A secondary disconnect assembly is for an electrical switching apparatus, such as a power circuit breaker. The secondary disconnect assembly includes a terminal block mount having a number of first mounting features, at least one terminal block, and at least one accessory plug. Each terminal block includes a number of receptacles and a number of second mounting features, which cooperate with the first mounting features to properly align, mount and stabilize the terminal block on the terminal block mount. Each accessory plug includes a number of contact alignment features structured to align and guide the accessory plug into a corresponding one of the receptacles.