Gaps of Different Sizes - Eruvin 8b

Eruvin 8b: Gaps of Different Sizes

(excerpted from The Contemporary Eruv)

An unrectified gap that is wider than ten amos invalidates an enclosure - even if the rest of the eruv is omed merubeh al ha'parutz. If a gap that wide exists in an eruv, it must be rectified by a tzuras ha'pesach. [Shulchan Aruch, ibid., 362:9. See the Mishna Berura there, 362:52. The Chazon Ish (Orach Chaim 107:5) holds that me’d'oraysa, omed merubeh al ha'parutz overrides a gap even if it is greater than ten amos. The Igros Moshe, ibid., 5:28:3 rejects this Chazon Ish, and holds that the breaks of more than ten amos invalidate the enclosure even me’d'oraysa (if they are not rectified by tzuras ha'pesach). Reb Moshe’s reasoning here is unclear. See the attempt by the editors of this, the latest volume of the Igros Moshe, there to clarify the issue.]

A gap that is narrower than ten amos may also invalidate an enclosure - if it takes up an entire side (i.e., direction, north, south, east or west) of the eruv - unless the gap is on the fourth side of the eruv, in which case, as we have seen (Chapter I, Section 3), posts or beams suffice. [Shulchan Aruch, ibid., 363:1. See also Bi’ur Halacha 362:8, d.h. Parutz Merubeh and Nesivos Shabbos 14:6 and note 13.]