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Electrical Wire and Cable

Why Are White Wires On My Light Switch

Why White Wires are Sometimes Used for Light Switches: Wiring Light Switches with White Wires

Home Electrical Wiring Video

How to Wire a GFCI Outlet
without a Ground Wire

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Wiring Light Switches with White Wires
Electrical Question: I am changing out a ceiling fan and wall switch.

Background: Bill, a Handyman from South Florida.

Dave’s Reply:
Thanks for your electrical wiring question Bill.

Why White Wires are Sometimes Used for Light Switches

At times, we still find in some older homes that White Wires are used for wiring light switches, and the light switch wiring method is different, however we also find White Wires being used today for wiring light switches however the method is entirely different.

More about Wiring Light Switches

How to Wire a Switch

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.

Electrical Wire for the Home

Circuit Wiring
Circuit Wiring

Electrical Circuit Wiring

This article looks at common 120 volt and 240 volt house wiring circuits and the circuit breakers that are installed identifying the types and amperage sizes used in most homes.

For Best Results Consult a Licensed Electrical Contractor.
Locate An Electrical Contractor in Your Area

The following may also be helpful for you:

Dave's Guide to Home Electrical Wiring:

» You Can Avoid Costly Mistakes! «

Here's How to Do It:
Wire It Right with the help of my Illustrated Wiring Book

Great for any Home Wiring Project.
  electrical wiring  

Complete Guide to Home Electrical Wiring

Perfect for Homeowners, Students,
Handyman, Handy Women, and Electricians
Wiring GFCI Outlets
Wiring Home Electric Circuits
120 Volt and 240 Volt Outlet Circuits
Wiring Light Switches
Wiring 3-Wire and 4-Wire Electric Range
Wiring 3-Wire and 4-Wire Dryer Cord and Dryer Outlet
How to Troubleshoot and Repair Electrical Wiring
Wiring Methods for Upgrading Electrical Wiring
NEC Codes for Home Electrical Wiring
....and much more.

Learn more about Home Electrical Wiring
with my Online Video Course:
Basic Home Electrical Wiring by Example

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

Electrical Tips to Help You Wire it Right

The Safest Way to Test Electrical Devices and Identify Electric Wires!

The Non-Contact Electrical Tester
This is a testing tool that I have had in my personal electrical tool pouch for years, and is the first test tool I grab to help identify electrical wiring. It is a Non-contact tester that I use to easily Detect Voltage in Cables, Cords, Circuit Breakers, Lighting Fixtures, Switches, Outlets and Wires. Simply insert the end of the tester into an outlet, lamp socket, or hold the end of the tester against the wire you wish to test. Very handy and easy to use.

The Quickest Way to Check for Faulty Electrical Wiring!

The Plug-In Outlet Tester
This is the first tool I grab to troubleshoot a problem with outlet circuit wiring. This popular tester is also used by most inspectors to test for power and check the polarity of circuit wiring.
It detects probable improper wiring conditions in standard 110-125 VAC outlets Provides 6 probable wiring conditions that are quick and easy to read for ultimate efficiency Lights indicate if wiring is correct and indicator light chart is included Tests standard 3-wire outlets UL Listed Light indicates if wiring is incorrect Very handy and easy to use.

Strip Off Wire Insulation without Nicking and Damaging the Electric Wire!

The Wire Stripper and Wire Cutter
My absolute favorite wire stripping tool that I have had in my personal electrical tool pouch for years, and this is the tool I use to safely strip electrical wires.
This handy tool has multiple uses:
The wire gauges are shown on the side of the tool so you know which slot to use for stripping insulation.
The end of the tool can be used to grip and bend wire which is handy for attaching wire onto the screw terminals of switches and outlets..

The wire stripper will work on both solid and stranded wire. This tool is Very Handy and Easy to Use.

More articles about Electrical, Troubleshooting and Home Electrical Wiring:
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FAQs Frequently Asked Questions and Comments

2 Responses to “Why Are White Wires On My Light Switch”
  1. Greg says:

    I was just reading this article as I also was going to switch out some old switches to more modern light switches. When I pulled out the existing switch I noticed I have 2 black wires and a white wire connected to the old switch. I tried to figure out the path of power but I wasn’t getting the readings I was expecting. The old switch had 3 screws on it. 2 light brass and 1 dark brass named “common”. The ground is screwed into the box so I understand that. The dark brass had the main power connected to it.

    I tried to find continuity to the light this switch operated but I could only find it with the white wire. The black wire from the light to the light switch did not make my meter beep so I am not sure where it goes. There is also some other things in that light box I am not understanding. The switch mounting box is made for a double light switch but only has 1 switch mounted in it. It looks like the previous owner of this house just put putty over the other half. But in that box there are 3 sets of wires going into the box, there are red and white wires twisted together, white and black twisted together, and actually the main power wire going to the light switch I am wanting to change which has a black wire, white wire and a little single lead wire going to this light switch twisted together.

    Why do I have white wires twisted with black wires, why is there a white wire going to this light switch? Do I have a 3 way switches in there?

    Thanks Greg

  2. Dave Rongey says:

    Hi Greg,
    From what you have described the existing switch is a three way switch. White wires are often used for switching, however the white wire should then be identified with black electrical tape or a permanent marker. If the wiring does not appear to be correct then the wiring should be traced out and identified and corrections made as needed.
    I hope this helps,