What is the specific law that allows me to carry a firearm inside my own business?
Criminal Defense Attorney
California Penal Code 12031 generally prohibits carrying a loaded firearm in a public place.
However, subsection (h) states: Nothing in this section shall prevent any person engaged in any lawful business, including a nonprofit organization, or any officer, employee, or agent authorized by that person for lawful purposes connected with that business, from having a loaded firearm within the person's place of business, or any person in lawful possession of private property from having a loaded firearm on that property."
Also see Penal Code section 12026.