Q. If you forget to make an eruv tavshilin, you can rely on the Rav’s, but only once. Could you use a different Rav’s eruv another time or only once per persons and it is not dependant on the Rav?

A. The reason you can rely on the Rov’s eruv tavshilin only once is that the repeater is considered willfully negligent (Mishna Berura 527: 22), so the same would apply if he relies on a different Rov’s eiruv. It is worth mentioning that the rejection of the repeaters eiruv, according to a number of Poiskim is only if it is consecutive. If he was diligent and kept with the eiruv mitzva in between, he will not be penalized the next time he forgets (Kaf Hachaim ibid. 48, Betzel Hachochmo 6:91, Piskey Teshuvos ibid. 8). Another leniency is to be found in Aruch Hashulchan (ibid. 18) who suggests that the penalty does not apply in our busy and hectic contemporary society. On the other side, Mogen Avrohom (ibid. 6) rules that if the neglect was done intentionally you cannot rely even once on the Rov’s eiruv. However, Mishna Berura (ibid.26) quotes many Poiskim that permit depending on the Rov’s eiruv even lechatchila when they always do so (which is unusual today). He rules that one may rely on them after the fact for the sake of Simchas and the enjoyment of Yom Tov.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a