(a) Discovery procedures described in §§ 502.142 through 502.147, directed to Commission staff personnel must be permitted and must be governed by the procedures set forth in those sections except as modified by paragraphs (b) and (c) of this section. All notices to take depositions, written interrogatories, requests for production of documents and other things, requests for admissions, and any motions in connection with the foregoing, must be served on the Secretary of the Commission.

(b) The General Counsel must designate an attorney to represent any Commission staff personnel to whom any discovery requests or motions are directed. The attorney so designated must not thereafter participate in the Commission's decision-making process concerning any issue in the proceeding.

(c) Rulings of the presiding officer issued under paragraph (a) of this section must become final rulings of the Commission unless an appeal is filed within 10 days after date of issuance of such rulings or unless the Commission on its own motion reverses, modifies, or stays such rulings within 20 days of their issuance. Replies to appeals may be filed within 10 days. No motion for leave to appeal is necessary in such instances and no ruling of the presiding officer must be effective until 20 days from date of issuance unless the Commission otherwise directs. [Rule 208.]