It’s Electric

Well, now that the greenhouse is fully built, our vegetables are growing like crazy, and it’s as hot as it gets in Colorado, it is time to get back to my workshop build. I haven’t been able to get that much done since my last post, but I was able to tackle a majority of the electrical work this weekend. Because this is going to end up as a finished workshop, I knew I wanted to have plenty of outlets and lighting for the shed. After a bit of research and planning based on my needs, I decided to go with 2 outlet circuits, one 20 amp and one 30 amp. These two circuits will allow me to have multiple tools running simultaneously, i.e. a dust collector and a miter saw, and having the 30 amp circuit will allow for some higher power tools in the future if necessary. You aren’t supposed to use more than 80% of a circuit’s capability, i.e. no more than a 16 amp tool (or a 10A and a 6A tool at the same time) on a 20 amp circuit. Using this handy chart from Wood Magazine, it made sense to go ahead and run a 30 amp circuit.

Useful diagram from Wood Magazine

Before getting out the tools and going to work, I drew this great engineering sketch below. This setup means that I will always have plugs within 2 feet of anything that I am working on around the wall and a dedicated lighting circuit for as much lighting as I need.

The small boxes along the walls represent the 20A circuit with the 3 big boxes representing a double outlet with the 20A and 30A circuit sharing a box. Included is a dedicated 15A lighting circuit.

I’m not going to go into a ton of detail regarding electrical work here, but I have found that the book Wiring a House is fantastic for learning the details of wiring (check your local library). That book helped me to pass the homeowners electrical exam here in Denver, however, if you do not feel comfortable with wiring, hire an electrician.

Running a 20 amp and a 30 amp circuit meant drilling holes through the center of every stud for the wire run, and then running 12 and 10 gauge NM wire through the walls and into the 9 outlet boxes (12 outlets) spaced across the walls. The hardest part here was drilling the holes in the studs, as my drill didn’t fit in some of the spaces between studs. I ended up renting a right angle drill and using a long extension on my shank bit to get everything drilled as required.

Note all of the wiring run through the middle of the studs in as straight of a line as possible. Do not note the mess that is the workshop.
It is key to make sure you leave plenty of wire pulled through each box to hook up the outlet. Not having enough wire to connect the outlet is, from experience, very frustrating.

After running all of the wire to each outlet box, I connected each outlet. For both circuits, the first outlet I installed is a GFCI outlet. By wiring this in a direct connect manner (any power on this circuit runs directly through the outlet), the single GFCI outlet acts as protection for every outlet downstream. The rest of the outlets were wired using pigtails, meaning that the current does not run through every outlet in the circuit, only the ones in use (plus the GFCI).

Here is the GFCI outlet wired in a direct connect method. Both the incoming and outgoing lines are connected to the outlet directly (black = hot, white = neutral, copper = ground)
This is an example of an outlet connected via a pigtail. Unlike above, the incoming and outgoing wires are pigtailed together, with a 3rd wire going to the outlet.

Lots of wire stripping, twisting, screwing, and packing into boxes later, and all of the outlets were wired and in place.

Here’s a view of a few of the outlets wired up and in place. Connecting outlets is a straightforward but tedious process.

Now those of you more familiar with wiring may be wondering where these circuits will get power. In my diagram I outlined that it will be from the house, and in next week’s post I’ll go into how exactly I plan to do that and why I chose my approach. Thanks for reading and feel free to let me know if you have any comments or questions!

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