A shutter assembly for a switchgear cabinet, comprising: a shutter moveable along a bus bar or bus bar extension of a power bus, the shutter for covering access to the bus bar or bus bar extension, in a disconnected position for a circuit breaker, the bus bar or bus bar extension having an insulator cap covering a free end thereof, the shutter allowing access to the bus bar or bus bar extension in a connected position for the circuit breaker, the connected position being when a connector assembly of the circuit breaker is connected to the bus bar or bus bar extension, the movable shutter including a spring biased support, the moveable shutter having an opening through which the bus bar or bus bar extension passes, the shutter being slideable along the bus bar or bus bar extension away from the insulator cap, in response to a force applied by a leading edge of the connector assembly when in the connected position, and the shutter being slideable along the bus bar or bus bar extension toward the insulator cap, in response to a force applied by the spring biased support, when the circuit breaker is moved into the disconnected position, the insulator cap fitting closely within the opening in the shutter, to thereby prevent access to the bus bar or bus bar extension when the circuit breaker is in the disconnected position. a shutter moveable along a bus bar or bus bar extension of a power bus, the shutter for covering access to the bus bar or bus bar extension, in a disconnected position for a circuit breaker, the bus bar or bus bar extension having an insulator cap covering a free end thereof, the shutter allowing access to the bus bar or bus bar extension in a connected position for the circuit breaker, the connected position being when a connector assembly of the circuit breaker is connected to the bus bar or bus bar extension, the movable shutter including a spring biased support, the moveable shutter having an opening through which the bus bar or bus bar extension passes, the shutter being slideable along the bus bar or bus bar extension away from the insulator cap, in response to a force applied by a leading edge of the connector assembly when in the connected position, and the shutter being slideable along the bus bar or bus bar extension toward the insulator cap, in response to a force applied by the spring biased support, when the circuit breaker is moved into the disconnected position, the insulator cap fitting closely within the opening in the shutter, to thereby prevent access to the bus bar or bus bar extension when the circuit breaker is in the disconnected position. a spring biased support, the moveable shutter having an opening through which the bus bar or bus bar extension passes, the shutter being slideable along the bus bar or bus bar extension away from the insulator cap, in response to a force applied by a leading edge of the connector assembly when in the connected position, and the shutter being slideable along the bus bar or bus bar extension toward the insulator cap, in response to a force applied by the spring biased support, when the circuit breaker is moved into the disconnected position, the insulator cap fitting closely within the opening in the shutter, to thereby prevent access to the bus bar or bus bar extension when the circuit breaker is in the disconnected position.