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Real Life Eruv by Naomi Cohen

L’ilui nishmat Pesach Nachman ben Tzvi Hirsh (Peter Olswang)


I was responsible for building our suburban Eruv (London) a few years ago, but it was only as I started to learn Masechet Eruvin that I understood what an Eruv actually represents:

Daf 3a – “: קִדְרָא דְבֵי שׁוּתָּפֵי, לָא חַמִּימָא וְלָא קָרִירָא.” “As people say: A pot belonging to partners is neither hot nor cold. When responsibility falls upon more than one person, each relies on the other, and ultimately the task is not completed.” 

An Eruv is the responsibility of all the people that live within it and wish to use it on Shabbat. This is contrasted with a Succah which is personal property. The people might be members of more than one shul or of none; but essentially the establishment of the Eruv brings them together as an entity. And the sole purpose of that entity is to be jointly responsible for the Eruv itself! 


In 2013, I supervised the construction of the Woodside Park Eruv. Woodside Park is a small community in north London, around 5 miles/8 km from the main Jewish areas of Hendon, Golders Green and Edgware. Those areas built their eruvim in the early 2000s after many years of campaigning for permission from the local authority, Barnet Council. 

London Eruv

Our team had already spent several years identifying a route that would use existing boundaries as much as possible – particularly the fencing alongside railway lines and highways. Planning permission was required from the local council, as they are effectively the landowners of the roads and sidewalks, and this was a slow frustrating process. It was also necessary to draft licence agreements with the council and the railway companies to accept long-term responsibility for the poles on their property, and to fundraise for some significant licence fees and legal costs as well as the actual construction. Unlike Israel and US, it’s not feasible to use utility poles. 


As voluntary project manager, I oversaw the contract and supervised the works, but my most important job was explaining the concept of an Eruv to non-Jewish landowners. We had to ask permission to measure their front garden walls, come on their land to inspect their rear garden boundaries and, on a couple of occasions, put up temporary or permanent fencing to fill in gaps. I generally found their responses to be warm and positive… I hope that I would also be as accommodating for another faith’s seemingly irrational requests!


I started learning Daf Yomi this January, encouraged by Rabbi Daniel Epstein. I found a daily podcast, Talking Talmud by Anne Gordon & Yardaena Osband, which discussed the most interesting point of each day’s daf in accessible language and a friendly, encouraging style that encouraged me to open a Gemara and read it by myself for the first time.  


It quickly became clear that Masechet Eruvin is not an instruction manual for building an Eruv! It dives right into tiny details without defining terms or even explaining the concepts. Particular case studies are discussed in huge detail, when it seems likely that they only existed to test us like a tricky exam question. As I often heard on Talking Talmud, the Rabbis seem to assume that you are completely familiar with the whole Gemara before starting the first daf. 


These are some of the main concepts which were relevant to the construction of our Eruv: 


Lavud was very useful during construction. For a standard tzurat hapesach of posts and wire, it was crucial to put the post close enough to the front garden wall. It was very convenient that my hand span is 22 cm, a bit less than 3 tefachim, so that was the unit of measurement for any gap that we wanted to check. It’s about the smallest gap a child could fit through, so it seems reasonable that any gap this size in a wall wouldn’t count if it couldn’t become an access route for people. Similarly, you couldn’t squeeze between a post and a wall if they are closer than 3 tefachim.


Gud asek mechitza, which literally means extending the walls upwards, allows the Eruv boundary to ‘jump’ vertically from a bridge to the road below it (using a lechi). In one case, we had a problem where the stretch of pavement nearest to the house wall had utility cables and couldn’t be dug up. How could we reach from the tzurat hapesach pole to the house to complete the road junction?  Our inventive contractors fixed a 2m-long arm to the top of the 6m-high pole. This carried the wire across the pavement to line up with the post next to the garden wall. We hung a weight from the end of the arm to confirm that the post was exactly underneath it. On this occasion, 3 tefachim wasn’t good enough… every millimeter counted.


Another issue was the fencing of allotments (community gardens) as these were considered to be in the category of karmelit. Our suburban eruv covered an area of approximately 36 square kilometers and included 17 allotments and cemeteries! Luckily they were mostly fully fenced but there was one which had no effective boundary along much of its 2 km length. 


I had to convince the allotment committee to allow us to install chicken wire or agricultural fencing, which they were concerned would restrict the movement of wildlife into and out of the allotment. They agreed this but only on the condition that in some areas, we could build a ‘living fence’ out of branches. So, 30 members of the community spent a Sunday morning clearing vegetation and helping to make the hedge. During lockdown, I have often walked past it, and I love the fact that the Eruv gave us the opportunity to build something tangible and long-lasting as well as the relationship with our non-Jewish neighbours. 


Another allotment needed fencing for a stretch of its boundary along a brook, so I got to know the head of the committee while we agreed the exact location for the fence. I also met his brother who has beehives on the site, as he had to puff smoke over the bees to calm them the day before we installed the fence! I came back before Rosh Hashanah to buy some honey from the hives.


This is England so of course the welfare of animals took priority. The council were concerned that bats and birds might be damaged or even decapitated by the very fine fishing wire, so in a couple of locations we were required to use wire of 10 mm diameter. We tried a marine rope and a steel cable, but it inevitably sagged across a span of 30 meters, no matter how tight we tried to pull it. The Beth Din ruled that it was not halachically valid, as the sag was more than 3 tefachim (the limit using lavud), which was a significant problem. Once the planning inspector had visited, a line of fishing wire “appeared” above the sagging cable – this was installed as the effective eruv, and the cable underneath it would deter any flying wildlife from getting too close. 


So, perhaps the practicalities of building an Eruv are not so different from learning the Gemara after all. We had to work hard to accommodate all the diverse opinions that were expressed by the different parties, and found ourselves experts on the minutiae of the law, which it was assumed we already knew. After all the ups and downs, licenses and permits, poles and wires, we succeeded in building a community project that binds everyone together to enjoy Shabbat.


Responsibility for the Eruv continues – a team of Shomerim check the wires early every Friday morning and we have a very obliging contractor who is available for fixing any issues as a high priority, especially in the winter.
However, about once a month I am called to sort out a pruning issue, with my 3-m long secateurs. eruv fig trA tricky situation occurred in September, when a branch of an overhanging fig tree had got tangled in the wire. This week, we are looking at alternative options for a footpath where the wire has been broken several times over the past few months.
I still don’t take the Eruv for granted – the community has benefitted hugely from the removal of restrictions on pushing and carrying, but every Friday morning as I turn on my phone, I am grateful that it hasn’t been too frosty or windy, and we won’t have a last-minute panic before the all-important text is sent pinging around the community to tell them all is well for another Shabbat.



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