There seems a misconception from many of the posters here that community eruvin today are “more kosher” than they were in Europe 100 years ago. While it may be true many mitzvos we do today are more mehudar than back in Europe (tefilin, 4 minim on sukkos etc.) from what I have read it seems the opposite is true for eruvin. From the seforim I have read it seems that most community eruvin rely on several heterim. While most people would turn down an esrog if you would tell them “some poskim would be matir it but R Moshe holds it’s posul”, it is odd that the same people have no problem if you tell them “If you want to carry here there are some poskim you can rely on but R’ Moshe would hold you are chayav skila”
YFR Bachur even went as so far to say “asides we have the cahzon ish….” Do you the Chazon Ish who said he has never seen a pasul mikva and a Kasher eruv”? Huh the Chazon Ish was on the exact opposite side of this discussion.
Let’s get real here and discuss some tachlis issues
A) Definition of reshus Harabbim deoraisa
B) Sechuris from a municipality
C) Crooked poles
D) Poles not directly under the wire
E) Drooping wires
F) Body of water within the eruv
G) The Rambam on how much can you rely on tzyras hapesach
H) Karpef in the eruv and what qualfies as a karpef
I) When using gud asik is it enough to eyeball it or do we need a plumbline?
J) Using tachuv for a tzuras hapesach
k) Obstructions between the vertical pole and the horizontal pole/string
L) using a tapoered pole
M) slanted wires (not completely parallel to the ground)
This is a start. Answer some of these then can the makilim please come back to join the discussion.
Also to be addressed is the “stacking of kulos”. Let’s say an eruv relies on a heter from Gadol A for issue number 3 but Gadol A is machmir on issue # 7 so they rely on Gadol B for that. For issue #6 Gadaol B is machmir so they rely on Gadol C. That means that it is possible if you were to ask any of the godelim you rely on, they would ALL pasul for one reason or other.