29 C.F.R. § 1614.301 : Labor — REGULATIONS RELATING TO LABOR — EQUAL EMPLOYMENT OPPORTUNITY COMMISSION — FEDERAL SECTOR EQUAL EMPLOYMENT OPPORTUNITY — RELATED PROCESSES — Relationship to negotiated grievance procedure

(a) When a person is employed by an agency subject to 5 U.S.C. 7121(d) and is covered by a collective bargaining agreement that permits allegations of discrimination to be raised in a negotiated grievance procedure, a person wishing to file a complaint or a grievance on a matter of alleged employment discrimination must elect to raise the matter under either part 1614 or the negotiated grievance procedure, but not both. An election to proceed under this part is indicated only by the filing of a written complaint; use of the pre-complaint process as described in § 1614.105 does not constitute an election for purposes of this section. An aggrieved employee who files a complaint under this part may not thereafter file a grievance on the same matter. An election to proceed under a negotiated grievance procedure is indicated by the filing of a timely written grievance. An aggrieved employee who files a grievance with an agency whose negotiated agreement permits the acceptance of grievances which allege discrimination may not thereafter file a complaint on the same matter under this part 1614 irrespective of whether the agency has informed the individual of the need to elect or of whether the grievance has raised an issue of discrimination. Any such complaint filed after a grievance has been filed on the same matter shall be dismissed without prejudice to the complainant's right to proceed through the negotiated grievance procedure including the right to appeal to the Commission from a final decision as provided in subpart D of this part. The dismissal of such a complaint shall advise the complainant of the obligation to raise discrimination in the grievance process and of the right to appeal the final grievance decision to the Commission.
(b) When a person is not covered by a collective bargaining agreement that permits allegations of discrimination to be raised in a negotiated grievance procedure, allegations of discrimination shall be processed as complaints under this part.
(c) When a person is employed by an agency not subject to 5 U.S.C 7121(d) and is covered by a negotiated grievance procedure, allegations of discrimination shall be processed as complaints under this part, except that the time limits for processing the complaint contained in § 1614.106 and for appeal to the Commission contained in § 1614.402 may be held in abeyance during processing of a grievance covering the same matter as the complaint if the agency notifies the complainant in writing that the complaint will be held in abeyance pursuant to this section.

29 C.F.R. § 1614.301