ANSI C-80.3-2005 pdf download American National Standard for Steel Electrical Metallic Tubing (EMT)、
1 Scope This standard covers the requirements for steel electrical metallic tubing, for use as a raceway for wires or cables of an electrical system. Finished tubing is typically furnished in nominal 10 ft (3.05 m) lengths. It is protected on the exterior surface with a metallic zinc coating or alternate corrosion protection coating (see UL 797 Eighth edition Clauses 5.3.3, 6.2.4, 7.5 and 7.6) and on the interior surface with a zinc or organic coating. This standard also covers electrical metallic tubing elbows. Properly assembled systems of steel electrical metallic tubing and elbows, manufactured in accordance with this standard, and other identified fittings provide for the electrical continuity required of an equipment grounding conductor.
2 Normative References The following standards contain provisions which, through reference in this text, constitute requirements of this American National Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this American National Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below unless otherwise specified.
ASTM A 239 – 95 (1999), Standard Practice for Locating the Thinnest Spot in a Zinc (Galvanized) Coating on Iron or Steel Articles
ASTM B 499 – 96 (2002), Standard Test Method for Measurement of Coating Thicknesses by the Magnetic Method: Nonmagnetic Coatings on Magnetic Basis Metals
UL 797, Electrical Metallic Tubing — Steel
3 Definitions
3.1 Electrical metallic tubing (EMT): A steel raceway of circular cross-section designed for the physical protection and routing of conductors and cables for use as an equipment grounding conductor.
3.2 Elbow: A manufactured curved section of EMT.
3.3 Alternate corrosion resistant coating (ACRC): A coating(s), other than one consisting solely of zinc, which, upon evaluation, has demonstrated the ability to provide the level of corrosion resistance required on the exterior of tubing. It is not prohibited that the coatings include zinc. (See UL 797 Eighth edition Clauses 5.3.3, 6.2.4, 7.5 and 7.6.)