So when I originally thought of the idea of writing a blog, I was planning for it to be a way to describe some of the home renovations my husband and I were working on. Of course, life intervened, and I never got around to actually starting this blog until I suddenly found myself with nearly ten weeks off of work and a lot of time spent sitting around. By that point, however, I had priorities other than the house which is why there have been a number of posts about babies instead. Rest assured, I do plan to write up what we’re doing on the house as we actually get the time to work on it, but those posts will almost certainly be interspersed with a number of posts about what it’s like to raise twins. Feel free to skip the latter if you’re so inclined.

Thanks to some very generous relatives who helped out with the babies over the past few days, I have actually managed to get a bit of work done on the renovation—namely wiring the outside and kitchen lights. So I thought that it would be a good time to go over how I did that.

The first thing I needed to figure out was how much light I actually needed in the rooms I was wiring. Being an engineer, I expected this to be relatively simple. After all, surely someone has come up with a formula for light needs, right? Turns out, the answer is sort of. I searched online for awhile and found a lot of formulas that would calculate the wattage needed, but I thought those were rather silly since wattage will change based on the type of light used (more on that later). I even searched the library catalog, my typical go-to for hard-to-answer questions, and found a whopping two books on lighting (I am sure I probably could have found the information I wanted in a more general interior design book, but I was not looking forward to going through the dozens available to do so). Fortunately, one of the lighting books did have a formula to calculate light needs in lumens (it’s similar to this one) which I could use since I knew the lumens of the light bulbs we were planning to use and that was a measurement independent of their energy efficiency.

One of the first things you’ll notice is that there are different requirements for different rooms of the house. This made sense to me as you are doing different things in different rooms. For example, you want bright light in the kitchen so you can see what you are doing. You also want the brightest light concentrated where you will be working the most—like the countertops, the sink, and the stove. The living room can have more diffuse lighting in general though you do want more concentrated light next to seating areas for reading and the like (we accomplish this with lamps). In the end, here’s what we decided:

• Living room/dining room: three track lights evenly spread out along the wall for more diffuse lighting and a pendant light hanging over where we planned to put the dining room table
• Outside: Two double lights, one on each side of the deck (both are switched instead of being motion sensitive)
• Kitchen: Six recessed can lights centered over the edge of the counter on each side, a track light over each kitchen sink pointed down at it, and a pendant light over the island butcher block
• Bathroom: A track light above the sink (it’s a half bath, so it’s very small)

We will likely turn half of the unfinished downstairs into a bedroom eventually, so more to come on our light decisions there. For now, we are using it as storage/a workshop so it has two four-foot fluorescent lights. I do plan to add two ceiling boxes in the center of each side of the room and wire the fluorescent lights into those to make it easy to change to different light fixtures later if desired.

Once I had that figured out, I again put pencil to paper and drew out exactly where I wanted all the fixtures upstairs. I then spent a good deal of time trying to figure out how many switches I needed and what they would control. The answer ended up being more than I expected. You can see the final drawing to the right, but here is what we ended up with:

1. A switch for the outside lights
2. A switch for half the outlets in the living room (this was how the living room was wired originally but we had removed the switch in the renovation, so I put it back and continued that wiring with the new section of the living room—it’s useful for things like plugging in lamps that are now controlled by the switch)
3. A switch for the pendant light over the dining room table
4. A switch for the living room lights
5. A switch for the right half of the kitchen lights
6. A switch for the left half of the kitchen lights plus the light over the island
7. A switch for the light over one kitchen sink
8. A switch for the light over the second kitchen sink

As I said, a lot of switches. However, I wanted to keep most of these lights on the same circuit because they really don’t take much power, so there’s no reason to put each switch on its own circuit (except the living room outlet one—that’s a 20A circuit while all the lights are 15A). You just have to be careful when wiring so that you don’t have to do something strange like turn on the living room lights before you can turn on the light over the sink. So how do you accomplish this? There are two ways that I did so:

1. Put all the switches in the same box and have multiple wires exiting the box to the lights that switch controls. This is generally the more straightforward wiring method. Basically, you do the following:
   1. Bring in one 14/2 with power
   2. Using pigtails, connect the black (hot) wire to the bottom of all the switches in the box
   3. Run a 14/2 cable per switch out of the box. Connect the black wire from each to the top terminal of the relevant switch. This is the wire which will run to your light fixture.
   4. Using wire nuts, twist together all the neutral (white) and ground (bare) wires
2. Use a 14/3 cable. Basically, this has four 14 gauge wires instead of the three that a 14/2 has (yes, the ground does not count in the numbering—confusing, right?). Here’s how you do this:
   1. Still bring in a 14/2 cable with power
   2. Using a pigtail, connect the bottom terminal of the switch(es) to the black wire of the cable with power
   3. Connect the red cable to the top terminal of one switch and the black cable to the top terminal of the other
   4. Wire all neutrals and grounds together
   5. Now any lights powered by the red cable are controlled by switch one and any lights powered by the black cable are controlled by switch two. You can also connect either the black or red wire from the 14/3 cable directly to black wire from the incoming 14/2 cable. This will give you the ability to wire in something that you want always on (we used it for our skylights) or bring power to another switch box. If you do use this option, I would recommend setting a convention—say the red wire is always switched and the black wire hot so you don’t have to trace wires later if you forgot which is which.

In general, if the fixtures you’re wiring are in the same direction away from the switch, I would recommend the second option. Otherwise, I would go with the first, especially since it tends to be a bit easier to figure out what goes where. You can even get very fancy and combine both options if you need to. We did this in one case where we had two switches and also needed to run power to a couple skylights. In this case, we ran a 14/2 for one set of lights and then a 14/3 for the second set of lights and the skylight with the red wire switched and the black wire always hot.

Once you figure out exactly where your switches and fixtures go, the actual wiring is straight-forward. In general, you would use 14 gauge wire since lights are typically on a 15A circuit (you can put them with outlets in certain cases—basically, if the code does not specify the outlets need to be on their own circuit, but I generally prefer not to do so because it makes things simpler and lets you have all 20A outlets without needing to run 12 gauge wire for lights). I then just nailed up the octagonal fixture boxes everywhere I wanted a fixture to go, drilled holes in every stud between the switch and the boxes (by far the most annoying part), and ran the wire between the switch box/fixture boxes. We have not put any actual fixtures on yet since we have not finished the walls/ceiling, so expect more when we get to that stage.

Some lessons learned as we went through this process:

1. A ½” hole fits two 14/2 wires pretty easily. It can technically take a 14/2 and a 14/3 or a 12/2 and a 14/2 but it was tight. I’d recommend going to 5/8”.
2. For ceiling fixtures, check the weight that the boxes you’re using can hold. Most of the cheap plastic ones can’t hold heavy fixtures, so you may need one that has extra support for things like fans.
3. Switches have an amperage they’re rated for. For those of you who have done electrical before, this may be obvious but I did not even think of it until I tried to wire a switch for 20A outlets.
4. Don’t trust the gasket for outdoor lights. Caulk around them really well.
5. Try to drill your holes in the center of studs. You need 1¼” of space from the edge of the stud to the wire (or a steel plate) so it’s just easier to drill through the center.
6. You need support wires within 12” of boxes and then every 4.5 feet. A hole through a stud counts so you only really need to worry about this if you’re running the cable in the direction of a stud.

That should hopefully get you started if you’re doing some lighting circuits of your own (and maybe make up for all those baby posts).