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Steel Conduit and Electrical Metallic Tubing


Steel conduit and electrical metallic tubing (EMT) refers to the steel-based durable enclosures that route individual electrical wiring conductors in a building or structure and protect the wires from impact, moisture, and chemical vapors.

Conduit systems are classified by wall thickness, mechanical stiffness, and material used. Rigid metal conduit (RMC) is a thick-walled threaded tubing, usually made of coated steel, stainless steel, or aluminum. Galvanized rigid conduit (GRC) is galvanized steel tubing, with a tubing wall that is thick enough to allow it to be threaded. Intermediate metal conduit (IMC) is a thinner, lighter-weight version of RMC. Polyvinyl chloride (PVC)–coated steel conduit is used for highly corrosive environments. Related products include conduit and associated elbows, threaded couplings, and nipples.

Since conduit must be installed in accordance with the National Electrical Code® (NEC) and all applicable local regulations, Members develop proposals for the NEC, International Code Council codes, and other codes.

Activities

  • Develops, revises, and manages NEMA Standards, technical bulletins, and user guides related to conduit and electrical metallic tubing, and provides input on Underwriters Laboratories (UL) Standards for steel conduit
  • Participates in the American National Standards Institute (ANSI) Accredited Standards Committee on electrical rigid steel conduit, electrical metallic tubing, electrical rigid aluminum conduit-aluminum, and intermediate metal conduit.
  • Maintains work of CANENA (Council for Harmonization of Electrotechnical Standards of the Nations in the Americas) Technical Harmonization Subcommittee
  • Maintains NEMA Field Representative presentations on Grounding; Evaluation of Steel Conduit and EMT as Equipment Grounding Conductors, Corrosion Protection; and UL & NEC Requirements for Corrosion Protection of RMC, IMC, EMT

Applications

  • Direct encasement in concrete
  • Electrical and communication outlet installation the middle of large open areas
  • Protecting conductors against fire damage
  • Protecting sophisticated control systems wiring
  • Shielding sensitive circuits from electromagnetic fields (EMF) and electromagnetic interference (EMI), and preventing emission of such interference from enclosed power cables
  • Waterproof or submersible conduit system

Resources

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