I believe that the distinction was first made by the IBEW. They have had, for some time, "Inside Wireman" and "Residential Wireman" classifications.

"Inside Wiremen," if I remember correctly, is what most of us think of when we say "electrician." There is a 5 year apprenticeship.

"Residential Wiremen" is a 3 year apprenticeship, and has a lower pay scale.

And .. for those who ask ... "Outside Wireman" was the term for PoCo linemen.