Halacha for Tuesday 1 Tammuz 5780 June 23 2020

Question: May one set an alarm clock to go off on Shabbat?

Answer: It would seem to be prohibited to set an alarm clock to go off on Shabbat based on the Baraita (Shabbat 18a) which states, “One may not place wheat into a water-operated mill (before Shabbat) in order for the wheat to be ground on Shabbat.” Although no forbidden work is being performed on Shabbat as the wheat is being placed in the mill before the onset of Shabbat and it will only be ground on Shabbat as a result of the water’s movement, nevertheless, since the mill produces noise on Shabbat, this constitutes a disrespect for the Shabbat. The Sages of the Talmud disagree whether or not the Halacha follows the opinion of this Baraita. Some conform this Baraita to all opinions and it will therefore be forbidden to begin any forbidden work before the onset of Shabbat if it will continue on Shabbat and produce noise. Others explain that this Baraita is contingent upon another related disagreement between Bet Shammai and Bet Hillel such that according to Bet Hillel, there is no concern with such noise being produced on Shabbat and it will be permissible to place wheat into a mill before Shabbat in order for it to be ground on Shabbat itself.

Halachically speaking, Maran Ha’Shulchan Aruch (Chapter 252) rules that “It is permissible to place wheat into a water mill shortly before the onset of Shabbat and we are not concerned that as a result of the noise, people will say that so-and-so’s mill operates on Shabbat.” The Rama, on the other hand, rules: “Some rule stringently regarding a mill and anything else which produces noise. We are indeed preferably concerned with this view; however, in situations of financial loss, there is room for leniency.”

Based on the above, regarding our situation, it seems that according to the Rama that one may not cause noise to be produced on Shabbat, it will likewise be forbidden to set an alarm clock to go off on Shabbat, for this constitutes a disrespect for the Shabbat as it seems that one is operating the alarm clock on Shabbat and causing noise to emanate. According to this, it will be forbidden for Ashkenazim to set an alarm clock to go off on Shabbat.

Indeed, Hagaon Harav Moshe Feinstein zt”l rules likewise in his Responsa Igrot Moshe (Orach Chaim, Volume 4, Chapter 70) and writes that Ashkenazim, who follow the rulings of the Rama, may not set an alarm clock to go off on Shabbat if it can be heard outside of the room it is located in. (However, if the volume of the alarm clock is not so strong and can only be heard within the room it is located in, even Harav Feinstein rules leniently.) We see that Hagaon Feinstein equates the law of an alarm clock to a vessel which produces noise on Shabbat.

Nevertheless, Maran Rabbeinu Ovadia Yosef zt”l (in a response printed in Yalkut Yosef, Shabbat, Part 1, page 89) quotes several Acharonim who rule that there is room for leniency in this regard, even according to the Rama’s opinion, for according to all opinions, if the noise is not heard immediately after the action the individual performs, such as regarding a mill, and is only heard later, there is no prohibition of producing noise here. Additionally, most people do not set their alarm clocks to go off every day; rather, it is already set to wake them up at the same time every day. If this is the case, there is certainly no room to prohibit setting an alarm clock for Shabbat, for the Poskim (quoted by the Bet Yosef in Chapter 338) that it is permissible before Shabbat to set a clock to go off and make noise every hour of Shabbat since everyone knows that such a clock is set once and no one sets it every day. The Rama himself quotes this as Halacha.

Thus, halachically speaking, it is permissible for both Sephardic and Ashkenazi Jews to set alarm clock before the onset of Shabbat to go off on Shabbat. Hagaon Harav Eliezer Yehuda Waldenberg zt”l and other great Poskim rule likewise.

Ask the Rabbi


8 Halachot Most Popular

The Laws of Glassware and Pyrex Regarding the Prohibition of Milk and Meat Mixtures-Continued

In the previous Halacha we have written that according to Maran Ha’Shulchan Aruch, glassware does not absorb any flavor from foods placed in it and thus, there is no prohibition to use a glass vessel for meat and then after it is washed well, to use it for dairy (although the Rama does rule st......

Read Halacha

Question: Must one designate two different sets of glassware for dairy and meat as one would with other utensils?

Question: Must one designate two different sets of glassware for dairy and meat as one would with other utensils? Answer: We have already established in the previous Halacha that one is obligated to designate two separate sets of dishes and flatware for dairy and meat, for dishes used with either......

Read Halacha

The “Shehecheyanu” Blessing on a New Garment

Question: When is the appropriate time to recite the “Shehecheyanu” blessing on a new garment, at the time of purchase or the first time one wears it? Similarly, must one recite this blessing for every new piece of clothing one purchases? Answer: The Mishnah (Berachot 54a) teaches us ......

Read Halacha

The Laws of Milk and Meat Dishes and the Laws of Giving Putrid Taste

When one cooks meat in a pot, the walls of the pot absorb some of the food cooked in it and is therefore considered “meat”. If dairy is later cooked in the same pot, the pot will release some of the meat flavor contained in its walls into the dairy food and will therefore prohibit the en......

Read Halacha


Reciting the “Shehecheyanu” Blessing on Similar Types of Fruit

In the previous Halacha, we have established that one should recite the “Shehecheyanu” blessing on citrus fruits, such as grapefruits or oranges, which are not so readily available throughout the year. When one merits eating from these fruits the first time during the year and the fruits......

Read Halacha

Reciting the “Shehecheyanu” Blessing on Grafted Fruits

Question: May one recite the “Shehecheyanu” blessing the first time during the year one eats citrus fruits, such as grapefruits or oranges? Answer: We must first preface this discussion with the law that when one eats a new fruit that one has not yet partaken of that year, after recit......

Read Halacha

The Prohibition of Milk and Meat Mixtures

The Torah states three separate times (Shemot 23 and 34; Devarim 14): “You shall not cook a kid in its mother’s milk.” Our Sages (Chullin 114a) expounded that each of the times this prohibition is mentioned comes to teach us another law: The first time it is mentioned teaches us ab......

Read Halacha

The “Three Weeks”

The three-week period between the Seventeenth of Tammuz and the Ninth of Av is dubbed by our Sages “Between the Straits,” based on the verse (Eicha 1, 3), “All of her enemies overtook her between the straits.” Our Sages tell us that these three weeks between the Seventeenth o......

Read Halacha