5 CFR §734.406

1. (a)An employee covered under this subpart may not participate in political activities:
   1. (1)While he or she is on duty;
   2. (2)While he or she is wearing a uniform, badge, or insignia that identifies the employing agency or instrumentality or the position of the employee;
   3. (3)While he or she is in any room or building occupied in the discharge of official duties by an individual employed or holding office in the Government of the United States or any agency or instrumentality thereof; or
   4. (4)While using a Government-owned or leased vehicle or while using a privately owned vehicle in the discharge of official duties.
2. (b)[Reserved]