[RE-wrenches] Parallel Wire combining

[Larry]

Wrenches,

If I combine 3 conductors of equal length in parallel, is the resulting 
size equal to 3 times the Circular Mil area? For example, #4 is 42,080cm 
so are three #4's close to 2/0 (134,200cm) in size? Is it as simple as 
this? Assuming the conductors can not be removed individually, does this 
mean the current capacity is equal to the resulting wire size?

Thanks, Larry