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Flexible Metal Conduit

Flexible metal conduit (FMC) has a spiral construction that enables it to snake through walls and other structures. FMC protects electrical wiring in commercial and industrial buildings. Liquidtight flexible metal conduit (LFMC) is a special type of FMC that has a plastic coating. When used with sealed fittings, it becomes watertight.

Products include all types of FMC and LFMC identified in the National Electrical Code? (NEC) and complies with Underwriters Laboratories (UL) and CSA Standard UL 360/CSA C22.2 No. 56-17 Flexible Metal Conduit and Liquid-Tight Flexible Metal Conduit.

NEMA Members promote the development of application and installation guidelines for FMC, and successfully proposed to UL a sample selection for qualification testing of LFMC jacketing materials.


  • Maintains active involvement with UL and the National Fire Protection Association (NFPA), which publishes the NEC; develops and advocates for public inputs for the NEC
  • Promotes harmonization of UL, CSA, and ANCE (Mexican Association for Standardization and Certification Standards) for FMC and LFMC
  • Spearheaded adoption of NFPA 130 as NEMA Engineering Bulletin 115 to reinstate the permitted use of jacketed LFMC in rail tunnels and stations
  • Educates electricians and others on proper cutting and terminating of FMC and LFMC; develops training modules based on NEMA RV 3 Application and Installation Guidelines for Flexible and Liquidtight Flexible Metal and Nonmetallic Conduits to include LFNC


  • FMC and LFMC: construction of commercial and industrial properties
  • Standard FMC: dry indoor locations, often for short runs between a wall box and a motor or fixed appliance (e.g., garbage disposal)
  • LFMC: outdoor equipment (e.g., air conditioner units)


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