# DC wire round-trip drop; constant temperature and resistivity
length = 5 m in 1..20 "One-way run"
current = 10 A in 1..30
area = 2.5 mm^2 in 1..10
resistivity = 0.0175 ohm*mm^2/m "Illustrative copper"
roundTripResistance := 2 * length * resistivity / area [ohm]
drop := current * roundTripResistance [V]
check voltage drop: drop <= 1 V
scenario long run: length = 12 m