Double Compensation

Hi! Please help me understand this issue about double compensation. When it is lawful and it is unlawful? I am a government employee now, last two years I was connected in a private school as a faculty. I resigned because of my transfer to my current employment. However, just this few weeks the school requested me if I could teach as part time after my office work (probably 5:30 pm down, MWF) since I have my job 5-12,1-5pm Full time. My questions are 1- if I will accept the offer, is it legal? Because my office mate told me that it can be considered as double compensation. 2- I have known many of the faculty teaching in that school as Part time while Full time employee in government offices also but unlike me they are CPAs, does it considered them as exempted in double compensation law, while me as MBA graduate (no license) will not? Please guide me. I really wanted to know the legality of this issue. Thanks ahead!

If you work full time then your teaching load will be after that time (5PM).

How many hours would that be?

Would you have enough rest to do your full time job after your other work as a teacher?

At any rate, it may be best to ask the your department head, the appropriate HR/Admin Department or the CSC directly for further clarification.