So the wording leaves the rationale irreproachable? How is having [SDS] control conductors in the same conduit going to reduce the amount of I˛R heat, compared to a similar scenario where the control conductors are run separately? That is, conduit run with control conductors and more than three motor circuit conductors requires no derating, versus a conduit run just with more than three motor circuit conductors does require derating...? I must say, that's defies the logic and purpose of derating.
Originally Posted by don_resqcapt19
Now you have me wondering how 110.14(C) terminal temperature limitations applies to Article 430 motor circuit conductor ampacity. Chapter 2 continuous load conductors must also have an ampacity of 125% of the calculated load current... but we are permitted to use the conductor ampacity rating before adjustment and correction, i.e. the higher temperature Table value (e.g. 90°C rating) [210.19(A)(1)]. There is no such clause in Article 430 (that I'm aware of). Are we permitted to determine 125% rating from the higher temperature-rating value? If so, where is that stated in Article 430. If not stated anywhere, the 125% ampacity seems to have to be based on the termination temperature limitation ampacity...??????
Last edited by Smart $; 07-17-12 at 04:46 AM.
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