The key interlock provision enables the user to mount a one- to four-cylinder, narrow faced, Kirk-type FN or Superior customer-supplied lock on the face of the breaker. This accessory provides mounting for key interlocks that are furnished by the customer. The key interlock provision works in conjunction with the padlock provision. The key interlock extends through the padlock hasp when the key is turned to the key removal or bolt extended position. Additionally, the accessory provides a hasp for mounting three padlocks with 1/4" to 3/8" diameter shanks.