Diagrams for light-switch-wiring for new homes

A good house design plan includes light switch wiring for interior light fixtures and bath fixture lighting. Also kitchen lighting, office lighting, dining room lighting, and family room lights.We’ll also talk about 3-way light switches and show wiring diagrams for them and other circuits.

Home electrical wiring for lights is easy to install for simple lights that are controlled from one switch. 12-2 Romex is perfect for these types of lighting circuits.

Lights that are controlled from two or more switches are more complicated because they require 12-3 Romex and special 3-way switches.

The color of the wires is especially important, so you may want to squint at the drawings to better understand them.

The diagram below shows a simple single pole light switch diagram with the switch before the light in the circuit run.

Remember that the switch does nothing more than completes the electrical circuit when it is turned on. That’s why there are two hot (black) wires each going in and out of the switch.

light wiring diagram

The diagram below shows a single-pole with the switch behind the light. In this case, an extra hot wire is needed so it is legal to paint or wrap electricians’ tape around both ends of the white wire.

house wiring

Three-way switches are a little confusing at first, but after you look at the diagram and think it through, it’ll make perfect sense.

The easiest way for three-ways is to place the light between the two switches. You might have to go to an electric supply store for these switches.

3-way switch wiring

Another way is to put the light at the end of the switches as shown in the light switch wiring diagram below.

3-way diagram

Four-way switches sound confusing, but they are quite simple. Just remember this one thing: four-way switches are always between three-way switches.

You can have one light that is controlled from a dozen locations, but you’ll start with a three-way switch at the start of the light circuit, place ten four-ways in between, and then end with another three-way switch. Are you confused? Yeah, me too.

Many homes, especially those with garages, have lights controlled from many locations. You need to be able to turn the garage light on when you’re entering from outside, or entering from upstairs, or downstairs into the garage.

You will want to be able to turn the same light on or off from any surrounding part of the garage outside or inside. Any place where there is a doorway or entrance should have a light switch.

Three-way switches aren’t really “three way” at all. They’re only two-way if you consider that a light can only be controlled from two locations with three-way switches.

I don’t know where that word came from, but if you need to have a light controlled from three locations, you will need to start with a three-way, put a four-way in the middle, and end with another three-way. See the diagram below.

4-way diagram

Next, dedicated appliance circuits

Recessed lighting how-to

Back to electrical main page

Over 4 million visitors to this site since it was born!

My newsletter keeps you up to date on home construction and design ideas.

home construction

I just wanted to say that I love your website. My husband and I followed your instructions on building our own home. Most of the work we did ourselves, but not all. We saved $90,000 in labor costs and now have a beautiful home that we own.

--Sue and Les Carrigan, Draper, Utah

I built my own home doing all my own labor. My house costs me around $70,000 for materials. It took me 8 months to build and is about 2,000 square feet. I didn't think I could do it, but your house web site encouraged me. I used all the info you had.

Thank you,

Benny Luis Lopez,

Gainsville, Florida

I can't thank you enough for your free information web site about home building. I was looking for Electrical wiring diagrams when I found your site. It was very helpful.

Steve Lundquist,

Little Rock, Arkansas

My wife and I lost our home to foreclosure but we kept a plot of land to start over. We are halfway through the construction of our house. Your website gave us hope to start over and build a house with low payments. We are in our late 60's but we find it rewarding to put so much effort into a project that will reward us for years to come.

Name respectfully withheld