Electrical Metallic Tubing
( E M T )
 
  Galvanized Rigid Steel
Conduit ( R S C )
 
  Intermediate Metal
Conduit ( I M C )
 
  Fittings & Couplings
( F C )
   


*General

The above specs may still be referenced, however the federal government has canceled it and has adopted the UL 1242 standards

*Application

IMC can be installed indoors or outdoors, exposed or concealed, in all kinds of atmospheric conditions, and in hazardous locations, when in accordance with NEC? 2002 Article 344. Also, it provides mechanical protection for the conductors while reducing Electro-Magnetic Field (EMF) exposure and shielding against Electro-Magnetic Interference (EMI).

IMC has a reduced wall thickness, when compared to RSC, and weighs about one-third less than RSC. The outside has a galvanized coating for corrosion protection and the inside has an approved organic corrosion-resistant coating. IMC is interchangeable with galvanized rigid steel conduit. Both have threads with a 3/4-inch per foot taper, use the same couplings and fittings; have the same support requirements; and are permitted to be used in the same locations. Requires approximately 33% less steel than conventional steel Rigid Conduit

IMC is an approved equipment grounding conductor under the 2002 NEC? Section 250.118. The NEC? establishes the minimum requirements for the safe electrical installation. Because of the varied environments in which electrical equipment is installed, local amendments are often added. Always consult local codes prior it any installation.


IMC is a lighter-weight, thinner wall alternative to rigid steel conduit. Covered under Article 342 in the NEC?, IMC is a listed threaded steel raceway of circular cross section with a coupling which can be either a standard straight-tapped conduit coupling or the integral type. Threads on the uncoupled end are covered by industry color-coded thread protectors which protect the threads, keep them clean and sharp, and aid in trade size recognition. IMC is available in trade sizes 1/2 through 4. Thread protectors for trade sizes 1, 2, 3, 4, are color-coded orange; trade sizes 1/2, 1 1/2, 2 1/2, 3 1/2 are yellow; and trade sizes 3/4 and 1 1/4 are green. The nominal finished length of IMC with coupling is 10 feet. HOT ZINC COATED. Special clear secondary coating applied after galvanizing provides added corrosion protection IMC is produced by a continuous weld-galvanizing method using the most modern mills and Hot Galvanizing process.

*Specifications

IMC should be mild steel, manufactured, hot-dipped galvanized, and produced to the following specifications:

ANSI, C80.6- American National Standard for Electrical Intermediate Metal Conduit; UL 1242- UL Standard for Electrical Intermediate Metal Conduit; NEC 2002 Article 342
(1999 NEC article 345); WW-C 581 (Class 2Type A)-Federal Specification


Intermediate Metal Conduit (IMC) - Weights and Dimensions

Tolerance is same as corresponding size of rigid conduit.