Mike your answer is corrct assuming this is 600V or less we are talking about.
Ghost you seem to have the Arc Flash and Shock boundaries confused.
Greg, well put.
LAB may only be crossed by Qualified Personel (As defined in the 70E). RAB requires shock protection, usually just means gloves but can be more. PAB should be treated as the boundary you never cross but special training and hazard analysis would allow crossing. Shock boundaries only apply if there are exposed live parts.
Neither of these have anything to do with the arc flash boundary, the shock boundaries are dependant on voltage, the flash boundary has nothing to do with voltage levels, it is based on available fault current and clearing time of the protective device. PPE for flash protection must be worn any time you cross the Arc Flash boundary and "interact" with the equipment, weather the live parts are exposed or covered.