Final answer:
Spare conductors in a raceway must be counted for conductor fill but are not considered for derating purposes because they do not carry current and do not contribute to heat buildup. Thus., the correct option is B.
Step-by-step explanation:
In addressing the question regarding spare conductors installed in a raceway, it's important to understand both conductor fill and derating. Conductor fill refers to the number of conductors that can be installed within a raceway without exceeding its capacity, for safety and functionality considerations.
However, spare conductors are generally not energized and therefore are typically not considered in the derating process, which is the reduction in the current-carrying capacity of a conductor due to environmental factors such as temperature or conductor bundling. Therefore, the correct answer to the question posed is that spare conductors are required to be counted a.
For conductor fill. They are not counted b.
For derating purposes because they do not carry current and thus do not contribute to the heat buildup that necessitates derating.