What parameters does a CA employer have on dictating when an employee may use accured vacation time? When I reqested to take one of my 5 accrued vacation days off, my employer informed me that it is their policy that employees must use their entire 5 days vacation consecutively, all at one time. There is nothing in the employee handbook or employee policies and procedures book regarding this, and I was never informed of this policy prior to asking for the one day off. Is thier policy legal?

Unless CA once again has a law different than the other 49 states, yes, it is. There is no law that an employer has to provide you with vacation at all; they get to decide the limits under which it can be used.

Nor does it have to be in the employee handbook to be a policy that can be enforced, although it's obvious that, in this particular situation, this is a major component of the policy and it really should be there for the employee's information, if nothing else.