(a) Subject to the provisions of specific proceedings, any person may file a petition to intervene. The petition shall set forth the grounds for the intervention, the position and interest of the petitioner in the proceeding, the extent to which the petitioner desires to participate in the proceedings, and the name, mailing address, e-mail address, and telephone number of the petitioner.

(b) A petition for intervention shall be filed no later than the deadline established by the presiding member, or if none is established, at least 30 days before the first evidentiary hearing in the proceeding. If the time period between notice of the first evidentiary hearing and the hearing is less than 30 days, the notice shall set a deadline for intervention of at least 10 days from the date of the notice.

(c) The presiding member may grant intervention and may impose reasonable conditions on an intervenor's participation, including, but not limited to, ordering intervenors with substantially similar interests to consolidate their participation or limiting an intervenor's participation to specific topics. An intervenor is a party to a proceeding.

(d) The presiding member may grant late petitions only on a showing of good cause by the petitioner. No person who becomes a party shall be permitted to reopen matters or reopen discovery dealt with in the proceeding prior to the time when such person became a party, without an order from the presiding member based upon a showing of good cause.

(e) Any ruling on a petition to intervene may be appealed by the petitioner, to the commission within 10 days of the ruling. Failure to file a timely appeal will result in the presiding member's ruling becoming the final action on the matter.

(f) Any petitioner may withdraw from any proceeding by filing a notice to such effect.