Good luck with that unless California AB 465 passes and is signed by governor Brown and upheld in federal court. (Note: There is some concern AB 465 might not survive a federal court challenge as it might conflict with the Federal Arbitration Act).
Most employers make binding arbitration a necessary condition of employment. Binding arbitration makes it almost impossible to win a case against an employer.
Binding arbitration is not so binding especially in cases that violate federal law related to the EEOC or NLRB. I am in the middle of writing a post about this. Will share when done.
That's because HR literally exists to protect the company from you. You don't report serious issues to HR. You hire a lawyer.