On a film set, this title is for the first assistant to the head electrician
The term 
Best Boy refers to the best electrician in the team led by the gaffer (chief lighting 
... Boom Operators assist the production sound mixer on film and television sets, 
and... [DOC] [TLE] Hollywood Hard Hats - Forbes [PAR] Mar 2, 2006 ... A guide to nonacting jobs on movie sets.