The staff of the Commission will not be examined either by interrogatory or deposition except when leave to undertake the examination is granted by the Commission, a motions commissioner, or a motions examiner upon petition alleging that one of the following exists:

1. (1) The staff person has direct personal knowledge of evidence relevant to the proceeding other than evidence gathered as a result of investigation.
2. (2) For other reasons which shall be set forth with particularity, justice requires that the petition be granted.
3. (3) Discovery has revealed that the staff person will be called as a witness.

Source

The provisions of this § 42.57 adopted April 19, 1991, effective April 20, 1991, 21 Pa.B. 1909.