• An electrical conduit system is a purpose-built piping system to house and protect electrical wiring. It serves several purposes: the organized routing of the enclosed wiring; protection from the elements, such as water and excessive heat; and protection from impact and chemical contamination. The use of conduits in wiring is required and specified in national wiring regulations.
  
  

Rigid Metallic Conduits (RMC)

• These threaded tubings made of stainless steel or aluminum feature thick walls and electromagnetic shielding. This protects the components inside from any outside electromagnetic interference in case of sensitive circuits as well as shielding the outside region from the emissions of the enclosed cables. These are used for long, straight sections of wiring, as mentioned on GlobalSpec's Electrical Components section.
  
  

Rigid Nonmetallic Conduits (RNC)

• RNCs offer the same functionality of housing long, straight lengths of cable as RMCs but don't offer any electromagnetic shielding. RNCs are used in wet areas where metal would potentially become corroded.
  
  

Galvanized Rigid Conduits (GRC)

• These metallic conduits are identical to RMCs except for a zinc coating over their metal body, which increases their resistance to abrasion and corrosion, making them suitable for use in wet or corrosive areas where there is a strict requirement to use metallic conduits, such as for electromagnetic shielding. GRCs are more expensive than RMCs and RNCs.
  
  

Electric Metallic Tubing (EMT)

• This non-threaded, thin-walled tubing of coated steal is often used instead of GRC because it is cheaper and weighs less. It offers the features of GRC but to a lesser degree due to differences in the thickness of the metal. An EMT is relatively less resistant to corrosion but makes up for it by being flexible enough to bend and form, and it is easier to cut.
  
  

Electric Nonmetallic Tubing (ENT)

• This corrugated, thin-walled tubing is circular, flexible and moisture-resistant. The material used is flame-retardant, making it common for installation in fire-hazard areas.
  
  

Flexible Metal Conduit (FMC)

• These highly flexible conduits are made from ribbed aluminum or steel strip coiling and are used in dry areas where bending is required--around columns and corners and often at the ends of rigid conduits.
  
  

Liquid-tight Flexible Metal Conduit (LFMC)

• These conduits feature a liquid-tight, non-metallic coating around an FMC and are used underwater. Their non-metallic counterparts are the liquid-tight nonmetallic metal conduits (LNFC), which are also fire-resistant and are often used in wet areas with a fire hazard, such as certain chemical plants.
  
  

Fittings

• Various types of special connector fittings are used to connect the conduits. These could be made from metal to go with metallic conduits, or from non-metallic material to connect non-metallic conduits. Fittings are non-flexible and of several types, including a bar to connect a conduit to a junction or electrical box; coupling for connecting two conduits together and L, T, and C junctions to tackle bends, splits and curves in wiring.