We use the word eiruv in various contexts: Maseches Eruvin, Hilchos Eruvin, Eiruv Chatzeiros, Eiruv Techumin, Eiruv Tavshilin, and more.
The literal translation of the word eiruv is “mixing.” Onkelos, in his translation of the verse “lo sizra karm’cha kilayim,” translates the word kilayim as eiruvin.
In Eiruv Chatzeiros, all the residents of the courtyard are “mixed” together.
In Eiruvei Techumin, the boundary of the city and the boundary of the place where the eiruv is placed are “mixed” together.
In Eiruv Tavshilin, the dishes for Yom Tov and the Shabbos that follows are “mixed” together.
There is mixing and confusion of concepts in everything related to the term eiruv.
A news article once appeared with the headline: “All IDF bases were enclosed with Eiruv Chatzeiros.” The free translation of that headline would mean that all the bases were enclosed with bread or matzos (see the entry Eiruv Chatzeiros).
Or someone may ask about the eruv wire: “Is this the Shabbos boundary?” The answer is no — the eruv wire is not the Shabbos boundary. The Shabbos boundary is approximately one kilometer beyond the wire (see the entry Eiruv Techumin).
The network of wires we call an “eiruv” is a borrowed term and does not appear in the Gemara or in halachah. It does not “mix” anything, and it would be more accurate to call it “the city partitions,” or something similar.
A mechitzah teluyah is a partition that is raised three tefachim (24 cm) or more above the ground. Since a goat can pass beneath it, the partition is not considered a valid enclosure, and one does not apply to it the rule of gud achis (“extend and lower”).
Eruvin are generally constructed from both tzuras hapesach and from partitions, fences, buildings, etc. To determine the validity of the partitions, we must ensure that all fences are either flush with the ground or raised less than three tefachim (24 cm) above it. Therefore, one should not evaluate fences from a distance with a rough estimate, but must examine the bottom of the fence up close. This problem is very common in eruvin. Even in areas with security fences or military bases, suspended partitions have been found due to animals or erosion.
Additionally, there are cases in which a partition invalidates a tzuras hapesach, and in order to validate the eruv, one may intentionally invalidate the partition by cutting the bottom of the fence so that it becomes a mechitzah teluyah, instead of dismantling the entire structure.
There are three or four conditions required to define an area as a reshus harabbim on a Torah level. The conditions are:
The source for these conditions is the Camp of Israel in the wilderness.
To permit carrying in a reshus harabbim, a tzuras hapesach is ineffective; only doors that are locked at night, as existed in Jerusalem in earlier times, are valid.
Where does this apply to us?
Today, the overwhelming majority of eruv boundaries are constructed from tzuras hapesach. There are eruvin within which run roads that may be considered reshus harabbim, such as Highway 4 (Geha), Route 40, Route 90, Ayalon, the Coastal Highway, and others. If these roads are classified as reshus harabbim, the entire eruv becomes invalid. Therefore, when planning an eruv, it is advisable—whenever possible—to exclude major highways from within the eruv boundary. When this is not feasible, expert consultation is required.
A tzuras hapesach is a halachic partition considered a full enclosure in every respect. The reasoning behind this form of closure is that in every enclosed area there are openings that allow entry and exit. There is no limit to how many openings may be made in an enclosed structure; some houses have one opening, and some have many openings.
The structure of a tzuras hapesach consists of three parts, each with its own halachos:
The vast majority of contemporary eruvin are built from tzuras hapesach. The poles serve as the doorposts, and the eruv wire serves as the lintel. It is sufficient to learn the halachos of tzuras hapesach in order to inspect the poles and wires of the various eruvin and evaluate their validityIt is appropriate to mention the view of the Rambam, who holds that one cannot enclose an entire area solely with tzuras hapesach; rather, at least 50% of the perimeter must consist of actual partitions, and only the remainder may be closed with tzuras hapesach. His reasoning may be that we do not find a house made entirely of openings, and only when a significant portion is solid may one add many openings. The Shulchan Aruch cites the Rambam’s view as a yeish omrim, and the Mishnah Berurah writes that one should be stringent like his opinion.
In large eruvin it is not feasible to be stringent like the Rambam, and almost all eruvin are lenient against his view, except in neighborhood eruvin and in communities or bases enclosed by a fence.
The Gemara mentions several times a chatzer and a rechavah and the distinction between them. Both a chatzer and a rechavah are areas adjacent to the dwelling and enclosed by partitions. A chatzer is a front courtyard used for various daily activities, such as laundry and similar uses. A rechavah is a rear courtyard used for long-term storage and is considered a place without residents, similar to a storage area or shelter today.
Where does this apply to us?Today, some homes have a front courtyard, but in most buildings the area closest to the entrance of the home is the stairwell. The poskim disagree whether such areas have the same status as courtyards of earlier times (regarding eiruv chatzeiros, lighting Chanukah candles, and more), or whether their status is different.According to the Chazon Ish, our courtyards do not have the halachic status of a chatzer, since we do not use them for residential functions but rather for leisure or aesthetics. As a side note, for this reason (among others) we do not permit contemporary streets with a lechi or korah, as described in the Mishnah at the beginning of the tractate. The definition of a mavoi is an alleyway with two courtyards, and in each courtyard two houses – and since we no longer have courtyards like those of the past, a mavoi also lacks the required conditions to permit it with a lechi or korah
A courtyard in the past –
A courtyard today –
