The Use of Electricity on Shabbat and Yom Tov
By: Rabbi Michael Broyde & Rabbi Howard Jachter
Rabbi Broyde - Adjunct Assistant Professor of Law at Brooklyn Law School, Rabbi Jachter - Associate Rabbi of Congregation Beth Judah in Brooklyn
Journal of Halacha & Contemporary Society, No. XXI - Spring 91 - Pesach 5751
The topic of electricity in halacha is unique to our generation since there are no direct precedents in the Talmud or rishonim and the halachic discussion of this topic has been ongoing for less than 100 years. It is only since the technology developed and appliances became electrically powered that many of these questions arose... Over time many works were printed and it has become an established part of rabbinic literature. ("Electricity," Encyclopedia Talmudit 18:642).
The advances of technology have posed practical challenge to decisors throughout the ages. One of the hallmarks of Jewish law is its ability - and desire - to assimilate technological advances into the practices of observant Jews. The application of ancient and venerated principles of halacha to new situations has been, and remains, one of the essential tasks of modern decisors of Jewish law. In the last one hundred years, this task has become considerably more difficult due to the rapid and frequent changes in the state of technology.
This article surveys halacha's response to one of the technological breakthroughs of the last 150 years: the invention of electricity. In particular, it explores halacha's understanding of the use of electricity on Shabbat and Yom Tov within the rubric of prohibited work (melacha).1 The technological revolution caused by the widespread use of electrical appliances has led to great discussion and debate within halachic circles. Thousands of monographs, responsa, and books have been written by halachic authorities in the preceding decades relating to the use of electricity on Shabbat and Yom Tov.2
This article is divided into five sections. The first discusses the basis for the prohibition of turning on or off incandescent lights on Shabbat. The second addresses the use of electricity where no light and heat is produced (e.g., turning on a fan). The third discusses the differences between Shabbat and Yom Tov for purposes of the rules developed in sections one and two. The fourth analyzes various specific appliances in light of the rules developed, and the fifth discusses various issues relating to the use of timers to control appliances on Shabbat and Yom Tov.
I. Incandescent Lights on Shabbat
A. Turning On Incandescent Lights During Shabbat
One of the earliest issues involving electricity found in halachic literature was the permissibility of turning on an incandescent light on Shabbat.3 The overwhelming majority of the decisors maintain (for reasons to be explained) that turning on an incandescent light on Shabbat violated a biblical prohibition.
The Mishnah (Shabbat 41a) rules:
One who heats a metal pot [literally, a boiler] may not pour cold water into it to heat it; however, one may pour water into the pot or a cup in order to temper it.
The Talmud (Shabbat 41a-b) in discussing this mishnah states:
Rav Says this mishnah is only ruling [that it is permitted to pour water into a heated pot] when the water temperature is modified, but if the metal is hardened it is prohibited [to heat the metal]. Samuel says this is permitted even if hardening occurs. [The Talmud replied] if the primary purpose [of heating the metal] is to harden the pot, nobody permits it heating.
So, too, the Talmud (Yevamot 6b) declares:
Rabbi Sheshet rules that the cooking [burning] of a wick [of metal], just like the cooking of spices is prohibited on Shabbat [because of the biblical prohibition to cook on Shabbat].
Rambam codifies these rules (Shabbat 12:1) by recounting:
One who heats a metal bar in order to temper it in water has violated the biblical prohibition of lighting a flame.Ravad immediately disagrees as to the nature of the biblical prohibition and rules that heating a metal bar until it glows is prohibited because of either cooking (as Rambam elsewhere appears to classify it (Shabbat 9:6)) or as ma'keh bepatish, completing a nearly finished process. Both authorities, however, agree that a biblical prohibition is violated when metal is heated until it glows. There is no biblical prohibition violated in generating light per se.
Based on the position of Rambam, which most commentaries accept (see Shaar Hatziun, Orach Chaim 218:1), the overwhelming majority conclude that turning on an electric light on Shabbat - an action which heats a metal filament until it glows - violates the biblical prohibition of lighting a flame.4 Some disagree and, based upon the position of Ravad, maintain that while a biblical prohibition is violated, the prohibition is that of cooking (bishul) and not of lighting a flame.5
Yet a third position is found in the commentaries. These authorities limit the statement of the Talmud and codes - that it is prohibited to heat a metal bar until it glows - to the case where the heating is done in order to affect the metal (in the case of the Rambam, to temper the iron). According to these authorities, there is no biblical prohibition intrinsic in the generation of light and heat; rather, that action is only biblically prohibited when it is intended to affect the metal. The incidental heating of the metal in incandescent lights, however, is an action not intended for its designated purpose (melacha she'einah tzrichah legufah) because when one turns on a light one does not intend to affect the metal in the filament. Thus no biblical prohibition occurs. Even the authorities who follow this position concede, however, that a rabbinic prohibition is violated.6
This third position has been categorically rejected by most decisors.7 In fact, in Teshuvot Doveiv Meisharim (1:87), Rabbi Weidenfeld states that the position of those who rule that turning on lights is only a rabbinic violation should not even be taken into consideration by decisors when rendering halachic decisions regarding matters of electricity. Rabbi David Tzvi Hoffman (Melamed Lehoil 1:49) states what has emerged as the consensus opinion: the verse (Exodus 35:3) "One may not create a fire on Shabbat in all your dwellings" describes the prohibition against creating fire of any sort. Current flowing through a filament and causing it to glow creates fire despite the absence of a "flame" and regardless of whether that which is on fire is consumed.8 Rambam's assertion (Shabbat 12:1) that heating a metal is prohibited because of burning only proves this rule, and was not intended to limit it.
The consensus of opinion - accepted by nearly all rabbinic authorities - is that turning on an incandescent electric light on Shabbat violates a biblical prohibition, although the precise prohibition is in dispute; most authorities maintain the prohibition is lighting a flame, and a minority contends that the prohibition is either cooking or ma'keh bepatish.
B. Raising Intensity of an Incandescent Light
Raising the intensity of a light produced by an already glowing incandescent bulb on Shabbat contains issues distinct from that of turning on the light, and in fact a number of modern authorities appear to label this as only a rabbinic violation. Assuming that the prohibition in turning on a light is cooking (bishul), as the Ravad and others maintain, it is possible that raising the heat and light output of the light is analogous to reheating an item which is already cooked. The glowing light is similar to the cooked food. If that is correct, then raising the light intensity is not a biblical prohibition just as reheating an already cooked food is not a biblical violation (Minchat Shlomo pp. 109-110). The Chazon Ish disagrees (Orach Chaim 50:9) and states that since the additional heating increases the light production, it is not analogous to reheating a cooked item, and a biblical prohibition is violated.
According to those authorities who locate the prohibition in turning on a light in burning, as most do, every increase in intensity would logically seem to be an additional violation.9
C. Turning off or Dimming Incandescent Lights
As was first pointed out by R. David Tzvi Hoffman (Melamed LeHoil, Orach Chaim 49) and widely accepted since, the turning off or dimming of an incandescent light on Shabbat is considered to be only a rabbinic violation.10 This is because according to biblical law (deorayta) the only time an action is prohibited on Shabbat is when the prohibited work is done for its direct consequences (melacha she-tzrichah legufah) and that the prohibited result must occur. For example, if one were to pour water onto another's field intending only to dispose of water - and not to irrigate the crops (the intended purpose of the biblical prohibition of watering a field) - although the actions are physically identical to a prohibited biblical action, the intent of the person (to wash his hands rather than irrigate the field) spares one from a biblical violation.11
The Talmud (Shabbat 44a, 42a, 134a) states that extinguishing a flame is biblically prohibited only when the person who is doing the extinguishing desires the product of the extinguished flame (e.g., ashes (carbon black) or dirt) and not when one "merely" intends to remove the flame and have darkeness.12 In all other instances, only a rabbinic violation is committed. Thus, turning off an electric light is certainly no worse than directly extinguishing a lit flame which, if done to create darkness rather than to produce ashes, is only a rabbinic violaton.13
Rabbi Auerbach argues that there is another reason turning off incandescent lights on Shabbat is not a biblical prohibition. He claims that turning off a light by turning off the switch is analogous to removing all the fuel from an oil lamp on Shabbat in manner which does not directly extinguish the flame. If this is so, it would unquestionable be only a rabbinic violation to extinguish a flame on Shabbat.14
D. Non-Incandescent Lights
The use of non-incandescent lights - such as fluorescent15 or neon,16 which do not produce light by heating a strip of metal which glows but rather by electrically exciting gases to emit light - are not prohibited on Shabbat because of the prohibition(s) discussed in this section. Since these lights do not contain a filament that glows, they are halachically identical to an appliance and not a light (and thus will be discussed in part II). There is not generic prohibition to create a light on Shabbat; rather, incandescent lights because of the way they operate happen to violate the prohibition to create a flame. So, too, extinguishing fluorescent "lights" on Shabbat is not rabbinically prohibited as a form of extinguishing since halacha does not recognize that there is a "light" to be turned off.17
The consensus of opinion is that turning on or raising the intensity of an incandescent light is biblically prohibited on Shabbat. Turning off or dimming such a light is rabbinically prohibited on Shabbat. Non-incandescent "lights" are not considered "lights" according to halacha.18
II. Using Electrical Appliances (Other than Lights) During Shabbat
Section one addressed the prohibitions associated with the use of electricity to generate heat and light. This section surveys the halachic issues involved in the use of electricity when there is no apparent generation of (and no intent to create) light and heat. The consensus of halachic opinion maintains that it is typically prohibited to turn on electrical appliances on Shabbat. However, a clear understanding has yet to emerge regarding why such a prohibition exists; indeed, one eminent authority maintains that the use of electrical appliances is only prohibited because of tradition. Seven reasons have been advanced to prohibit the use of electrical appliances on Shabbat.19 The first six reasons are summarized as follows:
1. Turning on an appliance is analogous to creating something new (molid) which is prohibited on Shabbat.
These first six possible bases for prohibiting the use of electrical appliances on Shabbat divide into two groups. The first four relate to the completion of a circuit which causes current to flow.20 the final two locate the source of the prohibition in running (and not turning on) the appliance. If each of these prohibitions were to be found inapplicable, then only the following reason would remain:
7. The use of electricity without light or heat is actually permitted, but because observant Jews since the invention of electricity have maintained that it is prohibited to use electrical appliances on Shabbat, and rabbinic authorities approved of this stricture, it is prohibited to use such appliances - absent great need - because of tradition.
Each of the six possibilities requires detailed analysis.21
While it is beyond the scope of a survey article to convey the full force of the complete halachic dialogue among the various authorities, an effort has been made to present, along with each opinion, some of the Talmudic proofs and some of the questions raised in opposition to each reason.
A. Creating Something New (Molid)
The possibility that the use of electricity on Shabbat violates the prohibition of molid was first suggested by Rabbi Yitzchak Schmelkes (Beit Yitzchak 2:31). Rabbi Schmelkes states that just as the Sages forbade creating a new fragrant scent in one's clothes on Shabbat, molid reicha (Beitza 23a) - an action which Rashi explains was prohibited because "one who creates something new is almost as one who performs a biblically forbidden act" - so too they forbade creating anything new on Shabbat, including appliances made "new" through the use of electricity or the creation of a current flow. Thus, he states, creating a current flow (molid zerem) is rabbinically forbidden because in doing so one has created something new - a functioning appliance.
Rabbi Shlomo Zalman Auerbach and many others22 disagree with Rabbi Schmelkes' thesis. Essentially these authorities state that Rabbi Schmelkes' theory must be wrong because any creative act which is routinely done and undone throughout the day cannot be included in the rabbinic prohibition of creating something new. Moreover, there are many examples of "new creations" which were not prohibited by the Sages. Merely because creating a new fragrance is prohibited does not imply that all new "creation" is prohibited on Shabbat. Rabbi Auerbach insists that only a limited number of actions were prohibited in the Talmud because of molid, and one may not extrapolate from these limited examples that creating anything else new (like electrical current) is rabbinically prohibited.
A proof to this can be found in a responsum of the Chacham Zvi (#92), which limits the prohibition of molid to the application of a fragrance to one's clothes. However, he permits one to apply fragrance to many things other than clothes. In addition, Rabbi Auerbach (Minchat Shlomo p. 74) provides numerous examples of new "creative actions" which the rabbis never forbade.
B. Building (Boneh)
The second possible basis for prohibiting the use of electricity can be found first in the works of Rabbi Abraham Isaiah Karelitz, commonly referred to by the name of his magnum opus, Chazon Ish.23 He states that it is likely that completion of a live circuit constitutes a forbidden act of building (boneh) on Shabbat. He reasons that completing a circuit renders a previously useless wire into a functional wire, and this is analogous to competing a building or wall. In addition, completing a circuit is analogous to assembling an appliance composed of numerous parts - which halacha defines as building - and is thus prohibited on Shabbat.
The Chazon Ish's position has aroused great debate among halachic scholars. The most vigorous and thorough critique of this position is found in the eleventh chapter of Rabbi Shlomo Zalman Auerbach's work, the Minchat Shlomo. While Rabbi Auerbach advances numerous critiques of the Chazon Ish's position, the most crucial aspect of his criticism is that opening a circuit which is designed to be opened and closed routinely cannot be considered an act of building or destroying.24 Closing a circuit is analogous to closing a door - an action which the halacha does not consider to be "building" since the door is intended to be opened and closed constantly.25
The overwhelming majority of halachic decisors appears to side with Rabbi Auerbach. As the Encyclopedia Talmudit (18:166) states:
From the writing of numerous achronim it appears that turning on an electrical circuit does not violate the prohibition of fixing an object [metaken mana and ma'keh bepatish] or building [boneh].26
Nevertheless, at the very least halachic authorities do take into consideration the opinion of the Chazon Ish on this issue when rendering decisions regarding electricity.27
C. Ma'keh Bepatish (Completing an Appliance)
Some authorities believe that causing an electrical appliance to work is a biblical violation of ma'keh bepatish28 (literally "the final blow of the hammer" but generally understood to mean the final act in finishing any product and making it useful29). These authorities cite as precedent those who prohibited winding a watch for this reason.30 Purely by analogy, these authorities argue that since an electrical appliance is useless before electricity is added to it, the introduction of electric current causes it to become a useful piece of equipment, and is therefore prohibited because of ma'keh bepatish.
Rabbi Shlomo Zalman Auerbach (Minchat Shlomo pp. 69-73) and Rabbi Yaakov Breisch (Chelkat Yaakov 1:53) strongly disagree. They argue that since an appliance is designed to be frequently turned on and off, that action cannot be categorized as ma'keh bepatish. Moreover, they state that it is accepted that an action is considered to be ma'keh bepatish only when that final act is permanent or involves great effort. But, since one does not ordinarily intend to turn on an appliance permanently and since turning on an appliance does not involve great effort, this action cannot be considered as violating ma'keh bepatish. The majority of authorities agree that ma'keh bepatish cannot be the source of the prohibition to turn on electrical appliances.31
The fourth reason advanced to prohibit turning on appliances during Shabbat is that the mechanical switching on or off of an electrical circuit generates sparks.32 As a general rule, the creation of sparks is forbidden under the rubric of the rabbinic prohibition against producing sparks from wood or stones. Numerous authorities maintain that an electrical appliance that generates sparks is thus prohibited.33
A number of factors, however, indicate that this prohibition is inapplicable to the sparks created by turning mechanical switches on or off. First, these sparks are created unintentionally (davar she'eino mitkaven), and no prohibition exists when there is no intent to perform an action on Shabbat and that action might not occur.34 Second, since these sparks are so small that one cannot detect any heat when touching them, and typically they are not visible, it is possible that these sparks should not be considered fire.33 Additionally, the advent of solid state technology36 and sparkless (arcless) switches frequently makes this issue technologically moot. Thus, Rabbi Auerbach (Minchat Shlomo pp.86-87) states "practically (lehalacha) there isn't even a rabbinic prohibition in the unintentional creation of sparks."
E. Additional Fuel Consumption
Another possible problem is raised by the author of Chashmal Leor Halacha (2:6). He writes that completing a circuit and causing a current flow sometimes causes additional fuel to be consumed by the power station as a result of the increased need for electricity. Causing additional fuel to be consumed perhaps is to be considered in the category of burning which is forbidden on a biblical level. Thus, it might be prohibited to draw increased current on Shabbat.
Rabbi Auerbach (quoted in Shmirat Shabbat Kehilchata 1:23 n. 137) disagrees.37 First, one is only indirectly causing increased fuel consumption (grama). More significantly, greater fuel consumption is not inevitable or even likely when one turns on one appliance, because statistically it is likely that at that very moment, someone elsewhere has turned off an electrical appliance, thereby elimination the need for increased electric output. Finally, outside Israel the power plants are operated by gentiles (if they are not fully automated), and hence the prohibition would only be in directing a non-Jew to violate the Shabbat, which is only a rabbinic prohibition.
F. Heating a Wire or Filament
One other possible prohibition is raised by the Chazon Ish.38 He states that when the current passing through a wire raises the wire's temperature above the temperature at which a human hand pulls away because of the heat (yad soledet bo),39 it is considered to be an act of "cooking" (bishul) and thus prohibited. The Chazon Ish states that this "cooking" is prohibited even though the person who turns on the appliance is unaware that it is occurring and does not intend that there be any "cooking."
Rabbi Auerbach (Minchat Shlomo, p. 107) disagrees and states that a metal wire can only be "cooked" when one intends to soften (or temper) the metal and it glows. Although the wire is lightly softened, once the electricity is extinguished the wire immediately returns to its original state. In addition, one who turns on an appliance has no intention to soften the wires; hence this action can not be defines as "cooking" from the perspective of halacha.40
Additionally, in the last twenty years, solid state technology has become dominant, and fewer and fewer appliances have wires that are heated (vacuum tubes), thus making this argument factually obsolete.
G. Electrical Appliances Permitted
Rabbi Auerbach (Minchat Shlomo 74, 84), after rejecting all the potential sources discussed above for prohibiting the use of electricity when no light or heat is generated, concludes that, at least in theory, electrical appliances that use no heat or light (e.g., a fan) are permitted on Shabbat and Yom Tov. However, he declines actually to permit their use absent urgent need. He states:
In my opinion there is no prohibition [to use electricity] on Shabbat or Yom Tov... There is no prohibition of ma'keh bepatish or molid... (However, I [Rabbi Auerbach] am afraid that the masses will err and turn on incandescent lights on Shabbat, and thus I do not permit electricity absent great need...) ... This matter requires further analysis.Rabbi Auerbach additionally states that since the tradition forbids the use of electricity, and this tradition received near unanimous approval from rabbinic authorities in the normal course of events observant Jews should accept this tradition (even though he feels it is based on incorrect premises) and operate under the presumption that the use of electricity without light or heat is a violation, of rabbinic origin, based on molid.41 Only in the case of urgent need does he allow one to rely on his opinion that electricity is permitted where no heat or light is generated.
In cases of urgent need it is possible to accept Rabbi Shmelkes' ruling that electricity is prohibited as a form of creating something new (molid) as correct, and perhaps still use electrical appliances. For example, in a recent work, Shealot Uteshuvot Merosh Tzurim pp. 501-509, Rabbi Shmuel David was asked by kibbutz members if it was permitted to use a telephone on Shabbat to call a veterinarian for advice on a mysterious plague that had struck the chicken coop. This plague was so devastating that it would destroy nearly all of the animals if professional help were not received. Furthermore, these chickens were a significant source of financial support to the kibbutz. Rabbi David ruled that it was permitted to use the telephone if it was used in an unusual manner. He reasoned that in all likelihood, Rabbi Auerbach is correct and no prohibition is violated, and even if the Beit Yitzchak is correct, in cases of great need (perhaps even great financial need, and certainly physical need), since this case involved suffering to living creatures (tza'ar ba'alei chaim), rabbinic prohibitions when done in an unusual manner may be violated.42
So, too, when one is forced to choose between prohibited actions, it is appropriate to realize that the consensus is that electricity without light and heat is a rabbinic and not a biblical violation. For example, if one has to bring a person to the hospital on Shabbat, it is unquestionably preferable to call a taxi (for a gentile driver) by telephone, which most consider only a rabbinic violation (see section IV:b), than to drive there oneself (which is unquestionably a biblical violation), if the few minutes differential in time are irrelevant.
H. Turning Off Appliances
While the tradition is well established that one does not turn off appliances on Shabbat, the reasons for this prohibition are unclear. Of the six reasons advance above to prohibit turning on electrical appliances, the inverse of three of them is directly applicable to turning off appliances. These three reasons are:
1. Just as turning on a circuit is prohibited because it is a form of building (boneh), turning off a circuit is prohibited because of the biblical prohibition to destroy (soter). (Chazon Ish, Reason B Above).
The viability of each of these reasons in the context of prohibiting turning off an appliance is closely connected to its correctness in prohibiting turning on such appliances. For example, if turning on an electrical appliance is actually building (boneh), then it is logical to maintain that turning off an appliance violates the complementary biblical prohibition to destroy (soter). On the other hand, if for the reasons explained above boneh is inapplicable, so too is soter.43
It is also worth noting that the tradition in observant houses is typically to refrain - absent need - even from practices that are apparently permissible according to all written discussion of this issue. For example, these authors are aware of no authority who prohibits one to reduce current flow (without turning off) a solid state appliance on Shabbat. Yet it is clear that the tradition is not normally to engage in such conduct on Shabbat.44
The reason advanced to prohibit the use of electricity on Shabbat when no light or heat is generated are quite diverse. They range from the biblical prohibition of building to the rabbinic prohibition to create something new (molid) or to tradition without any precise basis in the laws of Shabbat. Whatever the basis, accepted practice generally prohibits the use of electricity on Shabbat even when no light or heat is generated.
III. Electricity and Lights on Yom Tov
The use of light (and electricity) on Yom Tov differs significantly from that of Shabbat in one key respect. On Shabbat it is prohibited either to start or increase a flame. However, on Yom Tov it is permitted to add fuel to an already burning flame.45 For example, while it is prohibited to light a match on Yom Tov, it is permitted to transfer a flame from one candle to another candle. Thus it is prohibited on Yom Tov, just like on Shabbat, to turn on an incandescent light - since turning on a light is (as explained above) halachically identical to lighting a match.46 Unlike Shabbat, however, it is likely that on Yom Tov this is only rabbinically prohibited, as most authorities maintain that even creating a new flame on Yom Tov is only a rabbinic violation.47 So, too, it is only rabbinically prohibited to turn off a light on Yom Tov.48
There are a number of authorities, however, who feel that it is permissible to turn on incandescent lights on Yom Tov. Three distinct reasons have been given to justify this practice.49
1. Turning on a light is only indirectly causing the light to go on. This type of indirect action (grama), while generally prohibited on Shabbat, is permitted for rabbinically prohibited actions on Yom Tov.
A number of rabbinic authorities, including Rabbi Tzvi Pesach Frank and Rabbi Yechiel Michel Epstein (the author of the Aruch Hashulchan), accepted the approach that permitted turning on lights on Yom Tov.52 However, this is not the approach of most authorities. The consensus of rabbinic authorities maintain that it is prohibited to turn on an incandescent light on Yom Tov.53 After summarizing all those authorities who discuss this issue and concluding that it is prohibited to turn on lights during Yom Tov, Rabbi Ovadia Yosef (Yabia Omer, Orach Chaim1:19; 2:26), states:
Since there are those who permit the lighting of electric lights on Yom Tov, one should not strongly rebuke people who turn on lights on Yom Tov - specifically since many congregations in the Diaspora have this tradition with the approbation of their rabbis. Nonetheless, it is proper to explain to such people in a mild voice that most rabbinic authorities are strict about this matter, and the law follows the majority.This is supported by the fact that of the six substantive reasons advanced in part II for prohibiting the use of electrical appliances on Shabbat, five are equally applicable to Yom Tov.54 Thus each of the authorities discussed in part II who prohibit even electrical appliances without light or heat on Shabbat must maintain that incandescent lights are prohibited on Yom Tov for the same reasons. For example, if switching on a circuit during Shabbat is prohibited because of building (boneh) then turning on such a circuit on Yom Tov is also prohibited.55
It also appears that any authority who permits turning on lights on Yom Tov (except perhaps for those who do so based on the indirect causation analysis, see note 55) must agree with the position of Rabbi Auerbach that there is no halachic obstacle to using electricity when no light and heat are produced. Authorities who permit turning on lights on Yom Tov must have rejected the reasoning of those who forbid activating a circuit based on the prohibition of building (boneh), finishing a product (ma'keh bepatish), creating a new electrical flow based on molid (creating something new), or creating sparks, as there is no distinction between Shabbat and Yom Tov for these prohibitions. This analysis would add a large number of eminent decisors to the list of those who agree with Rabbi Auerbach that electricity used solely as a form of mechanical energy is theoretically permitted on Shabbat (and actually permitted in cases of great need).
Two distinct approaches have been taken to the use of electricity on Yom Tov. Most authorities maintain, and it is the accepted practice of observant Jews, to treat Yom Tov like Shabbat, and not to turn on lights or use electrical appliances on Yom Tov. A minority opinion, and the practice of some observant Jews, allows turning on lights (and perhaps other appliances also) on Yom Tov. All agree that it is prohibited to turn lights off on Yom Tov.
IV. The Use of Refrigerators, Telephones, Radios or Televisions, and Generating Static Electricity on Shabbat and Yom Tov
The previous sections explained the rules concerning the use of electricity on Shabbat and Yom Tov. This section summarizes the halachic discussion concerning four common appliances: refrigerators, telephones, radios, and televisions, as well as the question of generating static electricity on Shabbat. Since this section will integrate the rules developed into the general framework of the laws of Shabbat, four Shabbat rules will be used throughout this section. They are:
1. Melacha she'einah tzricha legufah (an action not needed for its result). This occurs when one does a prohibited action on Shabbat not intending to commit the action prohibited by halacha. For example, pouring water on a field to dispose of the water, rather than to irrigate the field, is a melacha she'eina tzericha legufah. This is normally a rabbinic violation.
The opening of a refrigerator door on Shabbat has been the topic of vigorous debate in past decades. Opening the refrigerator door allows warm air to enter, thus causing a drop in temperature which causes the motor to go on sooner. If one accepts that turning the motor on during Shabbat is prohibited, then it would appear that opening the refrigerator door on Shabbat when the motor is not already56 running is prohibited. Indeed, many prominent rabbinic decisors have adopted this position.57 However, many authorities58 assert that one is permitted to open a refrigerator even when the motor is off.59
The prohibition associated with intentionally starting the motor in the refrigerator must be discussed first. It is possible that no prohibition exists at all since, as explained above, Rabbi Auerbach asserts that no prohibition is violated when initiating an electric current if there is no heating element. Thus, Rabbi Auerbach contends that no Shabbat violation occurs when one causes a motor to run which in turn causes a gas to vaporize and thereby cools down the refrigerator; Minchat Shlomo, p. 84.
Moreover, Rabbi Auerbach writes that even the Chazon Ish, who delivered that completion of an electric circuit constitutes a forbidden act of building (boneh), would concede that no violation occurs when one causes the motor to start prematurely by opening the door. Rabbi Auerbach maintains that the Chazon Ish limits the biblical prohibition of building to placing the plug in the socket. However, causing the motor to start earlier cannot be considered "building" for two reasons. First, an act cannot be defined as building if that act will occur later naturally. Turning on an appliance could only be defined as building because human intervention is required to stop this action. However, the refrigerator's motor will go off automatically shortly after it has begun to work. Second, the reasoning of the Chazon Ish is based on bringing the appliance "from death to life."60 However, by allowing hot air to enter, one has not caused any change in the operation of the refrigerator. The refrigerator is operational before opening the door; once the temperature reaches a certain degree, the motor will start. Hence, Rabbi Auerbach states that even the Chazon Ish would concede that causing the motor to start early cannot be considered "building." Accordingly, all agree that no biblical prohibition is violated by causing the motor to run prematurely.
A rabbinic prohibition, though, is violated by starting a current according to the Beit Yitzchak. Therefore, possibly one violates at most rabbinic prohibition in causing the motor to run.61 Rabbi Auerbach and others (see note 58) maintain that a number of factors are present in this case so as to render this rabbinic prohibition inapplicable. First, by opening the door one does not directly cause the motor to run since there is a thermostat that serves as an intermediate regulator.62 Indirect actions are generally permitted only in cases of great monetary loss.63 But Rabbi Auerbach rules that rabbinic prohibitions performed in an indirect fashion are permitted even absent potential monetary loss. Since one does not intend to cause the motor to go on, this action is an unintentional side effect (davar she'eino mitkaven) and therefore permitted.64
Moreover, rabbi Auerbach argues by way of reductio ad absurdum, if one rules stringently and prohibits opening the refrigerator door lest it cause the motor to run prematurely, then it should also be forbidden to open the windows or curtains, or bring hot foods in close proximity to the refrigerator. These actions, he points out, also cause the motor to run earlier than it would have otherwise.
Rabbi Yaakov Breisch65 objects to this reasoning and rules that indirectly causing prohibited actions cannot be permitted on a regular basis. Rabbi Auerbach counters that only when one intends the resultant action to occur is it prohibited if performed regularly.
Common practice among observant Jews in America appears to accept those authorities who allow the opening of the refrigerator door even if the motor is not running.
Five different aspects of using the telephone are relevant from a halachic perspective: lifting the receiver, dialing, talking, holding the receiver, and returning the receiver to its place.
Lifting the receiver involves a number of possible problems. Most significant, it closes an electric circuit, thereby causing a current flow. If one adopts the position of the Chazon Ish, one has violated a biblical prohibition; Rabbi Schmelkes would assert that a rabbinic prohibition has been transgressed. Additionally, in some (but not many) telephone systems, a light goes on when a person lifts a phone off the hook. Rabbi Levi Yitzchak Halperin (Maaseh Choshev 1:60) advances the argument that causing the dial tone to work violates the rabbinic prohibition of "making a noise be heard" (hashma'at kol).66 This seems incorrect, however, as that sound is not audible to any other person, and in fact most authorities67 who discuss telephones do not mention the noise made by the dial tone as a halachic problem.68
The next area of discussion concerns the prohibitions related to dialing. Again, circuits are completed, bringing about a biblical prohibition according to the Chazon Ish, a rabbinic prohibition according to Rabbi Shmelkes, and possibly no prohibition according to Rabbi Auerbach. Rabbi Benzion Uziel (Mishpatei Uziel 1:13) writes that when dialing, one has violated the biblical prohibition of "the final blow" (ma'keh bepatish) by turning the telephone into a functional object. Rabbi Ovadia Yosef (Yabia Omer 1:20) disagrees because the phone is a fully functional object prior to the dialing. Dialing a number is considered to be merely using the phone, not fixing it.
Rabbi Yitzchak Schmelkes and Rabbi Chaim Ozer Grodzinski69 assert that since dialing causes a phone to ring, one has violated the rabbinic prohibition of causing noise to be heard (hashma'at kol). Rabbi Shlomo Zalman Auerbach (Minchat Shlomo pp.75-76) suggests that since it only indirectly cause the phone to ring, one may be lenient, because indirect causation of rabbinic prohibitions is permissible on Shabbat.70
The next issue is speaking on the telephone. Rabbi Yitzchak Schmelkes (Beit Yitzchak 2:31) states that one violates the rabbinic prohibition of "causing a noise to be heard" (hashma'at kol) since one's voice is heard elsewhere due to the telephone. Rabbi Auerbach and Rabbi Eliezer Waldenberg, however, disagree71 in light of Ramo's ruling (Shulchan Aruch, Orach Chaim 338:1) that no prohibition of "causing a noise to be heard" applies when the sound is created by a human voice.72
Talking on the telephone causes an increase in the current used. Whether increasing current usage is prohibited on Shabbat is a major halachic issue.73 Rabbi Auerbach maintains that there are no halachic prohibitions associated with causing an increase or decrease in current, in appliances without a heating element or glowing filament.
Upon close examination, Rabbi Auerbach appears to be correct even according to those who typically disagree with him. For example, while the Chazon Ish states that completion of a circuit constitutes an act of building, once a circuit has been completed, one does not "build" anything by increasing current. Similarly, Rabbi Schmelkes, who states that creating a current violates a rabbinic prohibition to create something new, probably would concede that one may increase current. The paradigmatic example he uses of creating something new is the prohibition to created a new scent in a garment. However, it is permitted according to many authorities to increase the intensity of a fragrance in a garment once a scent already exists, because the prohibition is limited to creating a new scent.74
Those who believe that turning on an appliance violated the prohibition of "the final blow" (ma'keh bepatish), would limit this assertion to turning on the appliance and not increasing current. After the appliance has been turned on, it has been rendered into a usable item and no further prohibition of "the final blow" is violated when increasing current. Finally, even if one views the creation of sparks as a halachic problem (see section II:F above), no such problem exists when increasing current because an increase in current does not lead to increased creation of sparks.
Rabbi Yitzchak Yaakov Weiss and Rabbi Binyamin Yehoshua Silber75 disagree and prohibit increasing current for two reasons. First, it is far from universally accepted that one may increase the intensity of a fragrance already present in a garment (see n. 74). Second, increasing current may not be analogous to increasing the intensity of a scent. One can argue that in many instances the increased current is what enables a desired activity to take place and thus, is more analogous to adding on an entirely different additional scent to a garment,76 which all agree is prohibited.
Whether one is permitted to increase current has many halachic ramifications. A few examples are adjustment of (not to turn on or off) a hearing aid,77 speaking directly to someone wearing a hearing aid,78 going up on an automatic elevator,79 and riding an escalator.80 The consensus of rabbinic opinion appears to side with Rabbi Auerbach on this matter.81
The last set of problems that arises from the use of a telephone on Shabbat are "hanging up" and returning the phone to its holder. The Chazon Ish would prohibit these acts since one opens circuits, thereby violating a biblical prohibition of destroying (soter). As explained above (section II), many authorities disagree with the Chazon Ish's position on this issue.82
C. Radios and Televisions
Turning on radios or televisions involves completion of a circuit; current flow, as shown above involves a biblical prohibition according to the Chazon Ish, and a rabbinic prohibition according to Rabbi Schmelkes . Since newer radios and televisions do not contain heating elements or glowing filaments, Rabbi Auerbach raises theoretical possibility that turning on the radio per se does not involve any prohibition, as he does not accept either the opinion of the Chazon Ish or Rabbi Schmelkes as correct. However, it is well established that by turning on a radio, one violates the rabbinic prohibition of "causing a noise to be heard with an instrument designed for this purpose" (hashma'at kol al yedei keli hameyuchad lekach). Thus, even Rabbi Auerbach rules that a rabbinic prohibition is present when one turns on a radio.
Whether one may raise the volume on Shabbat depends upon whether one is permitted to increase current flow on Shabbat.83 However, whether moving the dial from one station to another constitutes a violation of the rabbinic prohibition of "making a noise be heard" is disputed. Rabbi Waldenberg (Tzitz Eliezer 3:16:12:5) believes that a violation takes place because no coherent sounds are heard in between stations. By tuning in the desired station, one has caused noise to be heard which would not have been heard previously. Rabbi Auerbach (Minchat Shlomo p. 67) disagrees because the broadcasters are the ones who create the sound and only they violate the prohibition of "creating a noise that is heard."
D. Static Electricity
Whenever it is permissible to separate (or wear) clothes on Shabbat if that action will generate static electricity is a topic that a number of decisors have addressed. If one adopts Rabbi Auerbach's aforementioned lenient ruling regarding the creation of sparks during use of a circuit, one might be lenient in this regard as well. Indeed, Rabbi Auerbach is cited (Shemirat Shabbat Kehilchata 15:72) as maintaining that the unintentional creation of static electricity from clothes does not pose a halachic problem.
Rabbi Eliezer Waldenberg (Tzitz Eliezer 7:10) rules leniently in this regard also. Rabbi Waldenberg Argues that these sparks last hardly a moment and have no impact whatsoever. In addition, there is no precedent for these sparks in the labor performed during the construction and functioning of the tabernacle, and hence there is no precedent whatsoever to classify the creation of these sparks as forbidden acts of labor. Therefore, he rules that the unintentional creation of static electricity does not pose a halachic problem.84 At the conclusion of his responsum, Rabbi Waldenberg adds another consideration to be lenient in this regard - that one does not intend to create the static electricity.
Rabbi Ovadia Yosef's primary reason to rule leniently in this matter (Yabia Omer 5:27 and Yechave Daat 2:46) is based on the lack of intent to create the sparks. Rabbi Yosef writes that unintentional acts from which no benefit is derived (pesik resha delo nichah lei) are permitted if the underlying prohibition is itself only a rabbinic violation; he agrees that if a biblical violation would occur, they are prohibited. This leniency is not universally accepted.85
The use of specific appliances is enveloped in the controversy of electricity generally. Many authorities permit opening refrigerator doors on Shabbat whether the motor is on or off. Some permit this only when the motor is on. While most authorities agree that the use of telephones is prohibited on Shabbat, Rabbi Auerbach asserts that it is possible that telephones are not prohibited. While all agree that neither radios nor televisions can be used on Shabbat, there is dispute over the nature of the prohibition. The unintentional generation of static electricity is permitted.
V. Timers on Shabbat and Yom Tov
The use of timers on Shabbat and Yom Tov involves two distinct halachic issues, one of which has been settled and one of which has not. The first is whether it is permitted to set a timer on Friday so that a prohibited action will take place on Shabbat. The second is whether it is permitted to adjust that timer on Shabbat in order to change the time when the action will occur.
A. Using Timers Set on Friday
Setting a timer on Friday so that a prohibited act will occur automatically on Shabbat seems at first glance to be very similar to a well-established halachic rule. Based on a Talmudic discussion (Shabbat 17b-18a), Rambam (Shabbat 3:1) states:
It is permitted to start an action [melacha] on Friday even though that action is completely on Shabbat, since it is only forbidden to start work on Shabbat. However, when the work is done by itself on Shabbat, it is permitted to benefit from that work.
So too, Shulchan Aruch (Orach Chaim 252:1) states:
It is permitted to start an action on Friday near darkness even though the work cannot be completed on Friday and can only be finished on Shabbat.
Two exceptions to this rule were established. The Talmud (Shabbat 47b) states that one may not place a dish of water around a flame (which is emitting sparks) on Friday lest one shift the water on Shabbat and thus extinguish the flame.
More relevantly, the Talmud (Shabbat 18a) quotes in the name of Rava that it is prohibited to add wheat on Friday to a water mill that runs automatically on Shabbat, since the mill produces a large amount of noise and this noise denigrates Shabbat (zeluta deShabbat).86 Furthermore, people will say that the owner of the mill is running it on Shabbat (Ramo, Orach Chaim 252:5). Rav Yosef is quoted in the Talmud as disagreeing with Rava and permitting any action done prior to Shabbat even if it creates large amount of noise.
Rishonim disagree as to which opinion, Rava's or Rav Yosef's, is accepted as normative by halacha. Rabbenu Tam, Rambam and Rif all accept the opinion of Rav Yosef.87 On the other hand, Rabbenu Chananel, Rosh, Semag and Semak all appear to accept Rava's approach.88 Rabbi Karo in the Shulchan Aruch states that it is permitted to place wheat in a self-grinding water mill on Friday (Orach Chaim 252:5). Rabbi Isserles (Ramo), however, adds:
There are those authorities who prohibit placing wheat in the mill on Friday. We [Ashkenazic Jewry] should worry about the prohibition of creating sound. This is the proper approach ab initio [lechatchila]. In cases of financial loss, it is permitted to be lenient.
Based on this stricture of the Ramo, there are some who claim that using a timer on Shabbat should be prohibited when it creates audible or visible action.89 For example, absent some significant need, both Rabbi Feinstein90 and Rabbi Auerbach (Minchat Shlomo pp. 68-69) agree that this rule prohibits one from playing a radio on Shabbat even if it is left on for all of Shabbat. Placing a radio on a timer is analogous to putting wheat into a water mill. Both cause noise on Shabbat and arouse suspicion that its owner has violated the laws of Shabbat. Hence, they rule that it is rabbinically prohibited to set a radio on a timer or to let it run the entire Shabbat.91
Others have advanced different reasons to prohibit timers on Shabbat some claim that merely because the Talmud permitted finishing a prohibited action on Shabbat when it is started on Friday, it does not mean that a timer which does the entire action on Shabbat is permitted92. Others have argued that just as it is forbidden to place a dish of water around a sparkling flame (see above) lest one adjust it, so too, it is prohibited to use a timer lest one set it on Shabbat.93 Finally, others argue that the only time it is permitted to start an action on Friday and finish on Shabbat is when no benefit is derived from the action on Shabbat. However, when a prohibited action is done for the sake of having the product on Shabbat, it is prohibited.94
The consensus of the achronim as well as the accepted practice is not in harmony with any of the opinions which prohibit timers. As the Encyclopedia Talmudit ("Electricity" 18:679) states:
Many of the achronim permit one to set a Shabbat clock on Friday - and this is the common practice - even those who prohibit creating a sound permit the use of timers... since all know that these timers are set before Shabbat.Essentially, since it has become common practice to use timers, there is no appearance of impropriety when timers are used. This approach has been accepted by most contemporary decisors such as Rabbi Waldenberg, Rabbi Breisch, Rabbi Henkin, Rabbi Auerbach, Rabbi Ovadia Yosef, the Chazon Ish, Maharam Schick and many others.95
B. Adjusting Timers on Shabbat and Yom Tov
Before discussing whether a substantive prohibition exists to adjust a timer on Shabbat and Yom Tov, it is necessary to address a threshold question: are timers muktza? If timers are muktza, it is obviously prohibited to adjust them.
In a brief and cryptic responsum, Rabbi Moshe Feinstein asserts, without explanation, that one may not adjust a timer during Shabbat and Yom Tov because the timer is muktza.96 Other decisors have offered reasons for this assertion. Rabbi Benjamin Silber states97 that a timer is muktza "due to concern for monetary loss" (muktza machmat chesaron kis).
Rabbi Auerbach (Minchat Shlomo, p. 111) and Rabbi Ovadia Yosef (Yabia Omer 3:18:2) disagree and rule that timers are not muktza. They advance a number of reasons including the argument that the fact that the owner is presently using the timer makes it absurd to state that it is muktza due to a concern for monetary loss. This category of muktza is limited to items which are not regularly used and carefully stored due to concern that the item be damaged. However, one cannot reasonably assert that a timer is withheld from use as it is presently being used.98 This argument appears to be correct; it is difficult to grasp why a timer should be considered muktza if it is permitted to adjust it on Shabbat.99
Assuming that timers are not muktza, four distinct issues need to be addressed.
1. May one adjust the timer so that the appliance will start earlier than originally intended, (e.g., move the dial so that a light scheduled to go on at midday goes on at 11 a.m)?
This question is dependent on Whether adjust in such a timer involves direct or indirect causation (grama) of the prohibited work. As a general rule, actions done through indirect causation only are on a much lower level of prohibition on Shabbat; in many circumstances they are completely permitted. The Talmud (Shabbat 120b) states:
[Deuteronomy 12:4] states "One may not do any work;" however, work done directly is prohibited, but work done indirectly is permitted.
The definition of "indirect" for the purposes of Shabbat, however, is in dispute. The resolution of this issue resides to a great extent in the harmonization of two apparently contradictory Talmudic texts. In Shabbat 120a the Mishnah states that it is permitted to place barrels of water in the path of a fire with the intent that the barrels catch fire, burst, and their content extinguish the flames. The Talmud (Shabbat 120b) explains that this is an example of indirect causation which is permitted in cases of need. Elsewhere the Talmud (Bava Kama 60a) distinguishes between tort law and Shabbat rules, by stating that for the purposes of Shabbat rules one is responsible for indirectly caused activity (but in tort one is not). The example the Talmud gives is one who is winnowing (separating wheat and chaff) on Shabbat violates the biblical prohibition by throwing the wheat into the air and letting the wind separate the wheat from the chaff. This is prohibited even though it is done indirectly and requires the presence of an additional force (the wind) to complete the action. The question that emerges is why is the barrel case permitted and the winnowing case forbidden?100
Three answers are given. The first answer posits that the critical distinction is the time delay. The barrel case is permitted because the fire will not destroy the barrels until a considerable amount of time has elapsed, whereas the wind separates the wheat and chaff immediately. According to this definition, because there is a clear time delay between the action and the effect, this would be indirect causation. Since actions done via indirect causation are permitted on Shabbat in case of need or in order to facilitate performance of a mitzvah, a timer set to go on at midday could be adjusted at 9 a.m. so that the appliance will go on at 10 a.m., if this were a case of need or mitzvah. On Yom Tov, indirect causation is permitted even absent special need, and thus such adjustments are always permitted according to this reasoning.101 This is the view of Rabbi Ovadia Yosef and others.102
The second position, that of Rabbi Joseph B. Soloveitchik and others, states that the critical factor is whether the additional force needed to finish the action is present at the time of human activity. Winnowing in the wind is prohibited only when the wind is blowing at the time the wheat is thrown into the wind; the barrel case is permitted since one is placing the barrels away from the fire. Placing the barrels actually in the fire would be prohibited.103 Since, when adjusting a timer the additional force needed to finish the action, namely the rotation of the dial, is present at the time of human activity, all adjustments that hasten an action are prohibited. Thus, Rabbi Soloveitchik rules that under no circumstances may one adjust the timer so that an appliance will begin to operate earlier than expected.
A third view asserts that the critical factor is whether the indirect process used is the normal process. If the indirect process is the normal one, it is prohibited on Shabbat. Otherwise it is permitted. The barrel case is permitted only because it is not the normal manner to extinguish fire through a time delay. Winnowing, however, is frequently done through wind power.104 According to this approach, adjusting a timer is prohibited since it was designed to be used in this manner; however, placing ice cubes (or hot water) on a thermostat to increase the flow of heat (or cold air), would be permitted since that is an indirect and unusual manner of making the adjustment.
2. May one adjust the timer so that an appliance operates later than originally intended? E.g., move a dial on a timer so that a light set to go on at midday, now goes on at 2 p.m.)
In this type of adjustment, no prohibited act occurs because one merely is maintaining the status quo of no work taking place. Thus nearly all authorities permit this type of adjustment.105 However, Rabbi Auerbach (Minchat Shlomo p. 111) cautions that this permissive ruling most likely does not apply to those timers where the timer is adjusted by removing and reinserting a peg.106 In those timers where the dial is rotated, adjustment to delay current flow is permitted.107
3. May one adjust the timer so that the electric current is extinguished earlier than expected? (E.g., a light on a timer is set to go off at midday and one wants to move the dial so as to turn the light off at 10 a.m.).
Adjusting a timer to extinguish an appliance prematurely involves the same considerations as adjusting the timer to extend the current flow. According to Rabbi Joseph B. Soloveitchik's definition of indirect causation, such an action is forbidden. If one accepts time delay as the critical factor in determining whether an action is a result of direct or indirect action, then in case of need or mitzvah one may adjust the timer to extinguish current flow earlier than expected; Yabia Omer 3:18.
One distinction, though, does exist between causing current to flow or be terminated. When the current flow turns on a light, a biblical violation occurs, whereas terminating a current flow involves at most a rabbinic violation (see sections I and II). Rabbi Auerbach (Minchat Shlomo p. 110) states that since the halacha is unclear as to which definition of indirect causation is correct, one should avoid manipulating a timer to hasten an action which, if prohibited, would be a biblical violation. He does however, permit the adjusting of timers where only rabbinic prohibitions are present.
4. May one adjust the timer so that the electric current is extinguished later than expected? (E.g., a light is set to go off at midday and one wishes to move the dial so as to delay the turning off until 2 p.m.).
Some authorities maintain that delaying extinguishing a light is forbidden, since it is analogous to adding fuel to a fire, which is a violation of "burning" (mavir).108 Most authorities109 argue that this is incorrect and that it is analogous to shutting a window so as to prevent the wind from extinguishing a flame - one is only maintaining the status quo by removing an impediment to its continuation, as in situation (2) (moving a dial on a timer so that a light set to go on at midday, now goes on a 2 p.m.)
While initially a subject of some controversy, it has now become accepted that one may use a timer set on Friday to control all appliances. The issue of adjusting timers on Shabbat has yet to be settled. Some authorities prohibit any adjustment of a timer on the grounds that it is muktza. Even if timers are not considered to be muktza, some authorities prohibit adjusting a timer to start or terminate current flow earlier than expected. Other authorities, accepting a different understanding of causation, permit this. Adjusting a timer to delay the onset of current flow appears not to violate any Shabbat prohibition other than muktza according to most authorities.
The use of electricity on Shabbat and Yom Tov is a relatively new, and exceedingly complex, area of halacha. The variety of positions taken by the decisors is broad, and these differences are extremely relevant to the conduct of observant Jews. It is the near unanimous opinion that the use of incandescent lights on Shabbat is biblically prohibited. Beyond that, there is little agreement. Some authorities maintain that any time a circuit is opened or closed a biblical violation occurs. Other authorities insist that the use of electricity absent lights is only a rabbinic prohibition. Still other authorities accept that in theory the use of electricity without the production of light or heat is permitted - although even those authorities admit that such conduct is prohibited, absent great need, because of tradition.
The variety of grounds prohibiting the use of electricity is reflected in discussion of specific appliances. Many authorities permit opening a refrigerator door on Shabbat even if the motor is off; some do not. While all concede that the radio and television cannot be used on Shabbat and Yom Tov, the nature of the prohibition is in dispute. So, too, all but Rabbi Auerbach concede that a telephone cannot be used on Shabbat (even he prohibits it absent great need) - however there is no consensus as to the source of the prohibition. The use of timers is equally in dispute. While nearly all concede that timers may be set on Friday to work on Shabbat, adjusting such timers on Shabbat and Yom Tov is still in dispute.