When figuring VD for outsiding lighting poles not to exceed 3% with long distance. Example 175 watt 120v poles spaced first pole 100ft from power source then 500,1000 and 1750ft to the last pole 20amp circuit. Do you still figure the total amps of all the lights with the farthest lt for the calc. or do you do the calc. for each lt. then average the voltage drop between them for sizing conductor sizes?