Ask Electrical Question
E Books
Store
Blog
Subscribe

Adding an Outlet Or a Receptacle From a Switch Box

I get many questions regarding adding an outlet or a receptacle from a switch box.  This question comes up fairly often, and causes a lot of frustration for our visitors.  Here is the most recent question on this subject:

Question:

The power is connected to my light and then to the switch with #14 wire.  Black white and ground. I want to add a receptacle, how would I wire it from the switch? I want to run wires from switch box to receptacle box?

Answer:

You cannot wire this outlet by connecting it to the switch box in this situation.  This light outlet and switch are wired as a switch leg drop, and this leaves you without a neutral wire at the switch.  Let me show you with a diagram.

Power in to light, switch leg to switch

Note that the power comes into the light fixture outlet box.  The neutral is connected to the light fixture only.  The hot (black) wire coming in is spliced to the white wire going to the switch (and is identified as such with black tape or felt marker as shown).  The switched power comes back to the light fixture outlet box on the black wire of the 2-wire cable, and is then connected to the black wire (s) of the light fixture.  The position (on or off) of the switch turns the light on or off.

Now you can see that to attempt to add an outlet or a receptacle from this switch box will not work in this particular situation.  You don’t have the neutral conductor that you need for a receptacle outlet.  The only way you could do this would be to change the 2-wire cable (from the light to the switch) out to a 3-wire cable.  If this is not possible then the new receptacle would have to be connected from the light outlet box by running a 2-wire cable from light box to new receptacle outlet.

Power in and out of light, switch leg to switch

Remember you need to identify the white wire as being used as a hot conductor by use of black tape or felt marker (not shown in this diagram, but shown in diagram above)

Of course you need to check how many outlets are on this existing circuit before you add any outlets to avoid overloading of the circuit.

If the power comes to the switch outlet box first, and then to the light fixture, you could add a receptacle from the switch box in that situation.

Thanks for the questions!  Keep them coming!

- Terry Peterman, the Internet Electrician

This entry was posted in Home Electrical How-To, Q & A and tagged , , , , , , . Bookmark the permalink.
  • Philip_battisti

    This is not totally true. If you just want to use the outlet for a night light you can run your wires straight from the switch to the outlet. only when incandescent lights are used. As long as the bulbs are good the night light will come on when the switch is off only.

  • NEPA_DIYer

    I want to install the box itself in a finished wall. Nowhere on your site do I find the “carpenter” instructions for cutting the hole or installing the box itself. You seem to always assume that part is done… Where is the detail for installing the work box(es), fishing the wires through a wall, etc.?

    • Philip_battisti

      go to the lowes or electrical distributor and but an electrical box made of plastic. these new boxes have the wings that fold out to the side when you tighten up the screws. before you put the box in you first have to figure out where you are getting your power. If you are getting it from a basement you can drill up into the wall from the basement, measure very carefully, so you do not miss the wall.Write me back to let me know how you are getting your power from.

  • darkNiGHTS

    Thanks for the clear explanation.

 

The Basics of Household Wiring DVD

"If you're looking for a good reference to help you understand simple home wiring, I personally recommend 'The Basics of Household Wiring' DVD".

Terry Peterman, the Internet Electrician
 
Electrical Wiring
Electrical Diagrams
Projects
How To
Electrical Tools
Electrical Videos
Copyright © www.electrical-online.com |  LEGAL DISCLAIMER |  PRIVACY POLICY