The term “electrical conduit” refers to tubing or enclosures used to protect and provide a route for individual electrical wiring conductors.Where wiring is exposed or subject to damage is where conduit is required.A conduit can be made of metal or plastic.The electrical boxes are usually made of the same or similar material as the conduit.All applicable local code rules must be followed when installing conduit.
There are seven different types of conduit.
There is a heavy-duty galvanized steel tubing that is installed with threaded fittings.It can provide structural support for electrical cables, panels, and other equipment when used outdoors.RMC is sold in lengths of 10 and 20 feet.
IMC is a thinner, lighter-weight version of rigid metal conduit that is approved for use in all of the same applications.In new construction, IMC is more common because it is lighter and easier to work with.
An example of a rigid electrical conduit is EMT, which is made of galvanized steel but can also be aluminum.EMT is called “thin-wall” conduit because it is lightweight and thin.EMT can be bent with a simple tool.
EMT is secured with set screws or compression-type bolts.The tubing is not threaded like RMC and IMC.EMT sizes range from 1/2 inch to 1 inch.It is used in residential and light commercial construction.It must be assembled in a special way if it is to be installed outdoors.
Flexible corrugated plastic tubing that is flame-retardant is called electrical nonmetallic tubing.It is easy to bend and install.Non-metallic tubing can’t be installed in exposed locations so it’s used inside walls.ENT can be installed inside concrete block structures and can also be covered with concrete.ENT is named after the Smurfs cartoon characters due to the blue color of the conduit.
“Greenfield” is the name of the FMC and its inventor.It can snake through walls and other structures because of its spiral construction.Standard FMC is used in dry indoor locations for short runs between a wall box and a motor or fixed appliance.
Liquid-tight flexible metal conduit is a type of conduit that has a plastic coating and is sealed to make it waterproof.It is used with outdoor equipment.
Similar to plastic plumbing pipe, rigid polyvinylchloride is installed with plastic fittings that are glue in place.It can be bent after being heated.The conduit assembly can be watertight, making it suitable for direct burial in the ground for many applications.In corrosive environments, it is allowed.