An interlock system for an enclosure can include a power switch movable between an OFF position and an ON position with a defeater arm coupled to the power switch. The defeater arm can be selectively movable between a locked position and an unlocked position and when the defeater arm is in the locked position the power switch is prevented from moving from the OFF position to the ON position. An interlock can include a pivot bracket pivotally supported by a support bracket within the interior of the enclosure and movable between a first orientation, in which the pivot bracket is out of engagement with the defeater arm, and a second orientation, in which the pivot bracket displaces the defeater arm into the unlocked position. When the door is moved into a closed position from an open position, a door bracket displaces the pivot bracket into the second orientation.