Posted 10 Nov 2010 What charts do you guys use to determine wire size in wire duct? Share this post Link to post Share on other sites
Posted 10 Nov 2010 Panduit http://www.panduit.com/Support/DesignTools/index.htm Share this post Link to post Share on other sites
Posted 11 Nov 2010 Hm I'm not too sure what these tools do. They don't give much explanation on the website. To be more clear tables like NEC 310.16 and 310.17 are for not more than three conductors in a raceway or conduit and a single conductor in free air respectively. The UL 508A table 29.1 is another list, but it strangely doesn't mention anything about grouping. I guess the UL table is the best choice, but it seems strange that I could put a bunch of power wire in one duct and not have to worry about heating (something that the NEC seems to pay close attention to). Seems like such a basic question, but I'm struggling to find a satisfying answer. Share this post Link to post Share on other sites
Posted 25 Mar 2011 Gamble - I see that this post is about 4 months old... I hope the answer still finds you. I would refer to Article 378 for Non Metallic Wireways. The NEC General Provisions for Wiring Methods in Article 300.1(A) state that method for all wiring installations are covered by Article 300. However, 300.1(B) refers to UL 508 and the NFPA 79 for control equipment or listed utilization equipment. Now, the NFPA 79 allows non metallic ducts for internal wiring, but doesn't give tables for raceway fill... [79]1.5 does state that if specific provisions are not made in the publication [79], then refer to the provisions of the NEC [70]. If you look at the definition for Non Metallic Wireway in [70]378.1, it fits the bill. JMK Share this post Link to post Share on other sites
Posted 17 Aug 2011 In a wireway the NEC does not require derating for control conductors if they operate at <10% of their ampacity. What does UL 508A say? Share this post Link to post Share on other sites
Posted 18 Apr 2012 (edited) http://wiki.xtronics.com/index.php/Wire-Gauge_Ampacity Edited 18 Apr 2012 by Emach Share this post Link to post Share on other sites