General rules
Primary source
Verbatim text below is from the Electronic Code of Federal Regulations (eCFR), a public-domain U.S. government work. Always verify the current version with the eCFR before relying on it for any legal matter.
Full Text
(a) An individual who becomes covered by FERS as a result of an election under § 846.201 is subject to the provisions of chapter 84 of title 5, United States Code and parts 841 through 845 of this chapter, except as provided in this part.
(b) Civilian service performed before the effective date of the election under § 846.201 is not creditable under FERS except as provided in this part.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.