Flexible Metal Conduit (FMC) is a popular choice in many electrical installations, so understanding its proper applications is crucial. In this blog, we'll explore where FMC can and cannot be used.

Permitted Uses

FMC offers great versatility as it is permitted to be used in both exposed and concealed locations. This makes it suitable for a wide range of projects, whether you're working on a residential or commercial electrical setup. Its flexibility allows for easy installation around corners and in tight spaces, which is a significant advantage in many construction scenarios.

Not Permitted Uses

1. Wet Locations: Moisture can be a conduit's worst enemy. FMC should not be used in wet areas as it can lead to corrosion and damage to the conductors inside, posing a safety and functionality risk.

2. Hoistways (Except as Permitted in 620.21(A)(1)): Hoistways have specific safety requirements, and in most cases, FMC is not suitable due to potential hazards related to its use in these high - traffic and safety - sensitive areas.

3. Storage Battery Rooms: The environment in storage battery rooms can be corrosive, with the presence of chemicals and gases. FMC is not designed to withstand such conditions, so it's a no - go in these areas.

4. Hazardous (Classified) Locations (Except as Permitted by Other Articles in the Code): Hazardous locations require special types of conduits to prevent sparks and other potential ignition sources. FMC, in general, is not approved for these areas, except when explicitly allowed by other code articles.

5. Exposure to Deteriorating Materials: Materials like oil or gasoline can break down the integrity of the conductors in FMC. Therefore, it should not be used in areas where it will be exposed to such substances.

6. Underground or Embedded in Poured Concrete or Aggregate: Underground conditions and being embedded in concrete or aggregate can subject FMC to excessive pressure and moisture, making it an unsuitable choice for these applications.

7. Areas Subject to Physical Damage: FMC may not be able to withstand physical abuse, so in areas where it is likely to be hit, crushed, or otherwise damaged, it should not be installed.

By being aware of these permitted and non - permitted uses, you can ensure the safe and effective use of FMC in your electrical projects. Remember, following these guidelines not only ensures the proper functioning of your electrical system but also enhances safety.

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