693. Eiruvei Techumin Must Be for a Mitzvah

95:13 The law is the same when one places his eiruv close to the 2,000 cubits outside the city. When he returns to the city and the 2,000 cubits from his eiruv end at the beginning of the city before his house, it is the opinion of most authorities that he may not even return to his home. (Some authorities are lenient when one’s boundary falls within the city; since he sleeps in the city, they consider the whole city like four cubits to him – Rema 408:1, Mishnah Brurah 498:11.)

95:14 One only prepares eiruvei techumin for the sake of a mitzvah, such as to be able to daven with a minyan, or to meet his teacher or a friend who is returning from a journey, or for a meal of a mitzvah, or to take care of communal needs, or if one is returning from a journey and wants to be able to return to home, and similar such cases (e.g., to attend a bris – MB 415:4). (Once the eiruv has been made, he may use it for any purpose – MB 415:7.)