[If the cabinet] is standing in the doorway, open to the outside, [and there is] tumah inside [the cabinet], the house remains tahor. [If there is] tumah in the house, what-ever is inside [the cabinet] becomes tamei, because it is the way of the tumah to exit, but it is not the way [of the tumah] to enter. If its wheel extends [no more than] three fingerbreadths beyond [the basket], [and the wheel contains] tumah that is beneath the ceiling beams [of a house], the house remains tahor. When does this ruling apply? When (1) there is a space of one [cubic] handbreadth [in the wheel], (2) [the wheel] is not removable, and (3) the cabinet is large.