There are a variety of reasons why you may need to dig trenches or holes in your yard. One thing you can face is the number of utility pipes and wires running through your yard at various depths. If you accidentally catch one of these, it can cause harm and be costly. Because so many cables and pipes are running underground, you need to be careful when digging.
Before you start, you’ll need a good idea of how deep residential power lines are buried. In our guide, you can learn how deep utility lines are buried in your yard and where you go to find such information. (Read Electric Stove Wiring Requirements)
By the end, you’ll have a much better understanding of how deep electric lines are buried. So, you can complete your home renovation.
How Deep Should Electric Lines Be Buried?
Are you curious as to how deep underground power must be? Are you having a trench dug and need to know the depth? That is something we can assist you with. Underground electricity lines should be at least 3 feet deep to the top of the cable or conduit.
Because you’ll almost certainly need to employ someone to dig a trench and go all the way down. Most utilities install underground electrical lines with considerable insulation. National Codes specify the depth to which these lines must be buried below ground.
Some low-voltage underground wiring may be as shallow as 18 inches, whereas higher-voltage primary lines are at least 24 inches deep. Many utilities are members of groups that map and record the locations of ALL underground lines, such as electricity, cable, phone, and gas lines.
The utility provider or an underground records firm can come to your home and mark the locations of underground lines so you know where they are.
Does underground electrical wire need to be in conduit?
If you need to bury eclectic cables for a garden pond or water feature, then you need to follow the rules. Most states require electric wire to be buried inside conduit. Having underground power connected to old power lines from a house, garage, or building on your property will require more modern wiring.
Other types of underground wires are direct burial and tech 90 cables. The electrical utility will feed conductors to the building’s basement and link them to the equipment so they won’t influence other electrical services or fire protection systems.
How Deep Are Most Utilities Buried?
To map all the underground utility lines, you’ll find the utility companies use a company to map and record such things as underground power, water lines, and possibly gas lines.
So, your local office should be your first contact if you are doing any construction. (Learn How To Dig A Trench For Electrical Wire)
Reasons to Call 811 Utility Marking Services
- Building a garden pond
- Planting a tree
- Digging yard to install a sewer trench
- Digging post holes for a fence
- Digging foundations
- Searching to install an irrigation system
- Laying conduit for exterior outlets or lights
When a marking service visits your property, or you contact them for copies of the recorded cables and pipes, etc., some utilities are marked, and others are not.
- Electrical service cables
- Cable TV or internet wires
- Telephone wires
- Sewer and water mains
- Natural gas pipes
- Security systems
- Lawn irrigation systems
- Landscape lighting systems
- Electrical conduits or underground cables for pools, etc.
The depth to which these utilities must be buried varies by region, and in colder climes, sewer, and water lines are frequently buried deep in the earth and below the winter frost line.
How to Find Utility Lines
A utility line’s start and end points can find its general position. To find a water line course from the street to your house, see where it enters your yard by the water meter. Find the water line’s entry point to your home and imagine a straight line between the two spots to see where your water line runs. It is a tough guide, but not always the case.
Call 811 to be sure of how deep utilities are buried.
Utility Line Color Codes
- Red: Electric
- Yellow: Gas, oil
- Orange: Communications (telephone/ internet), alarms
- Blue: Potable water lines
- Purple: Reclaimed water, irrigation
- Green: Sewer
- White: Proposed excavation
- Pink: Survey markings
Limits of 811 Utility Location Service
The free 811 coordination service marks the location of utilities up to where the lines join to the home or service meter. If lines continue underground, such as from a house to a garage or shed, 811 does not pinpoint their location. These secondary lines are considered the owner’s property, not the utility companies.
The 811 utility location service only detects underground services, and 811 won’t include municipal power reaching a property through the service drop. Contract companies that have buried underground pipes or wires. You’ll need to ask them for help, and this service may cost you. (Learn How To Connect Flexi Hose To Copper Pipe)
How Deep Do They Bury Cable And Power Lines In A Residence?
Do you wish to power a garage or a garden pond with electricity? This section contains more information regarding code requirements and the many options for trench depth, conduit material, and electrical cable type.
Installing an Underground Power Line
You have four options to run power lines underground through your yard. Your decision is based on how much power you desire. It also depends on your soil type and the site you wish to dig.
If the site is sandy and easy to dig, save money by searching deeper; you may not need to use conduit. Keep your site digging to a minimum if the soil is rocky or clay.
Regardless of the method you use, include a service entry bell that comes with a removable cover. Using these, you have access to the interior wires above ground level. Generally, before digging, you’ll need to be covered by a permit and check with an inspector about local construction codes.
Electrical Cable Depth Options
Figure out how much digging you’re prepared to undergo, as this determines the type of wire you’ll need installed around your house. Depending on the conduit and wire used, you can deploy underground cables to transport electrical power at varying depths.
Use galvanized rigid metal electrical conduit with individual conductors inside for a 6-inch-deep trench. Direct-bury GFCI-protected underground feeder cable with a short length of PVC conduit at the home for a 12-inch-deeper channel.
Inside one length of PVC conduit, use THWN-2 conductors to protect wires through the 18-inch deeper trench. For example, you can use underground feeder cable buried at 24 inches or PVC conduit at 18 inches below ground where the wire comes up. (Read Should I Buy A House With Radon Mitigation System)
1. Bury in the Ground: Dig Depth of Six Inches
Individual conductors should be run within a galvanized metal rigid electrical conduit (1/2-in. dia. is large enough for the water feature) at a depth of 6 in.
Waterproof conductors are required; thus, look for a “W” on the label, such as THWN-2.
2. Bury in the Ground: Dig Depth of 12 inches
Use direct-bury UF-B (underground feeder) cable at a depth of 12 in. if it fits three criteria:
- Before it enters the ground, it is protected by a ground fault circuit interrupter (GFCI).
- It is restricted to 120 volts
- It is only protected by a 20-amp fuse or breaker.
4. Bury in the Ground: Dig Depth of 18 inches
Inside the PVC conduit, run THWN-2 conductors 18 in. deep.
This method may be used to run any size circuit, so it’s an excellent answer if you want to power something other than a water feature, for example.
5. Bury in the Ground: Dig Depth of 24 inches
Direct-bury UF-B wire cable at a depth of 24 in. One stipulation: the main lines must be exposed outside your home and 18 inches below the ground level.
Because burying the cable 24 inches requires further digging, this method is only feasible if the soil is easy to dig or if digging equipment is rented. (Learn How To Remove Glue From Engineered Hardwood Flooring)
How ‘Call Before You Dig’ Works
Before digging, you must call 811 since 2005. Regional services can use this number to find underground public utilities nationwide.
Here is a step-by-step breakdown of the process:
- Call 811 at least three days before you dig; depending on your location, this timeframe may vary.
- Your call is transferred to a central call center, where you will be interviewed regarding your excavation project. The call agent then notifies any public utilities that might be affected by your digging and asks them to come out and mark utility lines.
- The utility company then dispatches technicians to your location to paint or flag underground utility pipes or wires. On these ground marks, color codes reflect different utilities:
Using 811 marks is advised, although they are only good for a month. Mark all utilities before you dig, and if you have to postpone your job for a month, call 811 to resume the process.
Digging Around Installed Utility Lines
Knowing the depth of various utility lines before digging to lay cables or planting trees will help you avoid them.
- Water pipes are buried 12 inches deep on average. However, some are buried 12 inches below the frost line.
- Phone and cable lines are buried at a depth of around 12 inches.
- Natural gas and electricity pipes have been buried at least 24 inches deep.
Keep a distance of about 15 inches on either side of the utility lines once discovered. This is because the instruments used to detect utility lines are unreliable.
Even in severely cold places, sewer lines do not freeze, but they must have a slope, so the depth varies widely, and the depth also depends on the depth of the street sewer. Most plumbers have equipment that allows them to find and record the depth of house sewers at regular intervals.
You can’t rely on any prescribed depth since landscaping frequently changes the slope above the services from the initial installation depth. All utility companies in the United States require the location of gas, electrical, and phone lines before excavation. (Read Utility Company Destroyed My Yard)