By Rabbi Yehonason Sassportas
Given the fact that bungalow colonies are generally surrounded by an Eruv, we present a general outline of the factors that may cause this enclosure to become invalid, so that even a layman may identify them.
An Eruv, which comprises of many posts upon which a string passes, is referred to in halacha as a tzuras hapesach, the frame of a doorway. That is, instead of creating an actual partition, we may affix two side-posts with a crossbeam or string upon them in a fashion that resembles a doorway, and this serves as an equally valid partition. If many such doorways are joined together to enclose an area, carrying on Shabbos is permitted within the entire area – provided that an Eruv Chatzeros is also in place. That is, bread or matzah was gathered on behalf of all the area’s inhabitants and is placed in one of the dwellings.
Since, as mentioned, an eruv made of posts upon which a string is placed is essentially many “doorways” joined together, the nature of the placement of the eruv must also resemble a doorway, in the following manner:
A) The side-posts must be at least 10 tefachim (approximately 40 in.) high, and strong enough to support a door made of straw1. Also, they must be firmly attached so that they do not sway in the wind.
B) Similarly to the lintel of a doorway, the string must be placed directly above the side-posts2. Therefore, care should be taken to ensure that the nail which holds the string does not bend outward, as this may cause the string not to be directly above the side-posts. Also, one should ensure that the string is not deflected from a straight line above the posts by the branches of a tree or any other object.
C) Likewise, the string should be made as taut as possible. Otherwise, it may sway in the wind and thereby not be directly above the side-posts. Also, it may sag downwards to the point that it no longer resembles the lintel of a doorway3.
D) Preferably, the side-posts should be equal in height, so that the string above them is placed horizontally, like the lintel of a doorway. However, if they are not equal in height they are nevertheless valid, as long as the disparity between them doesn’t cause the string to be placed at an extreme angle, i.e., more than 45 degrees4. Some maintain that this concern applies only when the side-posts have intrinsically different heights, but not where one is higher than the other only because they are placed on different levels of a hill5.
E) Some add that a similar concern applies where the tzuras hapesach doesn’t resemble a doorway because the side-posts are standing on a tilt, despite the fact that the string is placed horizontally6. Therefore, after a windstorm, one must ascertain that the side-posts were not knocked over in a manner that they stand on an angle. In case of need, however, one may rely on the many opinions who consider even a tilted side-post to be similar to a doorway7. However, they should not bend at an extreme angle.
F) Since the area between two side-posts is considered a doorway, it may not be obstructed in a way that does not leave a clear opening four tefachim(approx. 16 inches) wide. Therefore, care must be taken that bushes do not obstruct the entranceway between two side-posts.
In a similar vein, one of the side-posts may not be situated within an enclosure. Because the additional partition causes a separation between two side-posts and prevents them from acting together in creating a symbolic “doorway”8. Therefore, care should be taken when adding fences to a yard that they do not entirely enclose one of the side-posts.
It is proper to check the Eruv every Friday, to ascertain its validity for Shabbos use. Once it has been checked it may be used the entire Shabboswithout concern. However, if a storm has possibly rendered it invalid, it must be checked once again before being used9. Should the eruv be found to have been rendered invalid, it may no longer be used on that Shabbos10, with the exception of the following scenarios:
1) If the string ripped in only one place and the rest of the enclosure is intact, and the two side-posts between which the string ripped are less than 10amos apart11.
2) If the side-posts are intact but the string ripped, a gentile may be asked to attach the strings together in a way that is only rabbinically prohibited12.
3) In cases where the invalidity of the Eruv does not result from the unanimous consensus of all halachic authorities, there may be additional room for leniency. Therefore, where an Eruv is irreparable on Shabbos, a Rav should be consulted whether it can nevertheless continue to be used until it can be fixed after Shabbos.
1 Eruvin 11b, Shulchan Aruch 362:11
2 Shulchan Aruch ibid., Rosh to Eruvin 11a
3 Teshuvos Mishkenos Yaakov 111, Chazon Ish, Eruvin 71:10. Cf. Machatzis Hashekel 362:21
4 Rabbi Akiva Eiger to Shulchan Aruch ibid., see Mishnah Berurah 362:60 and Sha’ar Hatziyun. See also Bris Avraham O.C. 16:5, and Avnei Nezer O.C. 297
5 Machsheves Yisrael, Tikunei Eruvin 17
6 Chochmas Shlomo 362:11
7 See Sefer Tikun Eruvin pp. 41-44
8 Avnei Nezer O.C. 291, see also Divrei Malkiel 3:17, and Zekan Aharon 1 O.C. 19, for additional reasons why this invalidates the eruv, see Mekor Chaim, Tikun Eruvin
9 See Teshuvos Har Hakarmel O.C. 18
10 Shulchan Aruch 365:7
11 Teshuvos Har Hakarmel ibid.
12 Teshuvos Panim Meiros 1:30