29 – Eruvin

01. Transforming a Public Domain

As we learned in chapter 21, one may transport items on Shabbat within a private domain (reshut ha-yaĥid) but not more than four amot within a public domain (reshut ha-rabim) and not from a public to a private domain and vice versa.

An eruv, however, transforms a reshut ha-rabim into a reshut ha-yaĥid, thus allowing people to transport items within that area without limit, as well as to transport items from homes and yards into that area, and vice versa.

An eruv has two components, one pertaining to the area that will be transformed into a private domain, and the other relating to the people who will live within the eruv’s boundaries. In order to define the area as a single private domain, it must be enclosed by a fence. However, this is not enough. The people who live within the area must also establish a partnership with one another. This is done by means of two meals worth of food that is owned collectively by everyone and from which anyone may partake. This communal food is called an eruv (literally “merging”) because it merges or joins together all the homes and yards, turning them into a single private domain. Nevertheless, it has become commonplace to call the enclosure itself an eruv as well, and we follow this convention.

As we learned (21:2-3), there is a difference between a reshut ha-rabim by Torah law and a semipublic domain (karmelit), which is treated as a reshut ha-rabim by rabbinic law. In order to permit carrying in a reshut ha-rabim by Torah law, the area must be enclosed by a wall or fence at least ten tefaĥim high (approximately one meter),[1] and the gates that people use to enter the enclosure must be locked at night (SA 364:2).

However, a karmelit, considered a public domain on the rabbinic level, need not be enclosed by an actual fence. Rather, it is sufficient to surround it with tzurot ha-petaĥ (defined in the following section) to transform it into a reshut ha-yaĥid (SA 362:10-11).


[1]. A tefaĥ, according to R. Ĥayim Naeh, is eight cm. Ten tefaĥim, then, is 80 cm. He bases his calculations on Rambam’s opinion regarding the size of a dirhem (a unit of mass derived from the Greek drachma coin). However, it has since been ascertained that a dirhem at the time of Rambam was more than ten percent smaller in volume than the Turkish dirhem with which R. Naeh was familiar. This means that R. Naeh’s shi’ur is too large. Using the corrected measurements, a tefaĥ is 7.6 cm and ten tefaĥim is 76 cm. Ĥazon Ish, basing himself on Noda Bi-Yehuda, maintains that a tefaĥ is 9.6 cm. The law accords with Rambam, whose opinion is accepted by the vast majority of poskim, taking into account the current knowledge about the size of the dirhem. Nevertheless, for two generations, people have grown accustomed to relying on R. Naeh’s shi’ur. Additionally, some follow the stringent opinion of Ĥazon Ish. It would seem reasonable le-khatĥila to follow Ĥazon Ish when building an eruv (whether enclosed by a fence or tzurot ha-petaĥ), since sometimes the wire droops. When that happens, if the eruv was constructed based on a small shi’ur, its validity is uncertain. By following Ĥazon Ish, we avoid this problem. In addition, an eruv is meant to serve the entire community. Le-khatĥila, when acting on behalf of the entire community, it is more important than usual to try to meet the requirements of all the different opinions. In light of all this, I write generally that ten tefaĥim is approximately one meter (following Ĥazon Ish), even though technically one could follow the smaller, updated shi’ur. When there is a gap of ten amot, which can disqualify the eruv, one should be stringent and use the smaller, updated shi’ur of 4.56 m.

02. Tzurat Ha-petaĥ

We have learned (21:8-9) that according to most poskim, today’s streets are considered a karmelit. Thus, to permit carrying in the streets, it is sufficient to surround them with structures resembling doorways (tzurot ha-petaĥ), which form a kind of wall around them.

The basic form of a doorway is comprised of two doorposts with a lintel atop them. A lintel can be formed by laying a board across the top of two posts or running a string above the posts.

The main requirement for a tzurat ha-petaĥ is for the posts on the sides and the string or wire above them to be configured like a doorway. Since the lowest doorway is ten tefaĥim high, the poles of a tzurat ha-petaĥ must be at least that high to be considered valid for an eruv. The wire extended above them must also be at least ten tefaĥim above the ground. Accordingly, if any part of the wire droops lower than that, the entire area between the poles is considered breached, since there is no actual doorway in which any part of the lintel is lower than ten tefaĥim. And if the poles are more than ten amot (4.56 m) away from one another, the entire eruv is disqualified, as a breach of ten amot disqualifies an eruv.

Since the poles form the sides of the tzurat ha-petaĥ, they must be strong enough that a normal wind would not cause them to sway, and to support some type of door, even if only an extremely light one made of straw (SA 362:11).[2]

According to most poskim, there is no limit to how wide a tzurat petaĥ may be, as it can retain the basic form of a doorway even if it extends for a thousand amot. However, Rambam maintains that when most of the eruv’s perimeter is comprised of tzurot ha-petaĥ, no tzurat ha-petaĥ may extend longer than ten amot. Le-khatĥila, when possible, his opinion should be taken into consideration. However, in practice, since it is very difficult to enclose towns and cities using tzurot he-petaĥ that are limited to ten amot, we are lenient and do not limit the width of a tzurat petaĥ (SA 362:10).

The wire that is stretched between the tops of the poles must be secured well enough that it will not become detached in a normal wind. Le-khatĥila, when possible, it should be stretched taut so that it will not even sway in the wind or droop down below the tops of the posts, since lintels do not normally sway or droop. However, be-di’avad, even if the wire sways or droops, the eruv is kosher (MB 362:65; AHS 362:37).


[2]. The pole that is used to form the tzurat ha-petaĥ must look like a pole. Therefore, one should not use a wall as a pole for this purpose (MA 363:28). However, if the tzurat ha-petaĥ is parallel to a wall and continues where the wall leaves off, the edge of the wall can be considered a pole (Ĥazon Ish 70:15; see R. Elimelech Lange, Hilkhot Eruvin 4:12, p. 55).

03. Ensuring That the Wire Is Stretched Across the Tops of the Posts and Electrical Poles

One must take care that the wire that serves as the lintel stretches over the poles, not alongside them, as in a tzurat ha-petaĥ the lintel sits atop the doorposts. Even if the post is low and the wire runs far above its tip (as with power lines), as long as the wire runs directly over the post, and the post is at least ten tefaĥim high, it is considered a valid doorpost, and the wire is considered a valid lintel. But if the wire is not directly above the pole, the eruv is invalid. If the pole is crooked, the wire must extend directly above the tip of the pole; if the wire is above any other part of the pole, the eruv is invalid (SA 362:11; MB ad loc. 64).[3]

Utility poles and the cables they support cannot serve as tzurot ha-petaĥ, because the cables generally do not pass directly over the poles, but alongside. In order to solve this problem, additional poles, each about a meter high, must be erected directly underneath the cables.[4]


[3]. When erecting a low pole underneath a wire that extends high above, one must ensure that there is nothing between the poles and the wire, such as an awning. This is the position of Taz and MB 363:112. However, some are lenient be-di’avad, including AHS 363:46 and Meshiv Davar 1:26.

If a pole has a hole near the top, according to most poskim one can thread the wire through it. The wire is not considered situated on the side of the pole, since it is still situated above the section of the pole below it. Even though the pole continues above the wire, this is not a problem. This is the approach of AHS 362:32 and Ĥazon Ish 7:9. However, Pri Megadim and MB 362:64 are stringent. Since the pole continues above the wire, the wire cannot be considered situated above the pole. The same disagreement applies to a pole that has deep grooves, where the wire is wrapped around them in such a way that it is contained completely within the grooves. Those who are lenient consider the wire situated above the pole, while those who are stringent maintain that since the pole continues above the wire, the wire cannot be considered situated above the pole. In a time of necessity, one may rely on those who are lenient.

[4]. When several utility poles are situated in a straight line, it is enough to erect eruv posts underneath the cables of the two outlying utility poles. The poles in the middle are not considered doorposts, but only extra supports for the lintel. This is the opinion of most poskim, including Divrei Malkiel 3:16. Nevertheless, some are stringent and require placing an eruv pole underneath every single utility pole, because otherwise those who see them may mistakenly think that utility poles never need to be supplemented with eruv poles.

What I have written concerning utility poles is the opinion of the vast majority of poskim. A lenient opinion maintains that only if one constructs a tzurat ha-petaĥ but attaches the wire to the side of the poles does he show that he is not interested in constructing a valid tzurat ha-petaĥ. In contrast, if poles are erected for a different purpose, such as in the case of utility poles, and wires are attached to the sides of these poles, this does not show that one is not interested in a tzurat ha-petaĥ. Therefore, this opinion allows these poles to be used for an eruv (Sho’el U-meshiv, Mahadura Kama 2:88). Some are lenient because the settings over which electrical wires pass are tightly connected to the utility pole and are considered part of it, so the wires are above the pole in accordance with the lenient opinion in the previous note. Furthermore, according to some, Rif and Rambam maintain that even if the wire is situated at the side of the pole, this does not invalidate the eruv. This opinion is quoted in Ĥelkat Yaakov 1:200. In practice, we do not use utility poles for tzurot ha-petaĥ without first making the adjustments described above. See R. Elimelech Lange, Hilkhot Eruvin ch. 4 nn. 60, 66, and 67.

04. Fences, Breaches, and a Tel Ha-mitlaket

A fence that is ten tefaĥim high is considered a bona fide wall and is effective in transforming even a reshut ha-rabim by Torah law into a reshut ha-yaĥid (as explained above in 21:2-3). Even a chain-link fence is acceptable for this purpose. As long as each of the spaces between the wires is less than three tefaĥim wide, the fence is considered continuous, and it can transform even a reshut ha-rabim by Torah law into a reshut ha-yaĥid.

If a fence or series of tzurot ha-petaĥ encloses an area but has gaps in the perimeter, as long as each gap is less than ten amot wide and the combined width of all the gaps on any side of the perimeter is less than the combined length of the fence or tzurot ha-petaĥ on that side, the eruv is kosher (MB 362:45; however, AHS 362:23 maintains that the lengths to compare are those of the entire perimeter, not just one side). In contrast, if the unfenced section of any side of the city is longer than the fenced section on that side, or if there is a gap anywhere that is longer than ten amot, the eruv is invalid (SA 362:9).

If one side of the city consists of houses with yards enclosed by fences, with open space between the yards, then if the distance between each yard is less than ten amot, and the width of each yard is greater than ten amot, there is no need to enclose that side any further with a wall or tzurat ha-petaĥ. The fences surrounding the yards are considered walls, and the gaps of less than ten amot do not disqualify them.

If a city is encircled by a garden with terraces at least ten tefaĥim high, then it is considered walled, and there is no need to add another wall or tzurat ha-petaĥ. If only part of the city is enclosed by a terrace, then that part needs no additional wall.

If one side of a city is built on a hill, then if the hill is steep enough that it declines ten tefaĥim (76 cm) every four horizontal amot (1.824 m), it renders everything above the slope a reshut ha-yaĥid. The Sages refer to such a hill as a tel ha-mitlaket, and it is considered a bona fide wall (SA 345:2).

If a town is surrounded by a fence, and the gate at the entrance road is wider than ten amot, then as long as the gate will be closed at night, the eruv is valid even when the gate is open (SA 364:2; Melumdei Milĥama §74). However, if the gate is generally left open at night, or if it merely serves as a barrier (or boom gate), which, even when closed, is not a proper wall, a tzurat ha-petaĥ should be erected above the gate.

05. Forming a Partnership Using Two Meals’ Worth of Food

As we have seen (section 1 above), in order to transform a reshut ha-rabim or karmelit into a reshut ha-yaĥid in which carrying is permitted, it is not enough to enclose it in a fence or tzurat ha-petaĥ. A partnership must also be formed among all the residents in the enclosed area. This is accomplished by means of bread owned jointly by every resident of the enclosed area. It is not necessary to use bread made from one of the five species of cereal grains; rice bread is also acceptable (SA 366:8). If fewer than eighteen people live in the enclosed area, it is sufficient to have enough jointly-owned bread for each person to have the volume of one grogeret (dried fig). If there are exactly eighteen people, a volume of eighteen grogarot is required, the quantity considered the equivalent of two meals’ worth. For a group of more than eighteen residents – even a thousand – the amount of bread required to form a partnership between all of them does not change, but remains uniform at two meals’ worth.

The poskim disagree about the precise quantity of two meals’ worth of food. The accepted ruling is that le-khatĥila the volume of eight eggs (about 400 ml) should be used, while be-di’avad the volume of six eggs (about 300 ml) is sufficient (SA 368:3). As mentioned above, this communal food is called an eruv (literally “merging”) because through it everyone is merged or joined together, and their enclosed property is defined as a reshut ha-yaĥid.

Since the eruv bread belongs to all residents of the city, any of them may eat it whenever he wishes. If the eruv was eaten during Shabbat, the residents may continue to carry for all of that Shabbat. Since the eruv was there during bein ha-shmashot on Friday (when Shabbat began), the partnership was already formed. For the next Shabbat, however, a new eruv must be set aside.[5]

On a kibbutz or anywhere else where all the residents eat together in a communal dining hall, it is sufficient to erect a tzurat ha-petaĥ around the area. It is not necessary to put aside two meals’ worth of food in such a case, since the food in the communal kitchen serves to form the general partnership necessary for an eruv.


[5]. There are actually two types of “eruv” that transform a public domain into a private domain: eruv ĥatzerot (“merging of courtyards”) and shitufei mevo’ot (“sharing of alleyways”). The purpose of an eruv ĥatzerot is to permit carrying in a reshut ha-yaĥid that is divided into areas owned by different people. The Sages decreed that one should not carry from a home belonging to one person to a home belonging to another, even when both homes are a private domains. Since they belong to different people, the area between them resembles a public domain. By setting aside an eruv ĥatzerot, the homeowners become partners, and may carry from one home to another. The food for an eruv ĥatzerot must be placed in one of the homes (SA 368:3), and it must consist of bread (SA 368:1). In contrast, a shitufei mevo’ot is more effective, because it transforms all the homes, yards, and streets into one domain, within which everyone may carry. Therefore, the food for a shitufei mevo’ot does not need to be placed in a home; a yard can suffice. It also does not have to consist of bread; two meals’ worth of any food is acceptable. When a shitufei mevo’ot is set aside, there is no need for an eruv ĥatzerot. This is why nowadays the custom is to leave the eruv food in the synagogue; even though it cannot be considered a home, the eruv is valid, because it is in fact a shitufei mevo’ot (SA 368:3; 386:1 and BHL ad loc.). Nevertheless, since a shitufei mevo’ot can also serve as an eruv ĥatzerot, we make sure to use bread.

06. Setting Aside the Eruv and Reciting Its Berakha

It is customary to use matza for the eruv, as it has a long shelf life and can continue to serve as the eruv for as long as it remains edible (SA 368:5). Common practice is to set aside a new eruv before Pesaĥ each year and to recite the berakha and the formula for setting aside the eruv of the upcoming year (detailed below). In many communities, the rabbi is given the honor of performing this ritual on behalf of the community. Even if the residents forgot to set aside a new eruv before Pesaĥ, as long as the old eruv is still in existence, one may continue carrying throughout the enclosed area.

The eruv must be placed in one box or bag. The custom is to leave it in the synagogue or nearby, as the synagogue is a communal space.

Before setting aside the eruv, one must make sure that it belongs to all residents of the city. Therefore, the person charged with setting aside the eruv first lifts the matzot one tefaĥ with the intent to acquire them on behalf of all the city’s residents. In order for him to acquire the matzot successfully, they must have previously belonged to a different person.

Before acquiring the eruv and setting it aside, the following berakha must be recited: “Blessed are You, Lord our God, King of the universe, Who sanctified us with His mitzvot and commanded us concerning the mitzva of eruv” (“asher kideshanu be-mitzvotav ve-tzivanu al mitzvat eruv”). Afterward, he should recite:

With this eruv it shall be permitted to us (all the people living here in the town, city, or courtyard) to bring things in and out – from the houses to the yard and the yard to the houses, from house to house, from yard to yard, from roof to roof, from houses and yards to alleyways, and from alleyways to houses and yards in this city – for us, all who live here, and whoever joins us during all upcoming Shabbatot and holidays. (SA 365:15; MB ad loc. 83)

07. An Eruv Where Shabbat Desecrators Live

The eruv, the two meals’ worth of food that all residents within the enclosed area own jointly, unites all the residents and renders the enclosed area a private domain, where carrying is permitted. However, all this is on condition that all the area residents, without exception, are partners in the eruv. If any one of them is not interested in participating, then the area can no longer be considered a single domain, and the eruv is invalid.

In light of this, it is problematic to implement an eruv in cities and towns whose residents include Jews who do not observe Shabbat. Since they are not interested in an eruv, they and their homes are not included in the partnership of the eruv, which means the eruv cannot be valid. The same problem exists if a non-Jew lives in the area; since his home is not included in the eruv, the eruv is invalidated (SA 385:3; 382:1).

The solution is for the Shabbat desecrator or non-Jew to rent out his home for Shabbat to one of the Shabbat observers. This way his home will be included in the eruv as well. The problem with this solution is that it is almost impossible to implement in large towns, let alone cities. Therefore, it became customary to use a different solution – renting all the homes in the area from a city official who has the authority to enter every house in the city (SA 391:1).

Some argue that this solution is not viable today. In a democratic country, the mayor of a city does not have the right to enter the home of a private individual without a warrant. Still, the custom is to be lenient. After all, during wartime, the town major and the head of home front command may requisition homes of their choosing. They may even do so during training exercises. Therefore, these authorities have a share of ownership in all the homes, and one may rent their share from them before Shabbat for the purposes of the eruv.[6]


[6]. In Israel, a local rabbi generally acquires ownership from the mayor, as well as from the chief of police. Some also do so from the director of the local branch of the Ministry of the Interior, since in an emergency the police chief is authorized to enter any home, while the mayor and the representative of the Ministry of the Interior have authority over the streets. The terms of the acquisition grant the rabbi permission to leave things wherever he wants, making him a part owner of all places within the enclosed area. As a result, the eruv can include everyone in the area.

It should be noted that we always tend to be lenient regarding the issue of constructing an eruv in a place where Shabbat desecrators live. This is because the prohibition on including non-Jews or Shabbat-desecrating Jews in an eruv is really a punitive stringency; technically, they may join with Shabbat-observing Jews to form an eruv partnership. The Sages wanted to discourage observant Jews from living in neighborhoods with Shabbat desecrators and non-Jews, so they penalized those who did so by forbidding such an eruv. However, if there is no alternative, we make use of any reasonable justification to be lenient and participate with all local residents in making an eruv. See Ĥazon Ish 18:9; AHS 391:4; Menuĥat Ahava vol. 3, p. 363.

08. An Eruv That Becomes Invalidated on Shabbat

Sometimes it becomes apparent during Shabbat that a wire from the eruv has snapped in a certain place, thus invalidating the eruv. Two questions then arise: 1) May the eruv be fixed on Shabbat? 2) If it turns out that the eruv cannot be fixed, do all the residents need to be informed that the eruv is down so they know not to carry?

Le-khatĥila, if a non-Jew is available, it is preferable that he fix the eruv. Although asking a non-Jew to do melakha for Jews on Shabbat is rabbinically prohibited, nevertheless, when there is a great need to save the masses from the prohibition of carrying on Shabbat, the Sages permitted asking a non-Jew to fix the eruv, even if this will involve melakhot that are prohibited by Torah law (MB 276:25; above 9:12).

However, if no non-Jew is available, a Jew certainly may not violate Torah prohibitions in order to fix the eruv. For example, if a pole has fallen over, a Jew may not stand it back up by jamming it into the ground. Similarly, if the wire has snapped, one may not tie it back together with a permanent knot, as tying this type of knot on Shabbat is forbidden by Torah law. However, the poskim debate whether one may tie a bow knot (the type used to tie shoelaces), as tying this type of knot on Shabbat is permissible.

Some argue that fixing the eruv on Shabbat is absolutely forbidden. Even though it is permissible to tie a bow knot on Shabbat, nevertheless in this case tying it would permit carrying on Shabbat. This means that by tying it, one constructs a meĥitza ha-materet (above, 15:4), which is forbidden on Shabbat. In other words, the Sages prohibited making a wall that serves to permit something that was previously halakhically forbidden. In this case, before one tied the knot it was prohibited to carry, while afterward it was permitted.

Others maintain that although the Sages generally forbade constructing a meĥitza ha-materet, nevertheless, in order to save the masses from sinning by carrying on Shabbat, one may create a meĥitza ha-materet by tying a bow knot. This is the common custom (Responsa Mahari Ashkenazi §13; Panim Me’irot 1:30; Sho’el U-meshiv, Mahadura Tinyana 1:89; SSK 17:34).

If the eruv cannot be fixed, this should not be announced publicly. This information is withheld out of concern that some people will carry anyway, desecrating Shabbat knowingly, and it is better that they transgress unknowingly rather than knowingly. The only people who should be informed are those who will definitely follow the halakha and refrain from carrying.[7]


[7]. This is the approach of Maĥshavot Be-etza §16. In principle, whenever there is a chance that people will listen, even if it is more likely that they will not, we do not say that “it is better that people transgress unknowingly rather than knowingly.” As long as there is a chance that they will listen to reproof, we must reprove them (MB 608:3 based on Rosh). Accordingly, it would seem at first glance that the public must be informed that the eruv is down, as there is a chance that many people will follow the halakha and refrain from carrying. Nevertheless, R. Shlomo Zalman Auerbach explains (SSK ch. 17 n. 139) that carrying unknowingly in this case is considered even less severe than transgressing unknowingly in general; since people believe the eruv is still valid, as far as they know they are carrying permissibly. Thus, one who carries in such a situation is viewed as transgressing a rabbinic prohibition obliviously (mitasek). Therefore, it is better not to announce that the eruv is down.

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