Minors aged 15 days to 18 years employed in the entertainment industry must have a permit to work, and employers must have a permit to employ. 16-17 age bracket- They can work for 4 hours in a day and 48 hours in a week during school days.The general rule is that the legal working age in California is 14-years-old, but anybody under the age of 18 must have a work permit. For most employers, a minor must be at least 14 years of age to work. Work Permits In California, most minors under the age of 18 must have a permit to work. In general, the legal working age in California is 14 years old. The Department of Safety may issue age certificates to 16 and 17yearolds. They can only work on school holidays or school vacations. 22. When school is not in session, 16 and 17yearolds may work up to eight hours per day and 48 hours per week. For most employers, a minor must be at least 14 years of age to work.