How to Run Underground Power to a Shed | Ask This Old House

Ask This Old House master electrician Scott Caron turns a shed into a powered-up hangout by running electricity underground.

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Time: 1-2 days

Cost: $4000-5000

Skill Level:
Difficult

Tools:
Trenching machine
Shovel
Propane torch
Concrete mixer
Hole Saw
Drill/Driver
Screwdriver

Shopping List:
1 ½-inch PVC conduit pipe
PVC junction boxes
UF 6-gauge electrical wire
UF 6-4 electrical wire
NM 14-2 electrical wire
Electrical wiring boxes
Breakers
Electrical Sub Panel
Masonry screws

Steps:
1. A project like this should only be performed by a licensed electrician.
2. Before digging, call the utility locating service to mark any underground pipes or wires.
3. Begin by digging a trench from the house to the shed. This can be done with a trenching machine or a shovel. The trench should be 18 inches deep to bury electrical conduit according to code. In some cases, you may not be able to reach that depth due to site conditions.
4. Spread out a layer of sand into the trench to protect the conduit from sharp rocks.
5. Lay out the lengths of 1 ½-inch PVC conduit to go from the house to the shed.
6. Use PVC cement solution to coat the inside of each pipe and connect them together.
7. To make the PVC pipe conform changes in grade, use a propane torch to heat the pipe and make it pliable.
8. Form the shapes needed and lay the PVC conduit in the trench.
9. Use 90 degree PVC fittings to connect the underground pipe to the side of the house and shed.
10. Use a drill/driver, masonry screws and clips to attach the pipes to the side of the house and shed.
11. Use a hole saw to carve out a hole to feed the pipe and junction box into the side of the house and the shed.
12. Add a second layer of sand over the pipe in the trench to act as a warning in case anyone accidentally digs in the area and then cover that sand with caution tape.
13. Mix concrete with water and cover any conduit that did not reach a depth of 18 inches due to site conditions.
14. When the concrete dries, back fill the trench with old and new soil.
15. Feed fish tape from one side of the PVC pipe to the other. This will be used to pull up the electrical wires.
16. Tie a thin rope to the fish tape at the opposite end and pull that back through.
17. At the shed, use electrical tape to tie the 4 individual UF, 6-gauge wires (2 hots, neutral and ground) and feed them back through the conduit.
18. Mount a sub panel in the shed and tie on a braided 6-4 UF wire.
19. Connect the individual wires to each braided corresponding 6-4 wire using insulated connectors in a junction box.
20. The ground wire and the neutral wire will terminate in different spots in the subpanel. Connect them to the appropriate terminal with a screwdriver.
21. Tie in both hot wires to opposite sides of busbar, allowing 120 volts to 3 different breakers on both sides.
22. Attach desired electrical wire boxes throughout the shed for lights, light switches and outlets.
23. Run 14-2 NM wires throughout the shed and tie them through electrical wire boxes.
24. Attach any desired fixtures in the shed or on outside and run wire as needed.
25. Tie in 14-2 NM wires from fixtures and receptacles into sub panel breakers as needed.
26. Turn off the electricity inside the home at the main breaker panel.
27. Connect both hot 6-gauge UF wires to new 60 Amp breaker inside main breaker panel in the home.
28. Connect the neutral 6-gauge wire to the neutral bar inside main breaker.
29. Connect the ground 6-gauge wire to to ground bar inside the main breaker.
30. Turn the power back on inside the home at the main breaker panel.

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How to Run Underground Power to a Shed | Ask This Old House

[jamesmartello]

I can tell you one thing I was as electrical contractor in the Chicago area and I’ve never seen a sand base and concrete and warning tape installed in any trench I’ve done or anyone else has done. We used either rigid, iMac or pvc where the local codes allowed. I’m not sure if anyone could afford the work to the garage if I had to do all those steps. The coolest part of the video was the pvc heater to bend the pvc. We used to use a straight propane torch. Maybe that’s why at 69 yrs old I’m forgetting some things because of the fumes that came off the pvc if you burned the out side of the pvc while heating if.

[joeny]

That's alot of confidence in your work to trench, run the conduit, glue it, bury it, cement it .... And THEN feed that wire.

[twes]

Perfect how to video... Renting a trenching machine today. Just need to learn how to become a master electrician...I should be done in 5-10 years. Wish me luck!

[bobloblaw]

If you don't have a long enough fish tape, I use nylon pull string, tie a piece of plastic bag to the end, go to the other end of the conduit and use a vacuum. Works 90% of the time, every time.

[jameshawkins]

I just got finished doing a project where I had to run wire underground but I was putting a GFCI outlet at 17 trees for Christmas lights for a children's hospital. He was lucky to use that machine, they didn't want use to ruin the grass so we had to roll back the sod. Was so much work but it was for the kids!

[danaharris]

Gives you a good idea what is involved, not every aspect is covered but when you think this is at least several days worth of work and the time to get inspections and they are trying to pare it down to 11 minutes I'd say that was a great video.

[clownhands]

I don’t know why but this video shows up in my feed once a year and I watch it every time

[Imacat]

I was expecting a small trenching machine...Brings out the mother of all trenching machines!

[tonym]

Never seen an electrician work so hard lol

[roncole]

“Pretty good sized trench digger” pulls out a whole bobcat.

[timm]

In industrial plants the concrete is normally dyed red so that it's obvious that it is electrical if it's ever dug up.

[TheMixmastamike]

He is my favorite electrician from the show

[therealnickroberts]

You guys have such a good YouTube presence. So glad cause I used to watch on PBS all the time and now I watch it constantly online. Really cool to see the program adapt to the times.

[Mikeb]

with that small 100A main service adding a few lighting circuits in the detached garage is feasible. Installing a level 2 charging station is a stretch

[monstersofthemidway]

After watching that video, I still have many, many questions that were not touched upon for example:
- Why PVC rather than RIDGID conduit?
- What schedule is acceptable for underground PVC?
- Required permit not mentioned (comment)
- Required county inspection not mentioned (comment)
- If only one circuit is needed to the out building, is 6GA wire still required?
- Is UF cable acceptable for all underground applications?
- Etc., Etc., Etc.

[Chopwoodcarrywater]

I've been watching this show for 20 years. I learn something every time.

[noampitlik]

I'm just glad the sand protected the conduit from shop rocks.

[garydahle]

I'm glad you mentioned the 8ft ground rod, (made electrode) I would have recommended it for the shed. Even if the NEC doesn't require it.

[lrodriguez]

all that work with some dim lights at the end

[ALTNEWSUSA]

I always use an insulated screwdrivers when attaching wires to a circuit breaker. Even though the breaker is off, it protects any contact with the charged electrified panel board.