A circuit breaker includes an enclosure with a first side and a second side opposite and distal from the first side. A number of separable contacts are enclosed by the enclosure. An operating mechanism is structured to open and close the separable contacts. A plurality of terminals are electrically interconnected with the number of separable contacts. The terminals protrude through the second side of the enclosure. A number of phase barrier apparatus is disposed on the second side of the enclosure. Each of the number of phase barrier apparatus includes a plurality of separate phase barrier members, each of which is disposed about a corresponding one of the terminals, and a number of interlocking members. Each of the number of interlocking members interlocks with an adjacent pair of the separate phase barrier members.