Rigid Metal Conduit (RMC):
RMC is composed of heavyweight galvanized steel and installed with threaded fittings. Known for being very strong, RMC is unfortunately one of the more expensive electrical conduits when it comes to both materials and labor. Aluminum is another material used for RMC, and may have additional coating applied to better resist corrosion.
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Galvanized Rigid Steel (GRC):
Approved for indoor and outdoor applications, GRC is made from steel and is traditionally found in industrial and commercial applications, GRC has been a long-time industry standard and benefits from impressive impact resistance, as well as UV-stability and the ability to protect from EMI (electromagnetic interference). Unfortunately, its heavy weight and poor field handling make GRC particularly expensive to install and it can be highly susceptible to corrosion. GRC's conductivity makes it susceptible to fault conditions in which the conduit and wire may weld together.
Intermediate Metal Conduit (IMC):
Approved for the same applications as RMC, IMC is a steel conduit that is slightly lighter than RMC and rated for outdoor use. It can be more cost-effective than RMC, available threaded or unthreaded, and may or may not be coated. Compared to GRC and RMC, IMC has much thinner walls that can handle more wire fill but is more susceptible to kink. IMC only goes up to 4 inches in trade sizes, so it is significantly smaller than other conduits.
Electrical Metallic Tubing (EMT):
Thin-walled and unthreaded, EMT is typically made of coated steel and used in place of GRC in commercial and industrial applications, though it is commonly found in residential applications as well. It can also be made of aluminum and is approved for use in concrete but is not permitted to be installed where subject to physical damage. EMT is not able to offer the same level of protection as GRC. It is easily bent but can not be field threaded because of its thinness. Common trade sizes run from .5 inch to 1.5 inches.
Rigid Nonmetallic Conduit (RNC):
Non-metallic, unthreaded, smooth-walled tubing is available in multiple substrates including high-density polyethylene, PVC, and RTRC (fiberglass). The capabilities and specs vary by substrate but several forms of RNC are approved for underground or direct burial use.
RTRC Conduit:
Available in various wall thicknesses and threaded, RTRC (reinforced thermosetting resin conduit), or fiberglass conduit is created by tension-winding strands of fiberglass over a rotating mandrel, before impregnating the strands with resin and curing under high temperature, resulting in high flexural strength and high-temperature resistance. RTRC features the broadest range of corrosion resistance of all in-market conduit materials, as well as low burn-through, UV stability, superior temperature range (including excellent handling in low temperatures), and the ability to retain its original shape after impact. Its support distances are comparable with GRC, PVC-coated steel, and aluminum electrical conduit.
RTRC is significantly lighter in weight than traditional conduit materials, resulting in the lowest labor installation rates for most diameters per the National Electrical Contractors Association (NECA) Manual of Labor Units. In terms of raw material costs, it is one of the more affordable electrical conduit options. Phenolic RTRC meets NFPA 130 requirements and is suitable for speciality applications requiring low smoke, no flame, zero halogen, 2-hour fire-rated conduit for use in Class I Div 2 areas.
PVC Conduit:
Available in varying wall thicknesses and threaded, PVC is light and commonly used for applications requiring non-metal electrical conduit. PVC conduit is not recommended for use in direct sunlight due to poor UV stability. It is relatively easy to heat and field bend with the use of a hotbox conduit bender, but must be mounted to allow for expansion and contraction due to a high coefficient of thermal expansion, and may deform after installation in environments that are too hot. Traditionally PVC has been an inexpensive conduit, however, in recent years it has become more expensive and harder to source, due to ongoing supply chain issues. In these cases, American-made RTRC is often substituted.
Electrical Nonmetallic Tubing (ENT):
Thin-walled and corrugated, ENT (electrical nonmetallic tubing) is flame retardant but not fire rated. It is not approved for use in exposed locations but is commonly used inside walls or within concrete blocks. Known for its extreme flexibility ENT can be field bent by hand without requiring any special tools or the application of heat. ENT is available in PVC in trade sizes up to 2 inches. Its support spacing is limited to 3 feet and within 3 feet of terminations.
National Electrical Code (NEC) guidelines, local codes, and engineering specifications most often dictate which conduit to consider for use in a project. Although size and type are key aspects, there are many characteristics to consider when choosing an electrical conduit, including:
The correct conduit should:
ENT conduit is a flexible, corrugated plastic conduit that is easy to handle and install. It is commonly used in both indoor and outdoor applications where flexibility is required as it can bend by hand on field without requiring any special tools, and provides good protection against moisture. ENT conduit is often utilized in residential wiring, including installations behind walls and in concrete slabs.
Flexible and easy to bend.
Corrugated exterior for added strength.
Smooth interior for effortless wire pulling.
Flame-retardant properties for enhanced safety.
Lightweight and easy to handle.
Resistant to moisture and corrosion.
Suitable for both indoor and outdoor applications.
Ideal for concealed and exposed installations.
Compatible with a wide range of electrical boxes and fittings.
Lower impact resistance compared to rigid conduits.
May require additional support in horizontal installations.
Limited temperature range compared to some other conduit types.
LFNC is a type of conduit that is designed to be waterproof and dustproof. It features a liquidtight outer jacket that provides resistance to moisture, oils, and other non-hazardous liquids. LFNC is frequently employed in outdoor and wet locations where protection against moisture exposure or liquid ingress is necessary.
Flexible and easy to bend.
Resistant to moisture, oil, and chemicals.
Suitable for wet locations.
Provides strain relief for wires.
Ideal for outdoor and underground applications.
Resistant to corrosion and rust.
Easy to install and modify.
Can be used in areas with exposure to chemicals.
Suitable for use with liquid-tight fittings.
High-Density Polyethylene (HDPE) conduit is a durable and versatile option for electrical wiring installations. HDPE conduit is made from high-density polyethylene, a thermoplastic known for its excellent strength, impact resistance, and chemical resistance.
High strength and impact resistance.
Lightweight and flexible.
Resistant to chemicals, moisture, and UV radiation.
Excellent long-term performance.
Suitable for both aboveground and underground installations.
Can be used in various environmental conditions.
Resistant to corrosion and abrasion.
Can withstand a wide range of temperatures.
Ideal for outdoor and industrial applications.
Requires specialized tools for cutting and joining.
Higher cost compared to some other conduit types.
Less rigid than PVC or metal conduits.
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Mechanical Strength: Plastic conduits have lower mechanical strength compared to their metal counterparts. They may not provide as much physical protection to wiring, especially in areas prone to impact or mechanical stress.
Temperature Limitations: Plastic conduits have temperature limitations and may not be suitable for high-temperature environments or applications where fire-resistance is required.
UV Resistance: Some types of plastic conduits may degrade over time when exposed to UV radiation, so they may require additional UV protection if used outdoors.
Expansion and Contraction: Plastic conduits can expand and contract with temperature changes, which may require appropriate allowances during installation.
Cost: Metal conduits, especially rigid options, tend to be more expensive than plastic conduits.
Installation Complexity: Metal conduits may require specialized tools, such as conduit benders and threaders, for cutting, bending, and installation. They may also require more labor-intensive installation compared to plastic conduits.
Corrosion: While metal conduits are generally coated or galvanized to resist corrosion, they can still be susceptible to rust and degradation over time, especially in corrosive environments. Proper corrosion protection measures should be considered.
Weight: Metal conduits are heavier than plastic conduits, which can make handling and installation more challenging, particularly in overhead or long-run applications.
Conduit is an essential component in electrical installations, providing protection, organization, and safety for electrical wiring. It consists of pipes, tubes, or channels that enclose and shield electrical conductors, ensuring they are safeguarded from physical damage, moisture, chemicals, and other external factors. Here's why and when conduit is necessary:
Protection: Conduit serves as a protective barrier for electrical wiring, shielding it from accidental damage, impact, and exposure to harsh environments. It helps prevent risks such as short circuits, electrical fires, and electrocution.
Organization: Conduit allows for neat and organized routing of electrical cables, facilitating easier identification, maintenance, and future modifications or upgrades.
Safety: By enclosing electrical conductors, conduit reduces the risk of accidental contact, especially in areas where wiring is exposed or accessible to people or equipment.
Compliance: Conduit installation is often required by local electrical codes and regulations to meet safety standards and ensure proper installation practices.
Flexibility: Conduit provides flexibility in terms of future expansion or changes to the electrical system. It allows for the addition or removal of wires without the need for extensive rework or disruption.
Commercial and Industrial Buildings: Local codes typically mandate conduit usage in commercial and industrial buildings to meet safety requirements and facilitate easy maintenance and modifications.
Outdoor Installations: When electrical wiring is exposed to outdoor elements, conduit is often required to protect it from moisture, UV radiation, temperature variations, and physical damage. This includes applications like outdoor lighting, irrigation systems, or underground conduit runs.
Hazardous Locations: Conduit is necessary in hazardous locations where flammable gases, vapors, or combustible dusts are present. It helps contain any potential sparks or electrical faults, reducing the risk of ignition and explosions.
Areas Prone to Mechanical Stress: Conduit is necessary in areas where there is a high likelihood of mechanical stress, such as construction sites, industrial facilities, or areas with heavy machinery. It provides added protection against accidental impacts, vibrations, or crushing.
Public Spaces: In public spaces like schools, hospitals, or government buildings, conduit is often required to enhance electrical safety, prevent tampering, and facilitate efficient maintenance.
Selecting the appropriate conduit for your electrical installation is essential for ensuring safety, compliance, and functionality. Here's a guide on how to choose the right conduit, taking into account various factors:
Evaluate the material options available for conduits, such as PVC, metal (e.g., steel or aluminum), or flexible conduit (e.g., liquid-tight or corrugated). Consider the specific properties of each material, such as durability, corrosion resistance, and suitability for the intended application.
Evaluate the environmental conditions where the conduit will be installed, such as exposure to moisture, chemicals, extreme temperatures, or mechanical stress.
Choose a conduit material that can withstand these conditions. For example, PVC conduits are resistant to moisture and corrosion, while metallic conduits offer better protection against mechanical stress.
Determine the required mechanical strength based on the application. Consider factors such as impact resistance, load-bearing capacity, resistance to pressure and ability to withstand vibrations or external forces.
Consider the specific location of the conduit installation, whether it is indoors, outdoors, underground, or exposed.
Different locations may require different types of conduit. For outdoor or underground installations, you may need conduits with higher durability and weather resistance.
Assess whether the conduit will be exposed to chemicals or corrosive substances. Choose a conduit material that offers suitable resistance to these substances to ensure long-term performance and safety.
Look for conduits that meet industry standards and certifications relevant to your application. Examples include UL (Underwriters Laboratories) certifications for electrical safety in the US or CSA certifications for conduits in Canada, and AS/NZS certifications in Australia. Understanding your local codes and regulations for electrical conduit, and choose those suppliers who obtained the product certicates already.
Consider the need for flexibility in your electrical system. Will you need to make future modifications, additions, or upgrades?
Flexible conduit options, such as liquid-tight flexible metal conduits or flexible non-metallic conduits, provide easier access and allow for changes without extensive rework.
Determine the appropriate size and dimensions of the conduit based on the number and size of cables or wires that will be housed within it. Ensure that the selected conduit can accommodate the required capacity.
Research reputable brands that offer high-quality conduits and have a track record of reliability.
Consider factors such as the brand's reputation, customer reviews, and the availability of their products in your area.
Evaluate the cost-effectiveness and availability of conduit options.
Compare the costs of different conduit materials, considering both the upfront cost and long-term maintenance requirements.
Ensure that the chosen conduit is readily available in your area to avoid delays in the installation process.
Remember to consult with electrical professionals, such as electricians or engineers, for specific recommendations based on your project requirements. They can provide valuable insights and ensure compliance with local regulations.
Here are some projects that Ledes has participated in and the conduit types we provided for these projects.
The Champlain Hudson Power Express® (CHPE) is an innovative renewable power transmission project that aims to deliver clean and reliable energy to New York. This high-voltage direct current (HVDC) underwater and underground power cable project will connect the Quebec area to the neighborhood of Astoria in Queens, New York City.
The CHPE project plays a significant role in the state's energy transformation by reducing greenhouse gas emissions and contributing to a cleaner environment. It is designed to lower reliance on fossil fuels and promote the adoption of renewable energy sources. By delivering low-cost renewable energy to New York, the project not only helps meet the state's energy demands but also contributes to economic growth and job creation.
The CHPE project has selected Ledes' Schedule 40 rigid PVC conduit as the conduit of choice for its electrical installation. Ledes' Schedule 40 rigid PVC conduit is a durable and reliable option that provides excellent protection for electrical wiring. PVC conduits are resistant to moisture, corrosion, and various environmental factors, making them suitable for both indoor and outdoor applications. The selection of Ledes' Schedule 40 rigid PVC conduit ensures the safety and longevity of the electrical infrastructure associated with the CHPE project.
Al Dhafrah PV2 Solar Power Project and 2.6 GW PV project in Saudi Arabia are the two biggest solar projects in the world. They are significant contributor to the country's renewable energy goals and committed to transitioning towards sustainable energy sources. These two projects involve the development and and implementation of a large-scale power generation capacity of 2GW and 2.6 gigawatts (GW) using renewable energy sources.
In line with the project's requirements, Ledes' solar series corrugated conduits have been chosen as the conduit solution. Ledes' solar series conduits offer reliable protection for the electrical infrastructure associated with solar and wind power projects. They are designed to withstand the demanding environmental conditions found in renewable energy installations, ensuring the safety and longevity of the electrical wiring and cabling.
The Melbourne Metro Rail project is one of the largest and most complex infrastructure projects in Australia. The Metro Tunnel includes the construction of twin 9- kilometre rail tunnels with five new underground stations. This underground project includes the installation of high capacity signalling and operation electricity, which has strict requirements for electrical and fire safety.
To meet the electrical safaty requirements, it choosed Ledes' Low Smoke Halogen Free conduit and fittings for its electrical wiring system. Ledes' low smoke halogen free conduits are insulated and provide better prevention against electrical shock accidents. They have excellent fire resistant performance, certified with V0 rating fire resistance. And it does not produce dense smoke and toxic fume during the fire event. Provide additional protection for the electrical system and personnel.
In conclusion, selecting the right electrical conduit is crucial for ensuring the safety and efficiency of wiring system. You need to understand the different types of electrical conduit available and specific project requirements. And consider from these factors we've talked in the article and together with your own specific needs to decide which conduit type to choose. Remember to prioritize safety, durability, and compliance with local regulations.
If you're not sure which type of electrical conduit to choose for your application, LEDES' professional team can help provide the best electrical solution for you.
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