Light Switch Wiring Troubleshooting

Wiring a Light Switch – The types of Circuit Wires Typically Found in a Switch Box and How They are Connected, To Get Your Light Switches Working it is helpful to understanding that a light switch is basically the switching of a the power source as explained here with the help of Wiring Diagrams for Light Switches.

How Wire a Light Switch

Light Switch Wiring Explained
Electrical Question:  I am confused about the wiring of  a light switch.

• Here is what I have:
  • 1 outlet box with 3 lines coming in to it.
  • Only one line is hot and outlet box has one light switch for a bathroom light and one receptacle.
  • One wire goes to hall light switch, another wire goes to a bedroom receptacle.
  • All three lines coming into the outlet box are black, white, and ground.
  • I am not sure how to connect the wires to the light switch and still keep the the receptacle in the bedroom hot.

Received from Gilbert a Handyman in Sacramento, Calif.

Dave’s Reply:
Thanks for your electrical question.

How to Wire Light Switches

Preparations
Application: Wiring a Light Switch.
Skill Level: Beginner to Intermediate, best performed by a licensed electrician.
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 lighting circuit, turn it OFF and  Tag it with a Note before working with the wiring.
Notice: Installing additional electrical wiring for light fixtures should be done with a permit and be inspected.

Identifying the Circuit Wiring
It is very helpful to identify the wires and then organize them together into groups so you understand which wires will be spliced together and which wires will be attached to light switch.

Types of Circuit Wires Typically Found in a Switch Box and How They are Connected

• Cables and Wires
  A cable is typically a group or wires with one outer covering containing a black wire, white wire, and ground wire. This is commonly referred to a 2-wire cable with a ground.
• Power In
  This is typically the black wire of a cable which supplies the circuit power.
• Power Out
  This is typically the black wire of a cable which supplies circuit power out to other devices such as wall outlets.
• Wires to the Light Fixture
  This is the cable that goes up to the light fixture with the black wire that will be controlled by the light switch.
• Neutral Wires
  White wires are typically the neutral wires that are in the same cable as the circuit power wire.
• Ground Wires
  A bare copper wire or a green wire is the ground wire which is found in each cable.

Grouping the Wires Together

Once the wires have been identified, then the wires can be organized into groups that will be spliced together to keep the circuit connections, and the additional wires that will be necessary to connect the circuit power to the light switch.

The Power In and Power Out black wires are spliced together, and an additional wire is added to provide power to the switch. The Black wire that goes to the light fixture is attached to the light switch. All the White Neutral wires are spliced together. All the ground wires are spliced together and bonded to the switch and box. Note: Some switch boxes may have more than one electrical circuit cable, and these wires must be identified as well so they can be kept separate from the light fixture circuit wiring.

For More Complex Wiring for Light Switches
To Get Your Light Switches Working it is helpful to understanding that a light switch is basically the switching of a the power source as explained here with the help of Wiring Diagrams for Light Switches

• This type of question is hard to answer because it lacks a lot of clarification and there seems to be an explanation of a few missing wires. With me being placed right in the middle of something like this it creates all kinds of questions of my own.
  • My first question being what has taken place that caused all these wires to need to be identified, or what is the original problem?
  • Is this wiring that was just added that does not work?
  • If so you may consider contacting the person who added the wiring and ask them to put it together and make it work.
• I run into this from time to time where I am brought into a situation where I have to basically get out my testers, pencil and paper and identify what someone else has wired.
• If you’re working at a home that has original wiring, then 99% of the time outlet wiring is connected color to color except for switched outlets or 3-wire or multi-wire circuits.
• Wiring to a light switch is basically the switching of a hot wire and splicing the neutral wires that lead to the fixture.

How to Troubleshoot a Light Switch Wiring Problem
Troubleshooting electrical wiring begins with identifying the problem, asking a lot of questions, then start the process of elimination. Work the problem backwards starting with what does not work and travel back towards the source until you find the problem.

• Wiring a light switch can be challenging sometimes when there are many wires to try to figure out.
  • If you having a hard time wiring a switch then consider having a professional help you out.
• So many times Ive seen projects where homeowners hire someone who is not a professional just to save themselves money.
  • Most of the time they end up spending more because they end up hiring a professional to fix what was installed wrong.
  • This is not intended to speak bad about handymen and women, not at all. I know some who know more about electrical wiring than a general contractor, this is rare, but interesting to note.
• I know a lot of very knowledgeable handymen and handy women who provide a great deal of services to a lot of people at a very reduced rate.
• The key is to understanding when you may be getting into something that may be beyond your abilities. At that point it may be time to hire a professional to take care of it for you.

See More about Wiring Light Switches

Wiring Diagrams

Electrical Wiring Diagrams

Home electrical wiring diagrams are an important tool for completing your electrical projects. An electrical wiring diagram can be as simple as a diagram showing how to install a new switch in your hallway, or as complex as the complete electrical blueprint for your new home or home improvement project.

How to Wire a Light Switch

Troubleshooting Electrical Wiring

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. Complete Guide to Home Electrical Wiring Perfect for Homeowners, Students, Handyman, Handy Women, and Electricians Includes: 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.

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