1、 AN AMERICAN NATIONAL STANDARD NECA 101-2013 Standard for Installing Steel Conduits (Rigid, IMC, EMT) Published by National Electrical Contractors Association Jointly developed with Steel Tube Institute of North America Standard for Installing Steel Conduits (Rigid, IMC, EMT) NECA 101-2006 An Americ
2、an National Standard Published by National Electrical Contractors Association Jointly developed with Steel Tube Institute of North AmericaNOTICE OF COPYRIGHT This document is copyrighted by NECA Reproduction of these documents either in hard copy or soft (including posting on the web) is prohibited
3、without copyright permission. For copyright permission to reproduce portions of this document, please contact NECA Standards consult manufacturers listings and markings. 3. General Product Information Figure 1: Rigid Metal Conduit (RMC) (Courtesy of Allied Tube trade sizes 1/2, 1-1/2, 2-1/2, 3-1/2 a
4、re yellow; and trade sizes 3/4 and 1-1/4 are green. (See Table 1 on next page for Metric Trade Size Designators.) The nominal finished length of IMC with coupling is 3.05 m (10 ft). IMC has a reduced wall thickness and weighs about one-third less than RMC. The outside has a zinc based coating and th
5、e inside has an approved organic corrosion-resistant coating. IMC is interchangeable with steel RMC. Both have threads with a 1 in 16 taper (3/4-inch per foot); use the same couplings and fittings; have the same support requirements; and are permitted in the same locations. 3.1.3 Electrical metallic
6、 tubing - EMT (ferrous metal) NOTE: Aluminum EMT is not covered by this standard. Electrical Metallic Tubing (EMT), also commonly called thin-wall, is a listed steel raceway of circular cross section which is unthreaded, and nominally 3.05 m (10 ft) long (see Figure 3). 6.10 m (20 ft) lengths are al
7、so available. The outside corrosion protection is zinc based and the inside has an approved corrosion resistant organic coating. Trade sizes are 1/2 through 4. (See Table 1 on next page for Metric Trade Size Designators.) EMT is installed by use of set-screw or compression-type couplings and connect
8、ors. EMT is permitted to have an integral coupling which is comprised of a “belled” end of the tube with set screws (see Figure 4, next page). 3.1.4 PVC-coated conduit (See Section 6) 3.2 Manufactured Elbows, Nipples, and Couplings 3.2.1 Factory elbows Elbows are bent sections of conduit or tubing used to change raceway direction or bypass obstructions. IMC and RMC elbows are threaded on each end. Figure 2: Intermediate Metal Conduit (IMC) (Courtesy of Allied Tube & Conduit) Figure 3: Electrical Metallic Tubing (EMT) (Courtesy of Allied Tube & Conduit)
