Filed under Electrical
Home » Electrical Wiring Directory » Electrical » Leave a Comment or Ask a Question
« How to Solve Window Air Conditioner Electrical Problems Adding a Sub-Panel to an Existing Service »

How to Extend the Wiring from a 3-Way Switch


By Dave Rongey - Summary:

The Key to Understanding Light Switch Wiring and Knowing What You Can and Cannot Do


White Wires and Light Switch Wiring

Electrical Question: I am trying to figure out how to finish my circuit. I have a 3 way switch controlling a light(in the middle) where the power(2wire) comes into the first gang box that has the leg going out to the light there. The other switch(on the other side of the room)has been wired to control this light as well using 3 wire. (The white coded as black). Using a double gang box for this second box, I’m trying to add an additional single pole switch and continue power to control another light, but I don’t know where this light’s white return wire should connect to, because the white in the box is coded for hot (black).

This electrical question came from: Jeff, from Richmond, Virginia
See more about Home Wiring for Virginia

Dave’s Reply:
Thanks for your electrical question Jeff

Understanding Light Switch Wiring

Understanding how a White Wire is used for light switches can be very confusing, and here is why:

  • Just because you see a “White Wire” in a switch box does not necessarily mean that it is a “Neutral Wire”.
  • It is often found that the White Wire is actually used for switching the hot, thereby being part of what is known as a “Switched Leg” which is nothing more than switching the hot side of the light circuit.
  • In years past and before the days of DIY home wiring, the white wire was used for switching and was not identified with black tape or a black marker which is now required. This was fine for us electricians because we understood this principle.
  • To complicate the issue, seasoned electricians know that long ago the neutral wire was used for switching light fixtures, not the hot wire. This practice was discontinued but every once and a while we still find this in some older homes, especially where there is knob and tube wiring.

The Key to Understanding Light Switch Wiring

  • What you can and cannot do will be based entirely on how the lighting circuit is wired and where the “Neutral Wire” actually is.
  • If you have not installed the electrical wiring then this is best discovered by using a voltage tester.
  • Once you have identified the location of the neutral wire you will then know if and how the wiring may be extended to accomplish your desired extension of the circuit wiring , or if it is even possible due to finished walls or available access.

How to Wire a Switch
electrical-switches

Wiring a Light Switch – Diagram 1

Wiring Diagrams

Fully Explained Light Switch Wiring Diagrams. Detailed Electrical Wiring Diagrams and Pictures assist your Home Electrical Projects.

Guide to Home Electrical Wire
electrical-wire

Electrical Wire for the Home

Complete listing of electrical wire types and parts used for home projects with electrical code information serves as selection guidelines.

Lighting For The Home

Lighting Electrical Codes


« How to Solve Window Air Conditioner Electrical Problems Ceiling Fan Light Not Working »


Learn How to Wire it Right with my
Complete Guide to Home Electrical Wiring
Perfect for Homeowners, Students,
Handyman, Handywomen, and Electricians
Includes:
Wiring GFCI Outlets
Wiring Home Electrical Circuits
120 Volt and 240 Volt Outlet Circuits
Wiring 3-Wire and 4-Wire Electric Range
Wiring 3-Wire and 4-Wire Dryer Cord and Dryer Outlet
Troubleshooting and Repair Electrical Wiring
Wiring Methods for Upgrading Electrical Wiring
Electrical Codes for Home Electrical Wiring
....and much more.

» Click here to learn more about Home Electrical Wiring «
  repair electrical wiring  


Be Careful and Be Safe - Never Work on Energized Circuits!
Consult your Local Building Department about Permits and Inspections for all projects.

Leave a Comment or Question

Thanks for your Comments and Quick Questions!

Please make sure your question is about the topic on this page, which is:
How to Extend the Wiring from a 3-Way Switch


Comments or questions posted here are open for Quality Discussion and Participation - Spam will be deleted.



*