Abstract: An improved bus plug door interlock for use with a bus plug in conjunction with an electrical power busway distribution system is described. The bus plug includes the bus plug door interlock, a door, a housing and an electrical switch. The bus plug door interlock prevents the bus plug door from opening when the electrical switch is in the "on" position and prevents the power from being turned "on" when the door is open. The bus plug door interlock includes a door interlock pivot with a single flat surface and a elongated slot with a narrow and a wide section. When the door interlock pivot is in the narrow section of the elongated, the single flat surface engages narrow section of the elongated, preventing the electrical switch from being turned "on". When the door interlock pivot is in the wide section of the elongated slot, the door interlock pivot can rotate freely, allowing the electrical switch to be turned "on".