How Much Does Underground Electrical Service Cost?
Very few improvements can improve the look of both your home and your neighborhood than removing overhead wires. Whether you’re remodeling your home or working on a different project on your property, it may make the most sense to dig a trench and bury existing wires or upgrade your current services. However, underground lines can be costly and you’ll likely end up spending thousands more on this job than overhead lines, plus the few days of labor to dig and fill the trench.
The cost to run electrical service underground varies considerably from project to project. Though, you’re looking at somewhere between $4,500 and $20,000, depending on how far and how long the wires must travel underground. In other words, the price to install conduit for utilities is $8 per foot on average, including labor, equipment, trenching, and installation. Whereas, the cost of half-inch non-metallic PVC pipe conduit will add an extra $0.25 per foot.
Many homeowners also choose to upgrade their electrical service at the same time (from 100 Amps to 200 Amps, for example) which will require a new electrical service box and some additional electrical work inside the home – adding to the overall costs. Aside from costs, there’s a lot that goes into running underground electrical service.
Benefits of Underground Electrical Service
Choosing to install underground electrical service not only avoids those unsightly overhead power lines, but it also means you’ll no longer need to have a meter installed at the front of your house. Here are some of the benefits you can expect from installing underground electrical service on your property:
- One trench will do it all: Gas, electricity, and even telephone and cable service are often installed in the same trench.
- Power reliability: With underground service, power outages from storms and fallen trees are less likely.
- Reduces the danger of live-wire contact.
- Enhances curb appeal: Installing underground service removes overhead wires that can be a major eyesore.
- Decreases tree pruning costs that are necessary for overhanging wires.
- Fewer penetrations that go into your home, reducing areas where water and insects can get in.
Are Underground Power Lines Better?
Although buried power lines are protected against wind, ice, and tree damage that commonly result in outages, they are more vulnerable to flooding. Underground lines can also fail due to equipment issues and lighting. So, with that said, there are benefits and drawbacks to both underground and overhead power lines.
Video: DIY Underground Electrical Service
Before any electrical service can be run underground, it’s important that you understand the right cable to use. Underground electrical wiring can be installed in a raceway or directly buried. Experts suggest that the only cable that should be used is known as UF, or underground feeder, cable. This type of cable is outfitted with GFCI protection.
For UF cables, there are two main types of conduits that can be employed: galvanized rigid metal and Schedule 40 PVC. The latter is the most common option, as it is cost-effective and finished with a PVC cement. PVC conduit must be buried at least 18 inches deep, or 12 if it’s going to be covered by concrete.
If you must dig a shorter trench, galvanized rigid metal electrical conduit can be used, with individual conductors inside. These conductors have to be waterproof, so make sure you look out for those with a “W” on the label. THWN-2 wire, for instance, is a standard option for running through underground conduit. However, most people use PVC conduit for running electrical service underground, which may be direct-buried or encased in poured concrete for mechanical protection.
Trenching & Conduit Installation Costs
Whether you’re installing electricity, gas, water, sewer, or cable underground, a trench must be dug. This trench also provides drainage and forms the footing for the foundation. Of course, the type of conduit and the size of the trench needed will vary based on the type of project.
It’s highly recommended, however, that you hire a licensed professional for most ditch projects, especially when utilities are being installed. While you’ll spend slightly more money upfront, you avoid spending more on costly repairs down the line. Fortunately, most contractors will handle the digging of the trench for the electrical system they are installing.
To put things into perspective, the table below outlines the average costs per lot for some common home projects that require a trench. These costs include labor, equipment, support materials, and cleanup.
|Project||Cost Range Per Lot|
|Drainage||$1,900 to $5,100|
|Water||$600 to $2,400|
|Electrical||$600 to $2,400|
|Sewer||$1,400 to $4,600|
|HVAC||$3,800 to $7,200|
|Gas||$300 to $800|
Underground Electrical Conduit Installation Cost Per Foot
The cost to install conduit for electrical service averages about $8 per foot, including labor, equipment, trenching, and installation costs. Although, some claim that costs could be between $20 and $40 per foot, depending on where you live. In highly urbanized areas, the cost to run underground electrical service can be 10 to 14 times more expensive than overhead service.
While there are a couple of different types of conduit to choose from, PVC is the most commonly used and also the most affordable. Half-inch non-metallic PVC pipe will add about $0.25 per foot, bringing the total costs to install underground electrical conduit to approximately $8.25 per linear foot.
Electrical Trenching Costs
The cost to install electrical wiring or a panel are usually between $600 and $2,100. However, the size and layout of the project has a significant impact on the total cost, which could be as much as $20,000. Even if the project is on the smaller side, you should always consider hiring a licensed electrician. Depending on where you live and the scope of the project, most electricians charge between $50 and $100 an hour.
Home Projects that Require Electrical Trenching
Aside from simply running electrical underground to service your entire home, there are a number of home projects that require electrical trenching. Here are some examples:
- Surveillance cameras: The cost to install a security system is approximately $1,400.
- Indoor/ outdoor outlets: Homeowners pay $200 on average to install or replace electrical and ground-fault circuit interrupters.
- Lighting: Installing a lighting fixture costs an average of $460.
- In-ground swimming pool: Installing an in-ground swimming pool costs an average of $48,500, for a typical turn-key package that includes the electrical system required.
- In-ground hot tubs: These range from $15,000 to $20,000, including the trenching, electrical, and plumbing work needed.
Trench Digging Considerations
Installing electrical service underground means that a trench has to be dug from the power source, or utility pole, to your home’s electrical meter location. If you choose to handle the digging yourself, it’s crucial that you follow the technical standard established by your state jurisdiction, electrical code. The trench will also have to be inspected prior to filling it back in, to ensure that it is deep enough and that the appropriate number of conduits was installed correctly.
Before any digging can begin, it’s important that existing underground utilities are located. You can do this by calling dig-safe or dialing 811 to be connected to your local service. This service is free and they will come out to locate and mark your underground utility wires, gas, and water lines. This helps you, or your contractor, avoid damaging existing utility equipment underground while digging.
Depending on the soil type that your home sits on and the amount of power you’re planning on running, digging methods may vary. For example, if the ground is sandy and easy to dig, you can dig a deep trench. Whereas, if the ground is clay-based or especially rocky, you should keep the trench’s depth to a minimum. Regardless of the digging method you choose, it’s important that a service entrance ell be installed. This ell will feature a removable cover that allows easy access to the wires at ground level, when needed.
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Local Code Requirements
In addition to locating existing underground utilities, you should always consult your local codes and contact your local utility company to discuss the project with them. For instance, if you need to run conduit under a driveway, a structure, or anywhere that may have vehicle traffic traveling, there are specific conditions you have to follow.
If you’re simply digging a trench on your residential property for your single-family dwelling, here are the main requirements to keep in mind:
- Direct burial cables or conductors have to be 18 inches deep.
- Rigid metal conduit or intermediate metal conduit must be 18 inches deep.
- Non-metallic raceways that are listed for direct burial without concrete encasement or any other approved raceways must be 18 inches deep.
- Residential branch circuits rated 120 Volts or less, with GFCI protection and max over-current protection of 20 Amperes must be 12 inches deep.
- Circuits intended for control of irrigation and landscaping lighting, more than 30 volts and installed with Type UF or in another identified raceway or cable must be 6 inches deep.
- If the trench is dug through a rough, rocky terrain, the conduit has to be bedded using a minimum of 4 inches of sand.
- All conduits should be gray Schedule 40 electrical PVC.
Extending Existing Circuits or Adding New Circuits
Although it’s technically possible to extend an existing house circuit by simply running another cable to a garage or outbuilding, most local Code requirements state that you have to run one or more new circuits. Here are some standard requirements to keep in mind:
- For running overhead lighting fixtures and one or two wall outlets in an outbuilding: install one 15- or 20-amp 120-volt circuit.
- For operating a small workshop with 120-volt tools, install two 20-amp circuits.
- If you plan on running many tools or one or more that’s over 240 volts, you’ll need an electrical subpanel installed in your outbuilding.
Extending a current circuit to a garage or other outbuilding should only occur when the current circuit already serves a deck or outdoor outlets. You also must ensure that the new lighting fixtures and outlets in the garage do not exceed the circuit’s capacity. Before you consider this project, make sure that a simple circuit extension is permitted by your local Code.
How to Run Underground Cable
For this example, we’re going to describe the process of running Schedule 40 PVC conduit underground with UF cable or individual wires inside of it. The process is relatively similar for direct-burial of UF cable or if you choose to opt for rigid metal conduit instead.
- Using a garden hose or rope, create a pathway for the wiring you plan to run on the ground from your house to the garage. Always choose the shortest, most direct route whenever possible.
- With a trenching shovel start digging a narrow channel from your house to the garage at the recommended depth for the installation that you are doing. If you have to dig an especially long trench, you may consider renting a trenching machine.
- If you have to cross sidewalks, dig the trench to the required depth on both sides, and create a lateral hole underneath the sidewalk by driving a piece of conduit or pipe horizontally. Then, run the conduit through the hole you created.
- Position the conduit in the trench, using PVC solvent glue to weld the joints of individual sections. At each end, connect sweep fittings to vertical lengths of the conduit that extend upwards out of the trench.
- Place a fish tape down through one end of conduit to the opposite end. Connect the end of the UF cable (or individual THWN wires) to the end of the tape. Then, carefully pull the cable backwards through the conduit. It’ll make the job easier if you have a helper to feed the cable on one end as you pull the tape on the other.
- Allow for plenty of excess cable on each end of the conduit run. This will allow a licensed electrician to continue the necessary hookups in your home and garage.
- Before you back fill the trench, it must pass an inspection – if required by your local Code. An inspector will come out to verify that the conduit is buried at the proper depth and give you the approval to continue with filling in the trench and installing the circuit.
At this point, you’re ready to extend the cable into your home and garage, completing all the hookups.
Jessica considers herself a home improvement and design enthusiast. She grew up surrounded by constant home improvement projects and owes most of what she knows to helping her dad renovate her childhood home. Being a Los Angeles resident, Jessica spends a lot of her time looking for her next DIY project and sharing her love for home design.
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