Conductors (both copper and aluminum) are typically categorized in American Wire Guage (AWG), except when aluminum is used on a 200-amp circuit it is categorized as #250 MCM. What does MCM stand for? :-k
MCM Thousand Circular Mils (Wire Gauge)
Now that is kcmil in the code books
Excellent! Thanks to you both. I found lots of references to kcmil but couldn’t find MCM. Much appreciated.