694. An Eiruv May Not Be Made on Shabbos

95:15 One may not place eiruvei techumin on Shabbos or on yom tov. (Even after the fact, such an eiruv would not be effective – Mishnah Brurah 416:20.) Therefore, if a yom tov falls on Friday and a person wants to go somewhere on Shabbos, he must place the eiruv before yom tov. Similarly, if a yom tov begins after Shabbos and one wants to go somewhere on yom tov, he must place his eiruv on Friday. The law of one who establishes his “home base” by walking there is discussed in Shulchan Aruch Orach Chaim 409:7. The rules regarding a yom tov that falls on either side of Shabbos or for the second day of a yom tov outside of Israel, if one wants to make an eiruv for one day in one direction and for the second day in the other direction, are discussed in chapter 416.

95:16
A person’s property and his animals are like his feet; he may not, for example, lead his animals to a place where he himself may not go. (If an animal wishes to leave the Shabbos boundary on its own, the owner need not stop it – MB 305:77. Conversely, one may not lead an animal outside of its Shabbos boundary even if the one doing the leading remains within his own – Shaarei Tziyon 305:73.) If one lent or rented his items to another person, or gave them to someone to watch for him, then they are like the feet of the one who currently has them in his possession, even if he is a non-Jew. The animals and property acquire their “home base” for Shabbos at his place. The property of non-Jews also acquire a “home base” for Shabbos in the place where they are at twilight.