How Deep to Bury Electrical Conduit | Bury Underground Cable (Updated) (2023)

In any home, there is likely at least one electrical service panel. Whether it’s a washer and dryer, a garage or some other utility, most homes have at least one electrical service box that powers outlets, switches and other fixtures. Because of this, the general rule is to run all electrical wiring — from the main service panel to individual appliances, switches and fixtures — through the walls of your home or property. This is called “burying” or “casing” electrical conduit. The only way to know for sure is to dig into the specifics of your situation so you can make an informed decision about how deep to bury electrical conduit. The right answer to which depth you need depends on several factors in your location and specific conditions in your home.

How Deep to Bury Electrical Conduit

In the case of a road or alleyway, the conduits must be at least 6 inches below the surface, and for a house, the conduits can be at a depth of 4 inches under a concrete slab or at a depth of 6 inches under a concrete slab.

Where the conduit will be exposed, the best way is to cover it with a concrete slab. This will make the conduit resistant to corrosion and prolong its life.

For conduits that will be exposed, concrete slabs are the best option. You can also install a conduit underground on a concrete or asphalt slab. The best option is to install a concrete or asphalt slab under the conduit. This is the best way to protect the conduit from corrosion and make it last longer.

Conduit materials vary, but they almost always include steel or copper tubing with screen or mesh screens at the ends. You may opt for PVC or polyethylene conduits, but these are less durable and should be avoided.

Make sure to appoint a trustworthy contractor to ensure you get quality materials and a job done right. You may also wish to consult an engineer or contractor to ensure your conduit system complies with local and national standards.

How to Bury Underground Cable

Four alternatives are available if you wish to bury an electrical wire in your yard. Your desire for authority will influence your selection. Additionally, the sort of soil you have plays a role. If the earth is sandy and you work it efficiently, you can save some bucks by excavating deeper (with any conduit). If the soil is tough or clay-like, minimize digging.

Ensure that you can open any approach you employ that has an entrance to access internal cables without leaving the ground level or a removable access cover. Before beginning any job, you must obtain permission and consult with the local code inspector.

Electrical Cable Length Options

Consider how much will you work to go deep before you start to determine the wire type you’ll need.

You can install an underground cable. You can do this for running electrical power to a remote location at various depths. This will relate to the conduit and wire used.

It would be best to fill a trench (6-inch-deep) with a galvanized electrical conduit with its conductors.

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In a 12-inch-deep trench, you can use a PVC conduit to direct-bury the GFCI-protected underground feeder cable.

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You can keep your wires safe by running them from your trench to your house using THWN-2 wires inside an 18-inch continuous PVC conduit.

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Using a PVC conduit, you can bury the feeder cable between 18-24 inches.

Bury in the Ground: Dig a Six-Inch Hole

To run the individual conductors at a depth of 6 inches, galvanized rigid conduit with a 1/2-inch diameter is sufficient for great performance (the water feature, for example).

Check if you find on the label a letter, such as THWN-2 or “W”. This is to ensure that the conductors are waterproof.

(Video) Conduit Burial Depth. Know the Code. On the Electricians in Action Everyday @ 9:00 am

You can use this method to operate circuits of any size.

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Metal conduit costs more than $1 per foot, which is inconvenient. You can take this path if your soil is tough to excavate.

Create a 12-inch hole in the soil.

Get a UF-B cable (underground feeder). It must meet three requirements, and you must bury it at least 12 inches deep:

Before it ever touches the ground, it has a ground-fault circuit interrupter (GFCI) protection.

Its limit is 120 volts, safeguarded by a fuse (20-amp) or circuit breaker.

We suggest this one if you need a short-foot deep solution (one foot) and does not require a costly pipe. It is the best way to power your water feature.

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To bury these conductors, which you have together with an 18-inch-deep PVC conduit, excavate 18 inches into the ground.

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This method allows you to run any size circuit, making it ideal for additional power items, such as a water feature and your water pump.

Burial necessitates a 24-inch dig.

Directly bury a wire cable (UF-B) at a 24-inches depth.

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For the cable you will bury outside the home and visible from the exterior, a conduit 18 inches deep is necessary.

DIY Underground Wiring

Preparation is the key to a successful underground wiring project.

Choose a 120v or 240v power supply for your residence.

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  • Determine if the main circuit breaker panel or a subpanel is necessary.
  • Check with the local authorities to determine whether you need a permit.
  • Contact the local utility companies and request if you need to mark any existing underground utilities.
  • The amount of manual labor or digging necessary will determine the type of wire you employ.
  • You must adhere to all municipal or community depth requirements regarding underground wiring. Remember that 18 inches of depth are typically enough for 240-volt power.
  • Additionally, the depth requirements for different types of wire and conduit vary:
  • 12 Inch Underground Feeder Cable (with GFCI protection)
  • Cable for underground feeding (UF Cable) – 24″
  • A rigid metal conduit contains 6 inches of electrical wire.
  • PVC Electrical Conduit Wire 18″
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(Video) The Easiest Way to Bury Cable Or Wire Underground

18-inch metal flexible conduit with electrical wiring. The work can commence after identifying existing wiring and selecting wiring for the project.

Dig a trench.

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  • Dig a trench as deep as your project requires to accommodate the selected underground wiring.
  • Renting a gasoline-powered trencher will reduce required labor.
  • Cut a hole through any interior walls with a power saw and a hole saw before connecting electricity. Hold with a diameter of 1 1/2 inches will suffice for most applications. Aim for a hold directly above the trench’s terminus.
  • Cut a plastic conduit with a 3/4-inch diameter to cover the bottom of the trench and the hole in the wall.
  • You may bend the conduit to fit the foundation using a heat gun powered by propane.

Set up a Cable Feed.

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  • Ensure the cable is long enough to reach the desired location when extending it from the electrical panel.
  • Insert a conduit outlet body made of plastic at the opposite end of the conduit.
  • After inserting a cable into the conduit, insert the cable’s opposite end into the wall opening.
  • The time has come to utilize the cable to reach the main electrical panel. If necessary, use joist hangers and cable staples to secure the line to the joists.
  • Run the cable through the trench to the desired location.
  • Repeat until you secure the plastic conduit and cable.

Maintain pipeline safety.

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  • The underground wiring project will proceed more smoothly if you secure the conduit.
  • After feeding the cable into the wall, you should attach the conduit outlet body to the exterior wall. Internally screw the second conduit body together.
  • Caulk the conduit outlet body with an acrylic-latex caulk designed for exterior use.
  • After covering the cable with 2 inches of sand, run caution tape along the length of the trench.

To complete filling the trench, use the excavated soil.

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A licensed electrician should make the final wire connections at the main electrical panel.

You can complete underground wiring projects quickly and affordably if you have a fundamental electrical theory and practice knowledge. You can always rent tools from Home Depot or utilize their electrical wiring installation services if the situation becomes too difficult. When you’re ready to shop, use The Home Depot Mobile app to have your purchases delivered directly to your door.

Underground Wiring Requirements

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The type of wire used will determine whether you need or not a conduit. This question is to achieve a particular objective, so let’s begin there. Regarding the depth at which we can bury electrical wiring. So, we have several options:

The grave excavation depth is 30 inches.

A feeder 24-inch-deep burial underground cable is enough for this case. You don’t need a conduit for UF cable at that distance. However, you must use a conduit for 18-inch vertical feeds.

18-inch depth is another choice

Think about installing PVC conduit conductors (THWN-2) only this distance (18 inches). This safeguards the cable if it is accidentally buried. THHN-2 is a waterproof variant of thermoplastic High Heat-resistant nylon-coated wires.

12″ is the maximum burial depth.

A 12 inches depth is enough to install GFCI- burial feeder cable wire. Cover any PVC in your residence or garage with PVC.

6-inch tomb depth

Only a 6-inch depth is required for buried EMT (metal electrical conduit) galvanized with its conductors. The EMT doesn’t care if you use a shovel or other significant object that can do wiring shorting.

Depth Requirements for Buried Electrical Cable

The most expensive method, but requiring the least amount of digging, is installing underground cables in metal conduits approved for buried lines. Metallic lines must be buried at least six inches below the soil’s surface. They can also be installed four inches below a four-inch concrete slab.

The conduits must be buried a minimum of one foot beneath the surface of your driveway or public road and a minimum of 24 inches beneath the surface of an alley or public street. Place them 2 inches below the rock’s surface, then cover them with concrete.

Bury Electrical Conduit: Things to Consider

Direct Cable Burial

The UF cable (subway feeder cable) is fundamentally designed and manufactured with features that make it perfect for burial.

This cable must be buried at a depth of 24 inches. The cable is less likely to be cut or disturbed by routine excavation if it is so far subway.

However, some municipalities and states/provinces require that local utilities be contacted so that they can mark where the subway utilities are on their property.

When purchasing a UF cable, you should take particular care to differentiate it from ordinary NM (non-metallic or Romex) cable. In most cases, the UF cable has information printed on the jacket that identifies it as UF.

(Video) Pulling Long Cable Through Underground Conduit

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Use of UF cable on the ground

Although the UF cable is intended to be buried, it can also be used on the ground.

Among other things, if you have a length of cable that is moderately buried and moderately above ground, and you choose not to splice the burial cable with a length of cable above ground, you can use a UF cable for the finished length of the cable.

However, keep in mind that any UF cable used in above-ground apps must pass through a conduit where it can be damaged.

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Coated electrical cable in PVC conduit

Currently, the National Electrical Code (NEC) tells us that the required burial depth of electrical cables in various rigid non-metallic conduits, such as PVC, is 18 inches.

To schedule 40 PVC burial depth, you should follow our advice.

The cable in any conduit, with the addition of PVC that is buried in this depth, is not at risk of being cut or disturbed by regular excavation.

However, keep in mind that no cable or conduit is protected against excavation by innovative equipment such as trenchers or backhoes.

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Outstanding measures for low-capacity cables

Suppose your cables are operating on a 120-volt circuit, protected by a 20 amp or less circuit breaker, and have a ground fault circuit interrupter to secure the subway segment of the cable. In that case, you can reduce the burial depth of your cables.

The generally applicable depth is 12 inches, or you can reduce it to 6 inches if you secure the cables with 2 inches of accuracy. Below an entry path, it is feasible to require only 12 inches of burial depth.

Conduits require for installation in 2 inches of solid rock with accuracy. These depth reductions apply no matter which burial procedure is chosen.

Direct Burial of Cables or Conductors

Subway nutrition cables, labeled as UF, have the possibility of being buried without added custody of the ducts because they have a strong cover created for burial.

Bury UF cables 24 inches below the ground area and 18 inches deep at the time they protect by 2 inches of precision.

For all other apps, the burial depth is the same as that detail for conduits. Except for that conduits require UF cables in 2 inches of solid rock.

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Reduced depths for control cables

Control circuits carrying less than 30 volts are essentially less dangerous than those carrying higher voltages and therefore have the potential to be buried less intensely.

The required recurring depth is 6 inches. For all other apps, the same depths apply to buried UF cables, except that control cables must be buried at 18 inches below the driveways.

(Video) HOW TO BURY CABLES WITH CONDUIT WITHOUT RUINING GRASS - in less then 30 minutes

Wires and Cables for Underground Lines

There are a variety of ways in which electrical wiring can be arranged underground. The procedure you use may depend on what allow or suggest by local Code authorities. So always check with your local building inspection office to find out what indicate on your social network. Generally, however, the National Electrical Code provides three ways to operate subway circuits:

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UF (Underground Feeder) cable laying directly on the ground

This knows as direct burial, and if you do this, the UF cable should be at least 24 inches below the ground area. to reduce the chance of the cable being punctured by a regular shovel. Besides, the vertical sections where the cable descends to the ground on the dwelling side and emerges from the ground on the unit side must be housed in a rigid conduit. At the bottom of the trench, a sweeping attachment attach. At the ends of the vertical duct and the cable snake through the elbows and rises into the duct on both sides.

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Pass the cable through rigid galvanized metal conduit

In this procedure, the duct can have a depth of up to 6 inches, and the particular conducting cables inside have to have a “W” label to indicate that they are waterproof. The THWN-2 cable, among other things, is a level type for passing through subway ducts. Use a thick-walled conduit of at least 3/4 inch diameter for this application. Never use a thin-walled EMT conduit for subway apps.

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Run the cable through Schedule 40 PVC conduit

Here, the conduit must be at least 18 inches deep, and, again, the particular conductor wires within the conduit must have a “W” waterproofing arrangement, such as THWN-2.

An underground electrical wire is the best option

Running UF cable through metal or PVC conduit.

Although not frequently done, it is easy to run UF (but NOT NM) cables through metal or PVC conduit in a subway application. However, it can be complicated to locate the cable through the conduit unless the conduit is at least 3/4 inch in diameter. Most electricians choose to fish particular waterproof THWN conductors through conduit simply because it is simpler.

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Frequently Asked Questions

What is the minimum burial depth for the PVC duct?

18 inches

The National Electrical Code (NEC) establishes the elemental depth of burial of electrical cables in rigid. Also non-metallic conduit, in the same manner as PVC, at 18 inches. The cable is in a conduit, with the addition of PVC that bury in this depth. It does not run the risk of cutting or being disturbed by regular digging.

Can you bury the cable without the conduit?

If you only need a source of nutrition (no wires to monitor lights from inside the house). You can use a direct burial wire, placed in the ground without a conduit. Popular as UF for “subway feeder”, the cable has a heavier plastic jacket than the Romex used inside the home.

Is it essential to bond the subway electrical conduit?

No. Anyone who says not to glue down the electrical conduit has NO initiative in what they are talking about. You don’t require priming, but it is entirely essential to glue it. Yes, it estimates that water will enter, but for that reason. We need the use of moisture-managed conductors and wires.

Final Words

The issue of installing electricity in our place of life is difficult; however, if you follow our steps and advice, you will be able to do this correctly. It is best to leave this to the experts in the field.

The electrical wire underground is not just any topic; it is necessary to know enough about it to avoid having inconveniences.

It is crucial to keep in mind that the direct bury wire is one of the most notorious steps.

The underground electrical wiring is essential for each of the houses; it gives you electrical functionality throughout your home, giving you satisfaction and security.

However, if you have already read our article, you are ready to extend the cable to your home. And parking lot and fill in the connections.

(Video) Bury 100ft of wire 10in deep in 10 minutes without any mess.

Make sure that all cables contain within the conduit. As they pass through the walls of the house and parking lot to the interior. After plugging in the plugs and lights in the parking lot. The last step will be to plug the circuit breakers into the primary service panel.

FAQs

How deep should electric cables be underground? ›

Underground electricity cables are usually buried between 0.45m and 1m below the surface of the ground, in ducts, or may have a layer of tiles, boards or coloured plastic tape placed approximately 150mm above them.

How deep do you put conduit in the ground? ›

Additionally, different types of wire and conduit have specific depth requirements:
  1. GFCI-Protected Underground Feeder Cable - 12 inches.
  2. Underground Feeder Cable (UF Cable) - 24 inches.
  3. Electrical Wire in Rigid Metal Conduit - 6 inches.
  4. Electrical Wire in PVC Conduit - 18 inches.

How deep does 240v cable need to be buried? ›

Most of the rules involve protection of the wiring from damage. The NEC (National Electrical Code) requires that UF cable be placed in a trench at least 24 inches deep. In most communities, you will have to leave the trench open until the inspector arrives to approve the depth.

What is the minimum depth for cable laying below ground? ›

The minimum depth for cable laying below the ground varies according to the voltage capacity of the cable. The depth should be atleast 0.9m for 3.3kV to 11kV cables, 1.05m for 22kV to 33kV cables. The minimum depth of a low voltage cable should be 0.75m.

What is code for underground conduit? ›

NATIONAL ELECTRICAL CODE

NEC 300-5 Conductors emerging from underground shall be installed in rigid metal conduit, intermediate metal conduit, or Schedule 80 rigid nonmetallic conduit to provide protection from physical damage.

What size conduit should I use for underground electrical? ›

In general, underground primary distribution will require 2 ½ inch schedule 40 PVC conduit. The conduit will be installed 42 inches below final grade. Single phase lines will require one conduit while three phase lines will require three conduits.

How deep do you bury PVC electrical conduit? ›

In the United States, the National Electrical Code specifies that direct burial cable (i.e., type UF) must be buried at least 24 inches deep. If you put the wire in PVC conduit, then the minimum depth is 18 inches.

What is code for burying electrical cable? ›

NATIONAL ELECTRICAL CODE

NEC 300-5 Generally, cables approved for direct burial shall have a minimum cover of 24 inches. When wiring is installed at dwellings in approved non-metallic raceways, the minimum cover can be reduced to 18 inches.

How deep should utilities be buried UK? ›

Although underground gas pipes should be buried at least 375mm, and electrical cables 500mm into the ground, they're often not that deep. So, regardless of the depth of any excavation, you must take steps to avoid them. The best option is to use a service detection device.

How deep should Armoured cable be buried UK? ›

A minimum installation depth of 450mm underground is typically recommended for best practice. This increases to 600mm in locations where there is a higher possibility for potential disturbance.

How deep do you bury PVC electrical conduit? ›

In the United States, the National Electrical Code specifies that direct burial cable (i.e., type UF) must be buried at least 24 inches deep. If you put the wire in PVC conduit, then the minimum depth is 18 inches.

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