ampacity

[Gamble 0]

What charts do you guys use to determine wire size in wire duct?

[Chris Elston 78]

Panduit http://www.panduit.com/Support/DesignTools/index.htm

[Gamble 0]

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.

[JMK 0]

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

[Scada Tom 0]

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?

[Emach 0]

http://wiki.xtronics.com/index.php/Wire-Gauge_Ampacity Edited 18 Apr 2012 by Emach