Installing Electrical Receptacles in Your MiniMax Workshop

Outlets installed in wall
Receptacles installed in wall above workbench
Installing receptacles above worksurfaces in your MiniMax Workshop makes them easier to access.

As a follow-up to this previous post, once you have electricity supplying your workspace, it’s time to consider the placement of receptacles. There are a few considerations here. First, receptacles should be spaced close enough together to avoid using extension cords where possible. Secondly, consider the height above the floor for locating them. In your home, the standard height above the finished floor (AFF) for receptacles in the U.S. is 12″ (30cm). However, in your shop, figure that the average height of workbenches, table saws, and other worksurfaces averages out around 36″ (92cm). Most of the benchtop or portable hand tools that would be used in your shop will be on a workbench. Plus, floor space can quickly get crowded, often blocking lower receptacles.

For my MiniMax Workshop, I chose to install a two-gang receptacle box on every other stud in the walls. Since the stud spacing is 16″ (40cm) on-center, that makes a total of four receptacles located roughly every 32″ (81cm). For my way of thinking, it’s better to plan for more receptacles than you think you’ll need because you’ll, at some point, wish there was one closer to where you need it. Yes, I tend to go overboard on the number of receptacles, but I’ve never been sorry.

As for the height, I mounted all of the boxes 48″ (123cm) above the floor. This way, they would be easily accessible above worksurfaces and stationary power tools.

Here is my usual disclaimer. With anything involving electrical work, please consult with or hire a licensed electrician. If you’re running the cables yourself, they can advise on how the wire should be installed and fastened, what size wire to use, and how to make the connections. Also, cooperate with your local code officials and obtain the proper permits and inspections. It’s for your safety.

2-gang plastic electrical box with receptacles
Plastic electrical boxes will save you money but metal boxes are more durable.

I used inexpensive 2-gang electrical boxes that have a nailing flange on the front. I regret this decision. I found that the boxes can distort, making it difficult to fasten the receptacles and install the cover plate after the wall board is installed. And there’s always the possiblity that the plastic threads will strip. In the future, I’ll spend a little extra to buy metal boxes.

When it comes to running the wiring, I made another decision I sort of regret. Remember from this previous post that I ran two 20-amp circuits to the shop. My original thinking, and the way I wired it, was to dedicate one circuit to the recepactles on the north and west walls, and the other circuit to the east and south walls. The better solution would have been to run both circuits to each receptacle box. This way, each duplex receptacle in the two-gang box would be on a different circuit. This just helps even out the electrical load and prevent overloading in case you have power-hungry tools all along one wall. Again, this where your electrician can help you with how to do this per electrical code.

Another consideration, especially if your MiniMax Workshop is in a separate building, is whether to install outdoor receptacles. I took advantage of the open walls while I was running wires and poked through to the outside to install an outdoor-rated electrical receptacle box. I simply branched off the nearest receptacle box on the inside with the wiring. This outdoor receptacle has come in handy multiple times.

One of the things your electrician may mention to you is the use of Ground Fault Circuit Interrupters (GFCI) or residual-current device¬†(RCD in th U.K.) for the receptacles. In the U.S., they are required for circuits used outdoors, laundry rooms, bathrooms, basements, kitchens–anywhere there’s a potential for exposure to liquids. I could have used GFCI breakers at the main panel in the house. This would have protected both circuits going out to the MiniMax Workshop. But these can be pricey. Instead, I opted to install a GFCI receptacle at the start of each circuit then branched off to the other receptacles. This way, all of the receptacles downstream are protected.

After installing all of the boxes and wiring and making the final connections, it was time to flip on the breakers. This is always a sweat-inducing moment for me. But the worst that has ever happened to me is that I had a wire crossed somewhere and the breaker tripped immediately. If the breaker stays on, it’s a good sign your wiring is correct! To be sure, I checked each receptacle with a tester.

Testing the receptacles with a tester
Using a simple tester like this, you can verify that the wiring is correctly installed. A special GFCI tester is available that allows you to test that the GFCI operates correctly.

At this point, I called for my an electrical inspection as required by the local code officials. They looked at the breaker panel, the underground cable, and made sure I was using GFCI receptacles correctly. I passed the inspection which meant that I could insulate the walls and add the wall covering.

Adding Power to Your MiniMax Workshop

Electrical Power
Electrical Power
Photo by Pok Rie on Pexels.com

Unless you’re considering doing “unplugged” woodworking using only hand tools, you’re going to want some power in your shop. Even if it’s just for lighting, you need to consider how much power you’re going to need.

Let me stop right here and mention that I am not an electrician. I am comfortable installing breakers and running new circuits. However, I did consult with a licensed electrical contractor and the local code enforcement officials. You should do the same. They can tell you the requirements for cable size and type, breaker sizes, burial depth, and other important information. And certainly, if you feel uncomfortable installing wiring, receptacles, and circuit breakers, please–hire a professional.¬†

What I’m talking about below is the situation where you need to supply power to an outbuilding. If your MiniMax Workshop is in an attached garage or spare bedroom, simple talk to a licensed electrician about options for adding receptacles, if necessary.

Where electrical is required in an outbuilding, there are two solutions for supplying power. One solution is to branch off of the main breaker panel in the house and install a sub-panel in the workshop. This has the advantage of having only one higher-amperage breaker in the main panel to cut off power to the outbuilding when needed. Plus, you can install multiple circuits in the sub-panel inside the shop. This solution definitely requires the services and advice of your electrical contractor and code enforcement official to meet the necessary requirements for breaker sizes and quantity, cable size, and electrical grounding.

The second solution is to install separate breakers in the main breaker panel and run the appropriate sized cable to the workshop. This is the option I chose.

Main circuit breaker panel
Work with a licensed electrician to determine the size and quantity of breakers you need for your MiniMax Workshop.

For my MiniMax Workshop, I decided that I could get by with two 20-amp circuits. This would adequately supply the receptacles I wanted to install. Plus, I could branch off of one of those circuits for the lighting.

The problem was, my MiniMax Workshop shed is several feet away from the house. What would be the best method for running these two circuits to the shed? For my situation, the only workable solution was to run the cables underground that connected the breaker box in the house to the shed.

The first step was to apply for an electrical permit. This is required since I’m adding circuits to an existing panel. I had to specify that I was doing the work myself. In some areas, this is not allowed and a licensed electrical contractor must do the work or take responsibility for it.

The next thing you need to do is to call the utility service in your area to mark any underground cables and pipes. In my city, this is a requirement before starting any work that requires digging. The service I used painted the sod and placed flags to mark underground high-voltage wires.

Ground marked with paint and flags

With permit in hand, it was time to get to work.

To run wiring to an outside wall from the main panel, I had to fish cable up into the attic and over a laundry/utility room. The exterior walls of the house are masonry, so I opted to poke through the ceiling and run conduit down to a junction box that would connect to the outside. From there, I had to drill through concrete to connect to an exterior junction box. From the junction box to a narrow trench I dug, I used PVC conduit to protect the cable from weed trimmers and mowers.

PVC conduit connection
The box on the wall has a removable cover and connects to a junction box in the utility room inside the house. PVC conduit protects the cable that will be run to the MiniMax Workshop.

For my municipality, I had to dig a trench 18″ (45cm) deep between the house and the shed. The required depth where you live will likely be different.

When I reached the shop building, I again used conduit to run the cable up inside the wall. Then came the task of fishing the underground cable from the shed, along the trench, then up into the internal junction box in the laundry room. Inside, I completed the run using wiring rated for indoor use. Again, check with your code official and electrician for the proper cable to use outdoors and indoors.

Inspection tubes for buried electrical cable
Before covering the underground cable with soil, I installed temporary “view tubes” to allow the electrical inspector to verify the correct cable depth.

Before I covered the cable with soil, I installed “view tubes” or sections of pipe vertically in the trench that stuck above ground. These provided inspection ports for the electrical inspector to verify that the cable was buried at the proper depth. To prevent accidentally cutting into the cable in the future when digging, I also installed a yellow caution tape about 12″ (30cm) above the cable. This way, when a shovel hits the tape, it serves as a warning that there is a cable buried underneath.

Here’s where you may ask, “Why didn’t you run conduit the entire length of the trench?” Underground cable is very stiff and difficult to work with. I had enough trouble fishing it through the short lengths of conduit at the house and shed. The cable I used is rated for burial use without conduit, so it wasn’t an issue.

After this main cable was run, I connected it to the two new breakers in the main panel box. Then it was time to install receptacle boxes and wiring in the MiniMax Workshop. You can read more about that in another post.