I just purchased the calculations DVD set and I've come across an issue I'm failing to understand. That issue relates to sizing conductors for continuous loads. On page 246 of the Electrical NEC Exam Preparation text book under the heading "Overcurrent Protection of Conductors" there is a question asking me to size a conductor for a 104A continuous load. The 104A load is then multiplied by 125% to arrive at 130A for a 1 THHN conductor on 75 degree terminals.
This all makes perfect sense accept for the fact that table 310.16 states in its title the following: Allowable ampacities of Insulated Conductors...
According to article 100, the definition of ampacity is stated as follows: The current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature rating.
So, my question is this; Why am I increasing the ampacity of a conductor for continuous loading if table 310.16 already takes continuous loading into account?
Richard Lee
This all makes perfect sense accept for the fact that table 310.16 states in its title the following: Allowable ampacities of Insulated Conductors...
According to article 100, the definition of ampacity is stated as follows: The current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature rating.
So, my question is this; Why am I increasing the ampacity of a conductor for continuous loading if table 310.16 already takes continuous loading into account?
Richard Lee