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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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