Once the academic house construction has been initiated, the contractors and architects will walk you through the house’s plumbing, electrical, heating, and cooling traits and comprehensively clarify these fixtures. During the outlining stage, the installations are fitted before the ceilings and walls are fixed permanently with the help of drywall. These fixtures are then supposed to be assessed and vetted by the initial inspector to avoid removal after inspection. Plumbing fixtures and pipes are, however, installed before the electrical components. For the plumbing phase, the setting of the water supply, drain pipes, and sewage pipes are mounted at the holes drilled by the inspectors and contractors inside the framing structure of the house, which is the backbone of the building.
One thing to note is that plumbing and electric supply can be drilled and installed simultaneously. However, most professional suppliers prefer laying the plumbing pipes before starting the electrical components. This is considered safer, convenient, and much more accessible, as electric wiring and features can be drafted around the pipes and other plumbing details.
What is a conduit?
A conduit represents an engineering pipe or tunnel through which water, electrical wires, or other designated items can pass. An electrical conduit is a metal or plastic tube that protects and routes electrical wiring in a building or structure.
How deep is it to bury an electrical conduit?
Usually, if you build a house or any residential property, you must bury an electric conduit at least 6 inches below the soil surface. However, you can bury them at 4 inches under a 4-inch concrete slab.
In civil engineering, you bury an electric conduit under the driveway. The conduits must be below a depth of 18 inches, while if you bury an electric conduit below the public road, you will need at least 24 inches in depth.
How deep are power lines buried?
According to the National Electrical Code, power lines must be buried at least 24 inches deep because all higher-voltage circuits must be buried deeper than 24 inches.
Electrical wiring
The electrical installation that includes cabling, wiring, and presence of switches, knobs, power outlets, boats, sockets other lighting fixtures are deeply embedded within the structure.
Typically, home wiring includes electrical wiring, particularly lighting, and an equal distribution of power throughout the building. These are carefully and permanently set up through which portable devices such as telephones, heating and ventilation systems, home theaters, and computer networks are controlled and monitored. Regarding the safety regulations, these safety and preventative measures for wiring installation vary worldwide. Considering your local admissible laws, homeowners sometimes have the authority to install wiring in homes, whereas licensed electricians perform most.
The initial phase of electrical wiring begins before the construction of the walls is finished. This dodged additional effort and welcomed the electrical wiring of other equipment, such as the security or home theater systems. Therefore, a proper plan and schedule are necessary for an electrical application in multi-story buildings, condos, and apartments.
Commonly, the following electrical fixtures are required.
- Wall outlets as PowerPoint
- Light knobs, switches, and fixtures
- Telephone and Internet
Those mentioned above are usually found in any construction. Still, unique and high-end aspects are occasionally seen, including security systems, CCTV cameras, solar energy management, home theater systems, Internet audio systems, and automation.
What kind of electrical wire can be buried underground?
Electrical wires such as USE-2, Aluminum URD Direct Burial, UF-B Underground Feeder Cable, and Tracer Wire can be buried underground.
Can a UF cable be installed in the conduit?
UF cable can be installed in a metal or PVC conduit for the ground. However, NM cable or non-metallic cable, as a flexible electrical cable, can not be buried in any wet environment, and especially can not be buried underground.
Can I use Romex in conduit?
Yes, you can use Romex in conduit. Romex, NM cable, or non-metallic cable, is a flexible electrical cable that can not be buried in any wet environment, so you should run your Romex wiring in conduits.
Underground cable system
The underground cable system is used for inaccessible and hard-to-find places where power outlets and design needs to be applied. These places are challenging, tricky, and impractical and can also cause danger if overhead lines are used. The applications of underground cables are standard for high-rise buildings, urban areas, factories, and even unique accommodations to provide power supply starting from the overhead posts towards the consumer location. The advantages of installing an underground cable system are several and as follows:
They function on a smaller voltage fraction
They are less faulty
Less maintenance
Despite providing a multitude of benefits, they are slightly expensive to implement as their cost may vary depending on the level of construction and available voltage.
Types of underground cables by voltage
Buried conduits are categorized by voltage capacity or by the construction process.
- Underground cables are classified by voltage and have the following characteristics:
- Low tension cables: These have a maximum voltage capacity of 1000 V (1 kV)
- High tension cables: These can bear a maximum voltage of 11 kV capacity
- Super tension cables: These can manage 33 kV of electrical capacity
- Extra high tension cables have a maximum voltage ranging capacity of 66 kV.
- Excellent voltage cables are used for professional or residential scenarios above 132 kV.
Types of underground cables by construction
Belted cables: This has an extra layer of oil-infused paper wrapped around the insulated conductors. This setting is ideal and practical for low and medium voltage levels up to 11 kV.
Screened cables are applied with specialized construction and divided into H-type and S.L-type cables.
When the voltage requirement range is 66kV, pressure cables are used, and solid cable materials are impractical. Cables can use pressurized gas or pressurized oil.
Electric power needs to be provided to a garage, garden area, or even an inaccessible location on the premises, which requires conduit material specially manufactured to accommodate the electric current, the exact depth and height of the trench, and the exterior fabric of the electrical fire.
Tools required:
- Four-in-one screwdriver
- Flexible wrench
- Corded drill
- Spade
Materials required:
To move ahead with underground cables, the following materials are required:
- Electric wire with waterproof characteristics
- Conduit and fittings of either metal or plastic
- Service entrance ell (wire)
How to install an underground conduit?
You have four options if you have decided to place an electrical line deep underground within your premises. The preference depends on the exact amount of voltage and power intensity and the type of soil in the backyard. If the ground is easily accessible and the deck requires less effort, quickly digging it deep can save tons of money. For this purpose, you would not need a metal conduit. However, if the sand is hard to break, out-of-the-way, and has rocky information, keep the digging to a minimum. Regardless of the type of reference, you need to place a service entrance equipped with a temporary cover, providing complete access to the wires placed above the ground level. Finally, before starting the process, you must be acquainted with the local codes provided and screened by the inspector for a permit.
Electrical cable digging
An initial assessment of the exact depth of digging is required. This will eventually determine the type of electric cable positioned underground. For example, suppose the intention is to put an underground cable solely for the transference of electrical power of voltage to an inaccessible location. In that case, the underground wires can be installed and placed at different depths depending on the category of conduit.
If the digging is about 6 inches deep, install a galvanized electrical conduit with a metal exterior and individual conductors inside the wires. For a whole 12-inch deep trench, you can directly install GFCI-protected underground cables with a short infused PVC length.
For an 18-inch-deep trench, install THWN-2 conductors in a prolonged length of PVC conduit, as this will protect the cables. At the deepest, 24 inches, you can locate and install the underground feeder cable with the help of a PVC conduit going 18 inches underground.
Deep trenches (6, 12, 18, 24 inches):
To bury 6 inches deep, the galvanized metal solid conduit is used with individual conductors. To identify waterproof conductors, look for the W sign on the profile. Any size circuit can be accommodated for a trench as deep as 6 inches. However, the cost is slightly more.
For 12 inches, lay an underground feeder cable if it completes the following checklist:
1. GFCI protected before placement
2. Has 120 volts
3. Protected by a 20 amp fuse or breaker.
THWN2 conductors are placed within the PVC conduit for 18 inches. This solution is ideal even for electricity accessibility other than water-related mechanisms.
UF-B wire cable is 24 inches long. However, the conduit should be exposed to the outside of the house and 18 inches. Extensive digging is required, which is easier if the soil is soft and easily excavated.
Primary uses of conduits
Conduits are predominantly utilized for safety purposes. They mitigate the risk of unforeseen electrical incidents, including short-circuit, electrocution, and fire. Maintenance of conduit is practicable and accessible as wires are grouped, typically isolating them from other cables. Choosing the suitable conduit for your underground cables is essential because multiple options and preferences are available. Some of the conduits are old-fashioned, but there has been substantial development in the type and range of conduits open.
Metal conduits are available in different materials and have a wide range of budgets and types of construction. PVC conduit, rigid metal conduit, metallic electrical tubing, and flexible metal conduit are well-known and durable categories of tubes. Some are made of stainless steel, which has resilient features and is lightweight. However, the traditional conduits cannot perform under extremely low temperatures, particularly below -5°C. They are also known to disseminate poisonous fumes.
Another conduit material type is fiberglass for those looking for a more innovative feature than traditional ones. Fiberglass has unique characteristics and is irrepressible and durable. It is highly novel compared to traditional ones, and its versatility makes it easily applicable to indoor and outdoor house projects. The protection and prevention level offered by fiberglass is higher than steel and aluminum. Their installation is quite reasonable on the budget, and their economic property makes it preferable.
There are multiple advantages to placing a fiberglass conduit. First, it has a low coefficient of friction, which lets the cables move without the presence of friction. Fiberglass is also highly resistant to corrosion, moisture, UV rays, and other chemicals. Furthermore, it is non-conductive and featherweight, and the installation dates are also low on budget.
From 2022 onwards, Mark has also been contributing author of home repair articles at nimblefreelancer.com.
Read more on Mark Brown's biography page.
Contact Mark: mark@nimblefreelancer.com