QO Load Centers offer premium features like QO breakers, ground arc fault interrupters and surge arresters. QO load centers are designed for residential and industrial use to protect electrical systems, equipment and people. Systems are single or three phase and have indoor and outdoor versions. QO Load Centers enable the use of a full complement of accessories. Indoor enclosures are designed to be rotated 180 degrees to accommodate top or bottom service entrance feed. This handle padlock attachment is for padlocking 100A to 225A main circuit breaker in a convertible load center in the OFF position.