I still get amuzed by the number of electricians I meet on the job that don't realize you can't run seperate phases to the same three phase load in seperate conduits.
I've had to explain the concept of building a "choke" to more guys than I can shake a stick at.
It's almost as bad as the concept of splicing copper to aluminum in a split-bolt without the divider.
Anyone else have anything to add about this?