Metallic vs Non-Metallic Conduits: A Comprehensive Guide

Flexible conduit is pipe or tubing used to protect and route electrical wiring in a structure. They can be various materials, including metal or plastic.

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There are two main types of conduit: metallic and non-metallic. Each has advantages and disadvantages to consider while choosing conduit for a particular application.

Metal conduit is usually made of aluminum or steel. It is strong and durable, making it ideal for applications requiring mechanical protection for wiring. However, metal conduit is more expensive than a non-metallic conduit and is subject to corrosion.

Non-metallic conduit is made of plastic, such as PVC or HDPE. Non-metallic conduit is less expensive than a metallic conduit and is not subject to corrosion. However, non-metallic conduit is not as strong or durable as metallic conduit and may not provide the same level of mechanical protection.

When choosing between metallic and non-metallic conduits, it is essential to consider the application&#;s specific needs. Cost, durability, flexibility, weight and temperature or corrosion resistance are important factors to consider. The right type of conduit will depend on the application&#;s particular requirements.

Now, let&#;s dive into the similarities between the two conduits.

Similarities among a metallic conduit and a non-metallic conduit

Metallic conduit and non-metallic conduit have these similarities:

• Both are composed of materials that are strong and durable, making them ideal for electrical wiring applications.
• Both types of conduit are designed to protect and route electrical wiring.
• Both metallic and non-metallic conduit are available in various common Trade sizes to accommodate different applications.
• Both are suitable for use in domestic, commercial, and industrial buildings and structures.
• Both protect against fire, mechanical damage and corrosion.
• Both may be rated for electrical safety applications according to the National Electrical Code (NEC).
• Both have adequate electrical field shielding and flexural stiffness (resistance to deformity).

Differences between metal conduits and non-metal conduits

Here are key differences between metal and non-metallic conduit to consider:

Non-metallic conduit

Here are some of the advantages of using non-metallic conduit:

• It can be used for fixture whips, data centers, electric signs and outdoor lighting, HVAC, pool and spas, and locations with exposure to sunlight and weather conditions.
• It is less expensive than most metal conduit.
• It is easy to cut at the site of installation.
• It is lighter weight than most metal conduit.
• It is more flexible than most metal conduit, making it easier to route through tight spaces.
• It may be installed in wet locations and buried in the ground or in concrete.
• It may be installed indoors, outdoors, under ground and above ground.
• PVC conduit may be recycled multiple times.

Here are some disadvantages in use of non-metallic conduit:

• It is not as resistant to crushing force, even though it may rebound from impact.
• Most non-metallic conduit is not rated for high or low temperature extremes
• It is not permitted in hazardous areas where the ambient temperature exceeds 50°C (122°F) or in applications where the conductor insulation temperature exceeds the rated temperature, such as extreme cold.
• It cannot be installed in plenum environments due its flammability and possibility for generating toxic smoke or fumes in a fire.
• It cannot be used without physical support along its installed length.

Metallic conduit

The following are the advantages of using metal conduits:

• Metal conduit is durable and can last many years with proper maintenance.
• Galvanized steel, aluminum, stainless steel, bronze and brass conduit is recyclable, making them a more sustainable option than other materials.
• It can withstand extreme temperatures and conditions, making it an ideal choice for protecting electrical wiring in harsh operating environments.
• It is resistant to impact and temperature changes, making it an ideal choice for protecting wiring in high-traffic areas or areas subject to extreme temperatures.
• It is made of non-combustible material, making it an excellent choice for protecting wiring for fire safety applications.
• It can be rated for electrical safety applications.
• A metallic conduit is easy to machine or fabricate, making it ideal for applications that require custom sizes or shapes.
• Extruded polymer jackets meet or exceed industrial chemical resistance requirements.
• Polymer jackets provide liquid tight protection allowing installation in wet conditions, or burial underground or in concrete.
• Polymer jackets provide low smoke or Halogen free protection of wiring.
• A integral bonding wire may be included in metal conduit, supporting NEC approved use in electrical connections.

However, using a metallic conduit also has some disadvantages, including:

• It costs more upfront to purchase the materials and install them.
• It does not offer full protection for circuits above and below ground against hazards, without a liquid tight jacket.
• It is heavier than a non-metallic conduit.

Flexible metallic & non-metallic conduits from Anamet Electrical

Key differences in these conduit types is material, durability and cost.

Metal conduit is more expensive than non-metallic conduit but it offers better protection from fire, pests, and extreme temperatures. They are also more durable and have a longer lifespan.

Non-metallic conduit is made of plastic or other material, less durable than metal. However, is it less expensive, lighter weight, more flexible and more corrosion resistant.

Anamet Electrical, Inc. has over 100 years of experience manufacturing quality flexible conduit for electrical wiring. Our liquid-tight metal and non-metallic conduit types are available for protecting mission-critical wiring from harsh operating conditions on land, at sea and in the air.

Our flexible metallic conduit and non-metallic conduit are available in various sizes and lengths. They can be custom-ordered to meet your specific needs.

If you&#;re looking for a high-quality, reliable, and durable conduit solution, look no further than Anamet Electrical. Contact us today to learn more information about our products and services.

If you are looking for more details, kindly visit PU Jacket Flexible Metal Conduit supplier.

2 Comments

1. John K. Boren

   May 14, at 9:39 pm

   Can flexible metal conduit (FMC) be used to facilitate a power drop in an industrial facility? Can it support its own weight, as it will be hanging from the rafters.

   • Jonathan Middleton

     May 17, at 4:53 pm

     We cannot recommend free hanging flexible conduit. We can&#;t know how much motion, strain or strain relief your application would cause or allow.
     Please see National Electrical Code Article 350.30 Securing and Supporting LFMC, with support required every 4-1/2 feet, no definition between vertical or horizontal.
     Check with your local code inspector for variance.

By Jeff Battani, Product Line Manager ABB Installation Products Division and 
Bogdan Diaconescu, Product Manager ABB Installation Products Division    

Flexible Conduit Systems are designed to provide the very same cable protection solutions as Rigid Conduit Systems- protecting cables, conductors and wiring within industrial, commercial and even residential applications. The main difference between Rigid and Flexible Systems is how they are applied in a variety of applications and installations.   

What are Flexible Conduits? 

The reference to &#;flexible&#; is associated with the Liquid-tight Flexible Metallic Conduit (LFMC), that provides the electric raceway solutions specified in Article 350 of the NEC. Product requirements for the LFMC are covered in UL 360, while Conduit Fittings meet the requirements of UL 514B.  Together UL 360 and UL 514B outline the product characteristics and test requirements for listed LFMC and conduit fittings. These standards are used to evaluate the products for performance characteristics such as impact, crush resistance, ingress ratings, temperature, strength, bending, flexibility, flammability and more. 

Liquid-tight Flexible Metal Conduit is constructed of a spiral core that typically consists of galvanized steel. Other conduit core types include brass, aluminum and stainless steel, each having specific characteristics for specific application requirements. The spiral wound core allows for flexibility while providing mechanical protection of the conductors and cables that it will carry. The core design, materials and trade sizes, all have influence on the conduit&#;s flexibility in either static or dynamic applications.  The jacket materials typically consist of PVC, but may include thermoplastic rubber, polyurethane or PA nylons.  

Flexible Conduit Systems are typically used in installations where flexibility is required to make connections, and where the installation may be subjected to shock and vibration. Product selection should take into consideration: 

• The specific application and industry requirements 
• System temperature ratings 
• System ingress ratings Indoor or outdoor installations
•  Approvals/certifications 
• Reliability of performance over time.   

Considerations for Rigid Conduit 

When electrical wires and circuitry need mechanical protection and support in an industrial electrical installation between two points, one of the common methods used is rigid Conduit Systems. Typically, rigid metal conduit is heavy-duty galvanized steel tubing installed with threaded fittings. In some applications, rigid conduit may be aluminum. Rigid conduit is commonly used outdoors to provide solid protection from damage caused by the elements or mechanical impacts. They can also provide structural support for electrical cables, panels, and other equipment. An added feature of a rigid metal conduit system is that it can be direct buried and encased in concrete. It may also serve as a useful bonding conductor for grounding (NEC &#;250.118(2)).  

When transporting and protecting live electrical wires over long distances through various parts of an industrial facility, there are always two major concerns for the engineers designing the systems: (i) risk of fire and (ii) electromagnetic interference. In both instances, metal rigid systems provide an excellent choice offering exceptional fire resistance and reduction of electromagnetic fields&#;by as much as&#;95%. 

In addition to use in ordinary environments, the rigid system solution is well suited for harsh environments. For instance, in an industrial environment where corrosive factors such as salinity and various chemical agents are prevalent, the metal rigid system can be fully coated with a layer of PVC, offering significantly increased protection and extension of the life of the electrical system. Similarly, in hazardous environments such as exists in many applications in the Oil & Gas facilities, Chemical Plants, Metal and Mining extraction, Pulp and Paper and other industries, rigid metal conduit will not permit the flow of flammable gases and vapors,  providing protection from fire and explosion hazard when installed with proper sealing fittings. The threaded ends of the rigid conduits offer both a flame path to prevent explosions and a proven way to cool off any gases that may escape the closed system. 

What if both Rigid and Flexible Cable Protection are needed? 

Many applications and installations will require transition solutions between Rigid and Flexible Cable Protection Systems. These transition solutions must deliver continuity of performance, ratings, approvals and specification requirements. When selecting transition solutions, these key factors should be considered: 

• System Materials & Corrosion Protection: Rigid and Flexible systems are specified by the installation requirements including environment, applications and installation environment. Steel, aluminum, stainless steel and coated solutions are available for both rigid and flexible components required for a complete installation solution.  
• System Ingress Ratings: Both Rigid and Flexible systems carry Ingress Ratings that meet UL, CSA, NEMA and IEC IP ratings. These ingress ratings ensure that the total system will perform for dust tight, liquid tight, rain tight and temporary submersions requirements. A clear understanding of the ingress requirements of the installation is needed to select products that have appropriate listed and certified ingress ratings. to help ensure the ingress integrity of the complete installation between cable protection systems, enclosures and control gear. 
• System Temperature Ratings: Rigid conduits systems inherently have very high temperature ratings for non-coated and coated products. Flexible conduit systems now offer dedicated High Temperature (HT) solutions, from -60 to +150°C (-72 to +302°F). 
• Transition of Trade Sizes: Based on the installation requirements, conduits and fittings may need to transition between different trade sizes.  For example, a system may need to transition from a 1&#; rigid body to a 3/4&#; flexible conduit and fitting.  These transition requirements can be easily resolved with the use of &#;enlargers&#; or &#;reducers,&#; available in many size combinations and materials.   
• Transition of Thread Types: In some applications, transitions may be required between different thread types including NPT, ISO Metric, PG and other thread types. When these applications are encountered, &#;thread converters&#; can be applied to make these transitions.   
• Approvals & Certifications: Selection of products that carry the appropriate listings, certifications and approvals will help provide an installation that performs safely and reliably.  

Key Points to Remember  

• Rigid and Flexible Conduit Systems can be used together, to provide a high performance and reliable cable protection solution over the life of the installation. 
• When specifying cable protection solutions, consider all application and installation requirements including: environment, materials, corrosion protection, temperature ratings, ingress ratings, approvals/certifications, etc. 
• Transitioning between Rigid and Flexible Systems can be accomplished with the correct reducers, enlargers and thread converter accessories.  
• All cable protection products must be applied according to national and local electrical codes and standards.  

Additional information 

Additional information: T&B Liquidtight Systems 
https://new.abb.com/low-voltage/products/conduit-fittings/liquidtight-systems   

T&B Liquidtight Systems E-Catalog  (link to catalog)   

Rigid Conduit Systems
https://new.abb.com/low-voltage/products/conduit-fittings/rigid 

For more information, please visit PU Jacket Flexible Metal Conduit wholesaler.