What You Need to Know Before Buying Electrical Conduit

Jul. 15, 2024

What You Need to Know Before Buying Electrical Conduit

At ANAMET Electrical, Inc., we supply flexible electrical conduit to customers in various markets. As these components are designed to connect and protect electrical wiring, cables and other equipment, they play a critical role in many electrical and electronic applications. That&#;s why it is important to choose carefully when you need electrical conduit for your project.

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This guide will explain what you need to know before buying conduit for your application. It provides an overview of what electrical conduit is, what types are available and what to consider before installing conduit.

What is Electrical Conduit?

When electric lights were new to the world, existing pipes for gas light were used to route wiring to new electric light bulbs on existing light fixtures. The beginning National Fire Protection Association () and National Electrical Code () preserved the idea of using pipe or tubing to protect electrified wiring. Electrical conduit is now tubing that electricians install to protect and route electrical wiring. It can be made from a variety of rigid or flexible materials, such as metal, PVC or thermosetting resin, depending on its intended use. Electrical conduit can be found in attics, basements, crawl spaces and on various interior and exterior spaces and surfaces.

What Types of Electrical Conduit Are Available?

The National Electrical Code (NEC) defines the types of approved electrical conduit. This publication is frequently revised to keep up with innovative technology. States and municipalities decide how this Safety Code is applied or enforced. The requirements for electrical conduit are finely detailed. Electrical conduit can be rigid (metal, PVC or thermosetting resin) or flexible (metal (FMC), liquid tight metal (LFMC) and liquid tight non-metallic (LFNC). All conduit comes in a variety of sizes and there are limitations on how each type may be used.

Rigid metal conduit
is the heaviest and thickest conduit material option. It offers protection against mice and rats in basements, garages and similar environments. Due to its durability, it is commonly used in areas with extreme or harsh conditions. It is typically made from steel or aluminum, the latter of which is recommended for high-moisture environments since it resists corrosion. If the conduit must be installed around a corner, you may need a conduit bender, conduit couplings, offset fittings, and/or elbows.
Rigid PVC and thermosetting resin conduit
are the lightest conduit material and the least expensive conduit option. It is used to protect electrical wiring from moisture and dirt. It is corrosion resistant, moisture resistant and non-conductive. It is used outdoors and below ground. It is commonly used for lawn irrigation controls and swimming pools.
Flexible metal conduit (FMC)
is called Greenfield or Flex in the building trades. It is recommended for dry locations indoors because it is not liquid tight. Its flexibility and lighter weight make it easier to install than rigid conduit. It is frequently used in the interior walls of houses and office buildings, cubicles and office ceilings (for connecting power to light fixtures).
Liquid tight, flexible, metallic conduit (LFMC)
is typically covered with a waterproof plastic coating to keep out moisture. Its flexibility enables it to be used in places with tight bends where rigid conduit would be hard to install. Typical uses include bridges, ground burial, paper mills, petrochemical facilities and water treatment plants.
Liquid tight, flexible, non-metallic conduit (LFNC)
is suitable for use in dry, wet, or oily locations. It can be used in indoor or outdoor environments for industrial and commercial applications. Typical uses include ground burial, HVAC units, pools and spas.

What Should I Consider Before Installing Electrical Conduits?

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You will need to purchase conduit connectors (fittings) to install a conduit system. Fittings allow conduit to be connected to an electrical junction box.

If you are buying conduit fittings from a supplier for the first time, you should keep in mind the following considerations to make sure you are getting the best solution for your needs:

What are your local Safety Code requirements?
Although the National Electrical Code describes conduit installation for operating conditions, local inspectors may provide guidance that can save money and time on installation, inspection and approval for wiring and conduit installation.
Are the fittings the right size?
The diameter of the fitting must match the diameter of the selected conduit to provide a secure and liquid tight connection.
How long does the conduit and fittings need to last?
If the conduit only needs to be used until the next remodeling project, you may shop for less durable, lower cost conduit and fitting options.
Are the conduit and fittings made of material appropriate for the installation conditions?
Conduit is made of a variety of materials, both metal and non-metal, for resistance to intrusion, corrosion and liquids. Fittings should be equally durable. For liquid tight conduit, choose liquid tight fittings with seals and rings.
Does the supplier offer the type of fittings I need?
The supplier you choose should offer the fittings matching the conduit you need for your project.
Will the supplier deliver the fittings by the time I need them?
The supplier should be able to deliver the connectors to you with the conduit you purchase.

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Can the supplier provide a customized solution?
If your project has distinctive features, you should look for a supplier that can provide conduit and fittings so you can be sure of safe and secure electrical connection to your specifications and standards.

Why Partner With ANAMET Electrical for Your Electrical Conduit Needs?

Operation of electrical equipment is dependent on safe, reliable and secure electrical connection. Electrical conduit protects electrical connections, which is why understanding what electrical conduit is, what types are available and what to consider before installing conduit is vital.

Looking for high-quality flexible electrical conduit and fittings? ANAMET Electrical has got you covered! We are an industry-leading provider of flexible electrical conduit and fittings. To learn more about our product offerings, check out our product catalog or contact us today. For specific product questions or pricing details, request a quote.

Selecting the Right Type of Electrical Raceway

Our previous article covered the main types of metallic conduit for electrical conductors, and now we will discuss nonmetallic conduit and its applications. Nonmetallic conduit is normally the more affordable option, providing improved electrical isolation and corrosion resistance, while reducing the degree of physical protection. The approved uses of metallic and nonmetallic raceway overlap in various applications, so there are many cases where design engineers must make a choice.

The most common types of nonmetallic conduit are the following:

Abbreviation

Full Name

PVC
HDPE
RTRC
LFNC
ENT

Rigid Polyvinyl Chloride Conduit
High Density Polyethylene Conduit
Reinforced Thermosetting Resin Conduit
Liquidtight Flexible Nonmetallic Conduit
Electrical Nonmetallic Tubing

Like with metallic conduit, all electrical installations must be according to the NFPA National Electric Code and the NYC Electrical Code. Conductors are not intended for unprotected installation, except for specific types that include metallic armor or polymer sheathing.

Keep in mind that this article is no replacement for electrical codes; the technical information provided here is very general. When working with engineering projects that involve electrical installations, you should check the specific code requirements for each application.

Rigid Polyvinyl Chloride Conduit (PVC)

PVC is possibly the most common type of nonmetallic conduit, being lightweight and affordable, while offering decent mechanical resistance for its low weight. In addition, it is virtually unaffected by humidity and corrosion, and is also an electrical insulator. However, the insulating properties of PVC are both a benefit and a disadvantage: the conduit itself cannot be electrified, but a grounding conductor becomes mandatory as a result, while metallic conduit can be used as both raceway and grounding in various applications.

PVC also offers features that simplify installation: it can be heated for quick manual bends, recovering its rigidity once it cools down. In addition, its low weight simplifies handling, and the conduit is easy to cut. PVC fittings are unthreaded and designed for slip-on installation, using solvent cements. PVC pull boxes also bring the reduced weight advantage, making them easier to handle and install.

This type of nonmetallic conduit is available with three different wall thicknesses: Schedule 20 is the thinnest, Schedule 40 is intermediate, and Schedule 80 is the thickest. Trade sizes range from ½&#; to 6&#;.

Schedule 20 PVC, with its thin walls, is not approved by the NEC for electrical installations. Therefore, it is used mostly in communication systems.
Schedule 40 PVC is the general-purpose option, adapting to a wide range of applications.
Schedule 80 PVC is used there conduit is exposed to physical damage. It is more expensive than Schedule 40, but its added strength increases the allowed applications.

The use of PVC conduit is not allowed in hazardous locations, areas where the ambient temperature exceeds 50°C (122°F), or applications where conductor insulation temperature exceeds the rated temperature of PVC. When used for lighting circuits, PVC cannot be used as physical support to hang lighting fixtures. Although the code does not prohibit its use with low ambient temperatures, consider that extreme cold can make PVC brittle, offering reduced protection for conductors.

High Density Polyethylene Conduit (HDPE)

HDPE is a type of nonmetallic conduit for applications where the circuit is buried or encased in concrete. It is not approved for indoor use or for exposed installation. Like PVC conduit, HDPE is not allowed in hazardous locations unless the code makes a direct exception, and it subject to the same ambient temperature and conductor insulation temperature limitations. The approved HDPE trade sizes range from ½&#; to 6&#;.

Reinforced Thermosetting Resin Conduit (RTRC)

RTRC is more commonly known as fiberglass conduit. Its applications are very similar to those of Schedule 40 PVC, but there is one key advantage: PVC can become brittle when exposed to very cold weather, while RTRC conserves its mechanical properties. RTRC is suitable for exposed or buried installation, indoor or outdoor use, and is unaffected by humidity and corrosion.

The applications where RTRC is not allowed are similar to those of Schedule 40 PVC: hazardous locations, luminaire support, and areas where it is exposed to physical damage or high temperature. Like with PVC and HDPE, trade sizes range from ½&#; to 6&#;.

Liquidtight Flexible Nonmetallic Conduit (LFNC)

LFNC has a self-explanatory name: it is a type of nonmetallic conduit intended for connections and cable runs with obstacles that are difficult to bypass with rigid conduit. LFNC is a versatile option, approved for various indoor and outdoor applications. Usage is not allowed where it will be exposed to damage, in hazardous locations, or if temperatures exceed conduit ratings. Like PVC, LFNC is vulnerable to extreme cold: it may become brittle, losing its flexibility.

Unless codes make an exception, LFNC should not be used in runs longer than 6 ft or with circuits above 600V. Approved trade sizes range from &#;&#; to 4&#;.

Electrical Nonmetallic Tubing (ENT)

ENT has similar applications to LFNC, but can be used for runs longer than 6 feet. In indoor locations, ENT can be either exposed or concealed. It resists moisture and corrosion, but can only be used outdoors if encased in concrete or protected from sunlight. Direct burial is not allowed, and it can only be installed exposed to the sun if specified as sunlight resistant.

ENT trade sizes range from ½&#; to 1&#;, and it is subject to the same usage restrictions that apply for many other types of nonmetallic conduit: hazardous locations, high temperatures and luminaire support.

Additional Recommendations

Although each application is unique, nonmetallic conduit generally offers a cost advantage over metallic conduit, giving up on some physical protection. However, keep in mind that metallic conduit may be mandatory in various applications; for example, the most demanding environments typically require rigid metal conduit (RMC) or intermediate metal conduit (IMC).

To achieve the best results in electrical installations, working with qualified professionals is highly recommended. In new constructions, you can achieve drastic cost reductions with smart design decisions. For example, energy efficiency reduces the electrical load, which in turn reduces conductor and conduit diameter.

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