ask the electrician
Electrician Training Electrical Certification wiring recessed light fixtures Electrical Wiring Electrical Troubleshooting and Electrical Repairs wire outdoor light fixture Home Electrical Wiring Diagrams
wiring home generator and transfer switch wiring a 220 volt range cord outlet Wiring for GFCI Outlets Wiring Outlets and a Switched Outlet Wiring and Installing Ceiling Fans and Remote Controls wire dimmer switch wiring diagrams for switches wiring a dryer cord and 220 outlet circuit breaker panel
Electrical Wire and Cable

Replacing a Light Switch and Changing the Wiring

How to Replace a Light Switch and Make the Wiring Connections, Identifying the Wiring, Connecting the Wiring for Your New Switch. How do I connect the wires when replacing my light switches?

© By:

Electrical Wiring Video

Home Electrical Wiring Videos about this Topic and More

Check out my YouTube Channel, and Subscribe!

Learn more with my Home Electrical Video Course:

Basic Home Electrical Wiring by Example

Wiring Light Switches
Electrical Question: How do I connect the wires when replacing my light switches?

I need to replace a single light switch, but when I pulled the old switch out of the wall here is what I discovered:

The switch has three wires attached to it, in addition to the grounding wire. Two of these wires are pushed into the back of the switch, the 3rd one is around one of the screws on the side. The new switch that I bought only has two screws, not counting the grounding screw. How do I connect this? I’m not sure if all three of the wires going into the old switch are “hot” or if only two are hot, which ones they are. What would that third wire be from? I also noticed on the old switch that it says “CU and CU Clad Wire only.” This means that I have copper wires, not aluminum, correct?

Thanks in advance for any help you can provide.
This home electrical wiring question came from: Dina, a Homeowner from Baltimore, Maryland.

Dave’s Reply:
Thanks for your electric wiring question Dina.

How to Replace a Light Switch and Make the Wiring Connections

Application: Wiring for a Light Switch.
Skill Level: Beginner to Intermediate – Best performed by a Licensed Electrical Contractor.
Tools Required: Basic Electricians Pouch Hand Tools and Voltage Tester.
Estimated Time: Depends on personal level experience and ability to work with tools.
Precaution: Identify the light circuit, turn it OFF and  Tag it with a Note before working with the wiring.
Notice: Installing additional electrical wiring should be done according to local and national electrical codes with a permit and be inspected.

Electrical Wiring for Light Switches

Identifying the Electrical Wires When Replacing a Light Switch

When Connecting the Wiring for Your New Switch, this is what I Recommend:

Electrical Wiring Abbreviations and Terms about Light Switch Wiring

More about Wiring Light Switches

Light Switch Wiring
Light Switch Wiring

Electrical wire

The following may also be helpful for you:

electrical wiring book

A Complete Guide to Home Electrical Wiring

Be sure to get your copy of my BIG Book:
Perfect for Homeowners, Students and Electricians
Home Electrical Wiring - Room by Room
120 Volt Circuits
240 Volt Circuits
Multi-Wired Circuits
Wiring Methods for Installing Home Electrical Circuit Wiring
Electrical Codes for Home Electrical Wiring
....and much more.

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

More articles about Electric Wiring, Light Switch Wiring and Home Electrical Wiring:
« Previous Next »
How to Install 3-Way RF and Smart Devices for Switching How to Repair Telephone Wiring Connections