Electrical Metallic Tubing (EMT) is lightweight steel tubing that is easy to install and can be bent or cut with the appropriate tools. EMT conduit is more affordable than IMC or GRC, but its thin walls are more easily punctured. It is most often used in dry interior spaces, but can be used in damp locations with corrosion-resistant hardware and rain-tight fittings.
Flexible Metal Conduit is easy to install and has a spiral construction for a high degree of flexibility. Commonly referred to as “Greenfield,” it’s useful in places where rigid conduit is difficult to install. It’s also a good choice for vibrating equipment, such as heating and air conditioning units.
Galvanized Rigid Conduit (GRC) offers the highest level of protection at a higher cost. Available in galvanized aluminum, galvanized steel and stainless steel, it’s good for straight runways. Its threaded ends require threaded fittings. This rigid metal conduit is approved for all interior applications but can also be used outside.
Liquid Tight Conduit is available in both metallic and nonmetallic configurations; the metallic configurations generally have a plastic coating to prevent water from penetrating. It protects wires from moisture and is intended for use in wet or corrosive locations indoors and out.