Flexible metal conduit (FMC) is a spirally damaged flexible pipe, usually made of aluminum. FMC has fairly limited uses because it cannot be used outdoors or in other wet areas. However, it is the clear choice in some applications. Non-metallic conduit is typically made of PVC and is ideal for outdoor residential applications. Blue Electrical Non-Metallic Conduit (ENT) is for indoor use only. Some code-compliant PVC fittings are available for ENT interior walls, floors, some ceilings, or encased in concrete.
Key Facts
- Liquid-tight Flexible Metal Conduit (LFMC): LFMC is a type of flexible metal conduit that has a waterproof sheath. It is designed to provide flexibility and protection from moisture, making it suitable for outdoor use and exposure to hazardous areas.
- Precautions for Outdoor Use: When using flexible metal conduit outdoors, it is important to take certain precautions to ensure the safety of the electrical system and the people using it. These precautions include:
- Choosing waterproof metal conduit: To prevent water damage, it is recommended to use waterproof metal conduit. Water entering the conduit can cause corrosion and lead to electrical shorts and other issues.
- Proper sealing: If waterproof metal conduit is not used, it is important to ensure that the conduit is properly sealed. Any openings or joints should be sealed with waterproofing materials to prevent water from entering.
- Protection against physical damage: While flexible metal conduit is durable, it can be damaged if subjected to excessive force or impact. Properly supporting the conduit and avoiding heavy loads or impact can help prevent physical damage.
- Grounding and bonding: Proper grounding and bonding of the flexible metal conduit to the electrical system is important to protect against electrical shocks and other hazards, especially in outdoor environments where lightning and other electrical hazards may be present.
- Compliance with codes and regulations: It is crucial to follow all relevant codes and regulations when installing and using flexible metal conduit outdoors. This includes ensuring that the conduit is rated for outdoor use, properly sized and installed according to code, and properly marked and labeled.
Liquid-tight Flexible Metal Conduit (LFMC)
LFMC is a type of flexible metal conduit that has a waterproof sheath. It is designed to provide flexibility and protection from moisture, making it suitable for outdoor use and exposure to hazardous areas.
Precautions for Outdoor Use
When using flexible metal conduit outdoors, it is important to take certain precautions to ensure the safety of the electrical system and the people using it. These precautions include:
Choosing waterproof metal conduit:
To prevent water damage, it is recommended to use waterproof metal conduit. Water entering the conduit can cause corrosion and lead to electrical shorts and other issues.
Proper sealing:
If waterproof metal conduit is not used, it is important to ensure that the conduit is properly sealed. Any openings or joints should be sealed with waterproofing materials to prevent water from entering.
Protection against physical damage:
While flexible metal conduit is durable, it can be damaged if subjected to excessive force or impact. Properly supporting the conduit and avoiding heavy loads or impact can help prevent physical damage.
Grounding and bonding:
Proper grounding and bonding of the flexible metal conduit to the electrical system is important to protect against electrical shocks and other hazards, especially in outdoor environments where lightning and other electrical hazards may be present.
Compliance with codes and regulations:
It is crucial to follow all relevant codes and regulations when installing and using flexible metal conduit outdoors. This includes ensuring that the conduit is rated for outdoor use, properly sized and installed according to code, and properly marked and labeled.
Sources
- Can flexible metal conduit be used outdoors?
- Precautions for Outdoor Use of Flexible Metal Conduit
- Sealproof 1/2-Inch Flexible Nonmetallic Liquid-Tight Electrical Conduit Type B, UL Listed, 1/2″ Dia, 25 Feet, Made in USA
FAQs
Is flexible conduit waterproof?
Not all flexible conduits are waterproof. Liquid-tight Flexible Metal Conduit (LFMC) is a type of flexible metal conduit that has a waterproof sheath, making it suitable for outdoor use and exposure to moisture.
What are the precautions for using flexible metal conduit outdoors?
When using flexible metal conduit outdoors, it is important to take certain precautions to ensure the safety of the electrical system and the people using it. These precautions include choosing waterproof metal conduit, properly sealing the conduit, protecting it against physical damage, grounding and bonding the conduit, and complying with all relevant codes and regulations.
What is the difference between LFMC and FMC?
LFMC (Liquid-tight Flexible Metal Conduit) has a waterproof sheath, making it suitable for outdoor use and exposure to moisture. FMC (Flexible Metal Conduit) does not have a waterproof sheath and is not suitable for outdoor use or in other wet areas.
What are some applications of LFMC?
LFMC is used in various applications, including outdoor lighting, signage, industrial machinery, and marine environments. It is also used in hazardous areas where protection from moisture and chemicals is required.
What are some applications of FMC?
FMC is used in various applications, including indoor wiring, control panels, and machine tools. It is also used in commercial and industrial settings where flexibility and protection from abrasion are required.
What are the advantages of using flexible conduit?
Flexible conduit offers several advantages, including easy installation, flexibility, and protection of wires and cables. It is also lightweight and resistant to corrosion and chemicals.
What are the disadvantages of using flexible conduit?
Flexible conduit also has some disadvantages, including its higher cost compared to rigid conduit, its susceptibility to damage if not properly installed, and its potential to become a tripping hazard if not properly secured.