I have paid into SS my entire career (38 yrs) and will be able to collect at 66.6 yrs of age. I am currently 59 and have changed careers and am contemplating working for the school district which means I will be not contributing to SS but will instead put into a Cal Pers account. So my question is will my SS be affected by taking a job and working for the next 7yrs under Cal Pers.
Your Social Security retirement benefit rate could be affected by a Cal PERS pension, but not if you've had 30 years of what Social Security considers to be 'substantial' Social Security covered earnings. The substantial earnings amount for each calendar year is listed on the following Social Security publication: https://www.ssa.gov/pubs/EN-05-10045.pdf.
If you become entitled to spousal, divorce spousal, widow's or surviving divorced spouse's benefits, those benefits could be reduced if you receive a Cal PERS pension. For more information on this provision, refer to this publication: https://www.ssa.gov/pubs/EN-05-10007.pdf.