Can security guards enter the offices of the building they are meant to be guarding?

its just that i am attempting to answer this law question, and i need to know whether they have access or not. i assume they dont but would like to chekc with anyone who has knowledge of such. i need to know so that i can determine whether such a securty guard could be charged with burgalry when entering the owners office as a tresspasser

Security guards can enter every area of a building they are guarding, unless the contract they are working under specifically restricts them from a certain area. The guard would not be entering the office as a trespasser or committing burglary. Like I said, the contract drawn up by the owner of the building is the most important factor. In my experience, it is rare that security guards are restricted from any areas of an office building.

if they suspect something or have to go to the bathroom then yes

the security guards at my work enter the offices and patrol to ensure everything seems ok.
on weekends they patrol inside the building as well as outside
hope this helps

yes they can it is a part of their job to check All areas of the building

Yes.
Just because you work there doesnt mean you own that office. If the owner of the company wanted he could send security in and have them go through every section of that office, your computer hard-drive, your desk, your locker and everything. Its not yours. You only work there.