Example 3 The annual load duration curve of a certain power station can be considered as a straight line from 20 MW to 4 MW. To meet this load, three turbine-generator units, tv rated at 10 MW each and one rated at 5 MW are installed. Determine (i) installed capacity ( plant factor (iii) units generated per annum (iy) load factor and (v) utilization factor.

The wording that I am running into with questions such as "The number of conductors required to be installed between three-way and four-way switches is " is confusing.  The text is not expalining this in a way that I am understanding anything other than grounding conductor, which is optional unless I am using a metal box.  So what type of "conductor" is beng discussed?