The Federal District Court for the Western District of Pennsylvania has held that evidence of a prior criminal conviction can not be used to impeach the credibility of a plaintiff in a civil suit.
Tussel v. Witco Chemical Corp., 555 F. Supp. 979 (W.D. Pa. 1983).
Michael J. Heilman,
Federal Rules of Evidence - Rules 609(A) and 403 - Witnesses - Impeachment by Prior Criminal Conviction,
Duq. L. Rev.
Available at: https://dsc.duq.edu/dlr/vol22/iss2/10