The Plastics Pipe Institute (PPI) and the National Electric Manufacturers Association (NEMA) recently unveiled the revised NEMA TC 7-2013, “Smooth Wall Coilable Electrical Polyethylene Conduit.” Members of the Conduit Division of the PPI provided critical assistance in revising the standard to bring it up to current industry requirements.
TC 7 includes trade sizes ranging from ½ in. to 8 in. diameter. In addition, there are five electrical polyethylene conduit (EPEC) wall types, including: EPEC 17 (SDR 17), EPEC 13.5 (SDR 13.5), EPEC 40 (Schedule 40), and EPEC 80 (Schedule 80). The newest wall type added to this version is EPEC 11 (SDR 11). There are two key changes for testing in the latest version of TC 7:
1. A new test for pipe stiffness has been added to the standard conducted in accordance with ASTM D 2412, “Determination of External Loading Characteristics of Plastic Pipe by Parallel-Plate Loading.” To learn more about the significance of this test requirement, download and review TR 47 from the publications section of PPI’s website.
2. The traditional “crush test” has been changed to a visual pass/fail and recovery test for evaluating the finished conduit’s ductility.
To order an electronic or hard copy of NEMA TC 7-2013, please visit NEMA’s website.
