18 CFR §154.210

1. (a)Unless the notice issued by the Commission provides otherwise, any protest, intervention or comment to a tariff filing made pursuant to this part must be filed in accordance with § 385.211 of this chapter, not later than 12 days after the subject tariff filing. A protest must state the basis for the objection. A protest will be considered by the Commission in determining the appropriate action to be taken, but will not serve to make the protestant a party to the proceeding. A person wishing to become a party to the proceeding must file a motion to intervene.
2. (b)Any motion to intervene must be filed not later than 12 days after the subject tariff filing in accordance with § 385.214 of this chapter.