The National Electrical Code (NEC) once restricted the length of flexible metal conduit (FMC) to 6 feet for specific applications like lighting fixtures and motor leads. However, this restriction has been eliminated from the Code in recent revisions. Therefore, there is no specific length limit for flexible conduit in general.
Key Facts
- Length Limitations: The National Electrical Code (NEC) used to restrict the length of flexible metal conduit (FMC) to 6 feet for specific applications, such as lighting fixtures and motor leads. However, this limitation has been removed from the Code in recent revisions. Therefore, there is no specific length limit for flexible conduit in general.
- Grounding Requirements: If the length of the flexible conduit exceeds 6 feet, it is necessary to install a separate equipment grounding conductor. This ensures proper grounding and safety.
- Support and Installation: Flexible conduit, regardless of its length, must be properly supported and installed according to the NEC rules. This includes supporting the conduit within 12 inches of any termination and at intervals not exceeding 4.5 feet.
- Specific Cases: While there is no general length limit for flexible conduit, there are some specific cases where limitations still apply. For example, lighting fixture tap conductors must be limited to 6 feet in length. Additionally, certain rules may apply to specific trade sizes or types of conduit.
Grounding Requirements
When the length of the flexible conduit exceeds 6 feet, a separate equipment grounding conductor must be installed. This ensures proper grounding and safety.
Support and Installation
Regardless of its length, flexible conduit must be properly supported and installed according to the NEC rules. This includes supporting the conduit within 12 inches of any termination and at intervals not exceeding 4.5 feet.
Specific Cases
While there is no general length limit for flexible conduit, some specific cases still have limitations. For instance, lighting fixture tap conductors must be limited to 6 feet in length. Additionally, certain rules may apply to specific trade sizes or types of conduit.
Conclusion
In general, there is no specific length limit for flexible metal conduit as per the NEC. However, it is crucial to follow the Code’s requirements for grounding, support, and installation. Additionally, specific cases may have limitations, such as lighting fixture tap conductors, which must be 6 feet or less in length.
References
- Lengths and Limitations for FMC and LFMC
- Does the NEC Limit a Flexible Metal Conduit Run?
- Flexible metal conduit length?
FAQs
Is there a general length limit for flexible conduit?
No, there is no specific length limit for flexible conduit as per the National Electrical Code (NEC).
When is a separate equipment grounding conductor required for flexible conduit?
If the length of the flexible conduit exceeds 6 feet, a separate equipment grounding conductor must be installed.
What are the support and installation requirements for flexible conduit?
Flexible conduit must be properly supported and installed according to the NEC rules. This includes supporting the conduit within 12 inches of any termination and at intervals not exceeding 4.5 feet.
Are there any specific cases where length limitations apply to flexible conduit?
Yes, there are some specific cases where limitations still apply. For example, lighting fixture tap conductors must be limited to 6 feet in length. Additionally, certain rules may apply to specific trade sizes or types of conduit.
What are some additional considerations when using flexible conduit?
When using flexible conduit, it is important to consider factors such as the type of application, environmental conditions, and the NEC requirements for the specific installation.
Can flexible conduit be used outdoors?
Yes, flexible conduit can be used outdoors, but it must be listed for outdoor use and properly installed to protect it from moisture and other environmental factors.
What are some common applications for flexible conduit?
Flexible conduit is commonly used in residential, commercial, and industrial applications. It is often used for connecting lighting fixtures, motors, and other electrical equipment.
What are the advantages of using flexible conduit?
Flexible conduit offers several advantages, including ease of installation, flexibility in routing, and protection of conductors from physical damage.