cover over the outlet, and tighten its screw down.

Turn the power back on at the service panel, and plug in a light to test for power at each outlet.


Never work on any electrical socket or cable, without first turning off all the power sources to avoid the possibility of serious electrical shock or electrocution.

Things You'll Need

  • Electrical probe tester
  • Measuring tape
  • Pencil
  • 110-volt electrical socket box
  • Screwdriver
  • Drill
  • 1/2-inch wood drill bit
  • 1 roll 14-2 gauge Romex electrical cable, 25 feet
  • Wire cutters/strippers
  • Needlenose pliers
  • 110-volt electrical socket and cover kit
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About the Author

Laurie Brown has worked as a high school English teacher for the last several years and loves writing. She enjoys helping her students develop a love and appreciation for writing, reading, and literature. Laurie has a degree in education with a major in English. Currently she is a writer for eHow.