Q. Re- question 4276 you stated that If one made an Eruv Tavshilin, the purpose is to provide the permission to do a usually prohibited work in Yom Tov for Shabbos when needed. It fulfills it’s purpose whether one used it or not, so the bracha recited on it will not normally be an unnecessary blessing, and he is not obligated to do some Melacha (work) on Friday to avoid a Bracha L’vatala (an unnecessary blessing for the Eruv).

So why did Maran Rosh Yeshiva Zt’l insist that he needed to do melacha to avoid bracha levatala as was reported?

A. Moadim Uzmanim (7; 122) rules that even if one already did everything needed for Shabbos before Yom Tov began, one should still do and Eruv Tavshilin with a brocho.

However, Igrois Moshe (O.H. 5: 20) indeed disagrees and rules that if one is certain that he has done everything for Shabbos before Yom Tov, one should not recite a brocho before placing the Eruv.

In reality, most often people have to do something for on Yom Tov Erev Shabbos, so unless one is totally certain that nothing is needed the brocho should be said.

As we wrote: “the brocho recited on it will not normally be an unnecessary blessing.” even according the Igrois Moshe.

Horav Shlomo Miller’s Shlit’a opinion is similar.

Horav Aharon Miller Shlit’a added, that since one should wash before Shabbos begins his face, hands and feet, and that is done with hot water, there is normally a melacha done, and the brocho should be recited

Rabbi A. Bartfeld as revised by Horav Shlomo Miller, Horav Dovid Pam, Horav Aharon Miller and Horav Chanoch Ehrentreu Shlit’a