935. Transferring an Object Left in a Courtyard When Shabbos Began

Eiruvin 3:19

If an object was left in a courtyard when Shabbos began, it is permitted to transfer it to a roof or to the top of a wall regardless of whether the residents of the courtyards made an eiruv for themselves or not. After transferring the object to a roof, it may be moved another roof even if that second roof is higher or lower than the first. It may then be taken from the second roof to another courtyard, and from there to a third roof in yet another courtyard. From there, it may be taken to an alley, and then to a fourth roof. One may carry throughout an entire city by way of courtyards and roofs, or enclosed areas and roofs, or courtyards and enclosed areas, or any combination of the three. One may not, however, bring the object into a house unless the residents of all these different domains make a single eiruv among them.

Eiruvin 3:20

On the other hand, if some item was inside a house when Shabbos began and it was only later brought out to a courtyard, it may not be moved to a different courtyard, to another courtyard’s roof, to the top of a wall or to an enclosed area unless the residents of all the areas in question join together in a common eiruv.