Most sheds are where we store gardening equipment, but for some of us, this becomes a workspace. We look for ways to power are tools, or we want power for that window air conditioner. We need those electrical outlets, so we run power to the shed.
In my old home, the garage was my workspace; the shed was simply storage. The garage was large enough to contain two cars as well as my workshop. When I moved into my current home, the shed was larger, and the garage was small. It made sense to use the shed as a work space. Thankfully, this outbuilding had power. During my home inspections, I noticed that most homes do not have sheds. Maybe this is because most people have other people do their yard work? Still, I do encounter sheds, and about half of them do have electrical outlets. Usually, there is something wrong with these outlets. During one home inspection, I came across another problem with running the electricity to this workspace, so I thought maybe going over different problems with bringing power to an outbuilding would help those looking to create their own space.
My habit during a home inspection is to first walk around the home (inside and out). This gives me a sense of what I will be seeing, once I begin my inspection. I came to this one home where I spotted a conduit coming down on the right side behind the fence. Maybe the service panel (breaker box) was located there. I opened up the home. Going to the back door to unlock it, I saw a slab for a small foundation in the backyard. I went back out the front door to begin my initial walk around the home. The gate was on the right, so I headed to the left side first. I found the service panel there. Going back to the right side past the fence, I found the conduit was coming out from the attic, but nothing was in it. Looking down on the ground, I found an electrical cable. Looking back to the yard, I saw the slab, so I walked over to this foundation. This could have been for a spa. Clues made me think of an outbuilding. This is where the electrical cable ended. This set up was not connected to the panel, but I could see that it was wrong.
This electrical cable was not in a conduit under the ground, and it was not buried deeply. This is one reason why having an qualified electrician install the power to your shed, because they will know the local rules. What was wrong with this wiring were common mistakes: the conduit was not attached to the wall; and the cable under the ground was not buried properly. This conduit came out of the soffit straight down, about four feet from the ground. Conduits should be secured to the wall. This prevents damage to the conduit by movement (think equipment hitting the conduit). I realized by looking at the end of conduit that nothing had been attached to the end. This caused me to believe that the wire came out of the conduit to the ground. At the ground the cut cable was laying on the ground. This was not going under the ground till a few feet away from the end of the conduit. Back at the slab, the wire comes out of the ground a foot away from the slab. You will have to check your local codes, but in general, you will want the conduit to run all the way from the house to the outbuilding. Where ever the conduit is above ground, you will want the conduit securely attached to the building. Under the ground, you will want this conduit to be below the frost line in your area (anywhere from two to four feet can be common).
This was not the case at this home, but I do find other problems on a consistent basis. Double lugging happens frequently. If your breaker box has no more space for a new breaker, then you may consider adding the wire for the new circuit to an existing breaker. This is called double lugging, and this is not proper wiring practice. This can lead to electrical problems as well as fire. You need a new breaker for each new circuit (which you can think of as a run of wire). If there is no space for a new breaker in your box, then you need to have a sub-panel to accommodate the new circuit. Inside the shed, you should think of the outlets as if they were in a garage. This means that you will want them to be GFCI (ground fault circuit interrupter) outlets. You will also want them to be weather resistant (WR) outlet. This is a safety issue if the outlets come into contact with water, which can easily happen in this space. The other issue that I find during the inspection is that the outlets should be secured to the framing. The outlet should have a cover. Wiring connections should be in a junction box that has a cover. Lastly, the wiring between outlets and fixtures should be secured to the framing. These are all items that deal with safety, and in sheds we do not seem to think that this is so important, or we are not sure what to do. Again, this is where asking someone who knows your local code helps. You should apply for a building permit, so that you know that it is right.
Obtaining a building permit can be a hurdle, yet this may be your best option. At least then you will be secure. I have found having the ability to use my little shop in the shed as such a great benefit, so I feel bringing power to an outbuilding can be a benefit to anyone.