Why are engineers switching to certain types of conduit?

Why are engineers switching to certain types of conduit?

Engineers focus on delivery of effective design solutions within a budget and schedule. While simple electrical jobs cost only a few hundred dollars, larger installations may be more expensive due to the specific demands, needs or harsh operating conditions where electrical supply must be sustained and protected.

National Electrical Code (NEC) changes and new products open opportunities for engineers to improve protection of electrical wiring. Here are conduit options engineers consider for protecting electrical wiring.

Understanding Electrical Conduit

Electrical conduit is critical for protecting electrical wiring at varying current and voltage levels in a variety of service conditions. Conduit may be rigid, flexible, metal, non-metallic or liquid tight.

Choosing the right conduit for operating conditions is crucial for successful completion of a project, passing inspection, turning over the project to an owner’s use and avoiding callbacks to repair faulty systems during and after the warranty period.

Engineering Considerations for Conduit

Rigid and flexible conduit types are available for protecting wiring. Each has attractive features and drawbacks. Below we’ll look at features that help engineers choose an electrical conduit to meet requirements.

Conduit may be rigid or flexible. Here are a few considerations affecting choice.

Rigid Conduit Options

Rigid conduit has a great reputation for use in the construction industry. Engineers choose this type of conduit if installation can be done and forgotten.

• Rigid metal (galvanized steel or stainless steel) conduit withstands harsh environments. The cost and labor for installing this option is a drawback. Bending conduit requires attention to control drawings and special tools for correct installation. Larger diameter bent conduit must be ordered in advance of installation for a correct fit around structures or machinery. Lighter weight, bendable conduit has little effective structural strength and is electrically conductive, so fasteners and seals are important for continuous and reliable service.

• Rigid non-metallic (polyvinyl chloride/PVC, HDPE, or other non-metallic material) conduit has a lower cost and ease of installation, but it is less durable at installation and afterwards. Most are rated for direct burial and in concrete. It has little effective structural strength and is not electrically conductive. Fasteners and seals are important for continuous and reliable service. Moisture intrusion at joints and difficulties with corner installation are drawbacks.

NOTE: For cost consideration, non-metallic rigid conduit may cost the least for initial installation, but replacement costs after destructive wear outweighs the initial cost savings.

Flexible Conduit Options

Since the 1920s, Underwriters’ Laboratories (UL) approved flexible conduit has proven effective for protecting residential and industrial wiring. Engineers choose UL listed, flexible conduit if installation must be inspected and modified due to changes in layout or power demand.

Due to variations in electrical conductivity of flexible conduit, code limits on more than six feet of length between junction boxes and grounding or bonding points is a consideration, if not a drawback. Electrical code allows for a variety of core and jacket materials. Flexible conduit is commonly used for electrical service amperage below 60 amps and under 1000 volts (dependent on conduit diameter and rating).

• Bare Flexible conduit (metal (FMC)) is suitable for confined spaces in walls, under floors or in overhead spaces where wiring needs to go around corners. This is often called Flex or Greenfield. It is suitable only for dry locations.
• Liquid tight conduit (metal (LFMC) or non-metallic (LFNC)) is suitable for confined spaces exposed to moisture, dirt or oil. UL listed fittings between conduit and junction boxes secure wiring from moisture and dust intrusion, enabling an effective path for grounding or bonding of metal conduit.

As the name suggests, flexible conduit can bend and flex without breaking, allowing for bending around corners without special tools. UL listed liquid tight conduit (LFMC) is also suitable for direct burial and in concrete.

NOTE: Some installations demand a combination of rigid metal and liquid tight flexible metal conduit to protect wiring in confined spaces. Shown here is an example of rigid metal and liquid tight conduit assembled for routing wiring around corners.

Some Additional Options to Consider

Recent electrical code updates allow more electrical conduit metal and jacket options.

• Stainless steel core metal and non-metallic flexible conduit, since it is not an effective conductor, requires a separate grounding conductor or bonding jumper. This may require three conducting wires instead of just two in the conduit.
• ANACONDA SEALTITE® Food Grade conduit and fittings meet CFR 21 and NSF 51 food safety requirements. This is suitable for connecting electricity to meat processing, pharmaceutical production and food service equipment.
• Halogen Free and Low Smoke liquid tight flexible conduit meets national safety requirements for installation in tunnels and confined spaces.
• Extreme temperature liquid tight flexible conduit is rated for high and low temperatures for installation in refrigerated or high heat locations including outdoors in harsh operating conditions.
• ANACONDA SEALTITE® Type ASUA conduit is UL listed and meets NEN-EN-IEC-600079-0 Section 26-13 anti-static surface resistivity requirement, suitable for protecting wiring in dusty locations.
• ANACONDA SEALTITE® Type UVUA conduit is UL listed and has extended resistance to UV (sunlight) degradation of the PVC jacket. This conduit jacket is suitable for outdoor use in prolonged sunlight or indoor use near UV sources.

Contact Anamet Electrical, Inc. To Choose The Right Conduit For Your Project

We are the world’s largest manufacturer and supplier of liquid tight, flexible conduit. Contact us when you are in doubt about which type of conduit to use for your project. Our team of experts will help guide you through the selection process and ensure that you choose the best conduit for your specific needs. Our goal is to help engineers deliver reliable service that stands the test of time.

How Deep Does Electrical Conduit Go?

Have you ever wondered how deep an electrical conduit needs to be buried? Or perhaps you’re undertaking a landscaping or construction project and need to know how deep to bury electrical conduit.

For safe electrical installation, these are crucial questions. We will provide guidance on how deep electrical conduits must be buried, based on various factors influencing the depth. Keep reading to learn more.

Start by planning to bury liquid tight conduit (LFMC or LFNC) 24 inches deep. This meets general National Electrical Code (NEC Article 300.5(A)) guidelines. Then consider the location and climate conditions where liquid tight conduit might be buried at a different depth.

The common reason for burying electrical wiring is to protect wiring from wind damage and exposure to extreme weather. However, regions that have extreme cold conditions (such as Alaska, Minnesota and parts of Canada) require deeper burial of building foundations, pipe and conduit.

NOTE: Before you dig, call local utilities. Utility personnel can identify underground utility lines and mark ground to make sure your digging is not dangerous.  

Understanding Electrical Conduit

Electrical conduit serves as protective piping for electrical wiring. Conduit can be metal or plastic and comes in different sizes to accommodate bundles of wire. The National Electrical Code (NEC) governs use of conduit, providing standards for how much wiring may fill the conduit and how many turns the conduit may take. If you install wiring, pulling wire through conduit is easier when there is plenty of space in the conduit, with few turns.

The primary function of conduit is wiring protection from elements like moisture, heat, corrosion or mechanical stress. Conduit shields wiring from abuse, preventing wiring from breaking, delivering a shock or causing a fire. Wiring protection is essential for electrical safety, so conduit is required in the building codes of most countries. Moreover, conduit can be a bonding or grounding device in an electrical system. Also, conduit organizes wiring so that  troubleshooting and repair is easier, allowing critical circuits to be routed through color conduit for quick identification in an emergency.

It’s important to carefully evaluate the specific location and environmental factors to ensure the best choice is made. Knowing how deep electrical conduits need to be buried is crucial to ensure electrical safety. Properly burying the conduit sustains wiring protection and makes repair or improvement easier.

Factors That Influence the Depth of Electrical Conduit

The depth at which electrical conduits must be buried varies by location and purpose. These include:

• Location: Different regions have types of soil that make deep burial difficult. Consult local authorities or building codes to determine the depth required for your specific location.
• Type of Conduit: We recommend liquid tight conduit, either metal conduit with a PVC cover (LFMC) or flexible non-metallic conduit (LFNC). We recommend UL listed liquid tight conduit, tested and proven for crush and corrosion resistance.
• Local Building Codes: Building codes protect owners from loss, making sure buildings can be insured and ensuring safety and reliability through years of use. It’s crucial to consult local building codes to determine the minimum burial depth required for your specific project.
• Plan ahead: Call your utility service to identify the location of existing lines. Measure twice and bury once. Make a straight shot between your power source and the intended outlet–fewer turns in the conduit make pulling wire easier. If providing temporary power for an above-ground pool or an outdoor grill, lightweight PVC LFNC may be all you need to bury to protect wiring for a summer. However, if you are planning on powering a new garage or outbuilding, install larger conduit that gives you flexibility and opportunity for upgrades, saving later expense.

How Deep Should You Bury Electrical Conduit?

As mentioned earlier, burial depth varies with conditions and locations. However, as a general rule, most safety codes require burial at 24 inches. This depth provides adequate protection and minimizes the risk of damage. Under concrete or roadways, conduit may be buried at 18 inches. However, local building codes may require a depth that avoids frost heave in areas with extreme temperatures and deep ground freezes.

It is worth noting conduit must be installed without crushing force, impact, water intrusion, corrosive chemicals or exposure to high heat. Even though LFMC and LFNC conduit is flexible, it can be damaged by abuse.

Your Go-To Partner for Secure and Smart Conduit Solutions

Understanding how deep electrical conduits must be buried is critical to any construction or landscaping project. The proper burial depth ensures the safety and longevity of the electrical system, minimizing the risk of accidents while ensuring compliance with building codes.

Ready to start your next project or need assistance with electrical conduit? Anamet Electrical, Inc. is here to help. Our sales representatives are near you, experienced and knowledgeable about local requirements. Contact us for more information, contact a sales representative or  request a quote today!

For an overview about the benefits and issues with Direct Burial, see the document What is Direct Burial?