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17 – Electricity and Electrical Appliances

01. Turning on Electric Lights and Appliances

It is prohibited by Torah law to turn on an electric light bulb or activate an electric heating element, because when the bulb is turned on or a heating element activated, the filament incandesces (see above, 4:5 and n. 3, regarding fluorescent bulbs), and this is a form of Hav’ara prohibited by the Torah. While it is true that in the past, people did not generally produce heat or light by heating metal, we nevertheless find that heating metal for any purpose was prohibited by Torah law. Thus Rambam writes that if one heats metal with the intention of tempering it afterward by plunging it into cold water, he transgresses the Torah prohibition of Mav’ir (MT 12:1). Clearly, then, heating metal is forbidden by Torah law if it accomplishes some purpose.

Extinguishing a light bulb or heating element is only rabbinically prohibited. It is different from a normal act of Mekhabeh, whose purpose is to create charcoal (as explained above 16:5). In contrast, turning off an electrical appliance creates nothing, so its prohibition is rabbinic.

The Torah forbids performing prohibited melakhot by means of electrical appliances. Thus, activating an electric flour mill on Shabbat constitutes a violation of Toĥen, operating an electric mixer on Shabbat violates Lash, and so forth for all melakhot. Although the person is not manually grinding or kneading, since he presses the button or flips the switch to turn the appliance on, all melakhot performed by the appliance are viewed as melakhot performed by him (Oraĥ Mishpat §70; Aĥiezer 3:60).

Just as one may not turn on an electrical appliance by pressing a button, so too one may not activate something by remote control. Even though there is no direct contact between the finger pressing a button on the remote control and the appliance, since this is the normal way to turn on such appliances, it is forbidden just as manual activation is forbidden.

02. Is Using Electricity a Torah Prohibition or a Rabbinic Prohibition?

One may not activate electrical appliances and devices such as telephones, microphones, alarms, doorbells, fans, air conditioners, and computers on Shabbat. Even if these appliances do not contain an incandescent filament or heating element and do not perform any of the 39 melakhot, it is still forbidden to use them on Shabbat. Aĥaronim disagree, however, whether the prohibition is by Torah law or rabbinic.

Some maintain that using any electrical appliance violates the Torah prohibition of Mav’ir. They maintain that electricity has the same status as fire since, like fire, it has energy and power that can be harnessed. Rav Kook favors this position, arguing that the key aspect of fire is not its appearance, but rather its power to illuminate, heat, and provide power. Indeed, the Sages state that there are different types of fire (Yoma 21b), including some that do not burn and destroy. One example of this is the fire that Moshe saw at the burning bush (Rav Kook, Oraĥ Mishpat §71). R. Uziel agrees with this approach, adding that turning on electricity is also prohibited as a form of Metaken Mana since activating an electrical appliance renders it useful (Mishpetei Uziel, OĤ 2:36:2). Ĥazon Ish (OĤ 50:9) maintains that turning on an electrical appliance is prohibited on account of Boneh, because completing a circuit creates a kli: when electricity flows through a device, an electrical wire within comes to life and activates the device. Thus, one who completes a circuit builds an implement, and one who breaks a circuit demolishes it.

Many others maintain, however, that using electrical appliances that do not contain an incandescent filament and do not perform one of the 39 melakhot is only prohibited rabbinically, as it is considered a weekday activity. Additionally, some maintain that turning on appliances is prohibited because it is creating a new entity on Shabbat (Molid), as it creates a new electrical current in the wires (Beit Yitzĥak). No Torah prohibition is involved, because there is no “fire” in appliances without an incandescent filament. There is no problem of Boneh, because an electrical circuit cannot be considered a kli, that is, an implement or receptacle. This is the opinion of R. Shlomo Zalman Auerbach (Minĥat Shlomo 1:9-12) and R. Eliezer Waldenberg (Tzitz Eliezer 1:20:10).

In practice, le-khatĥila we defer to the opinion that using electricity is a Torah prohibition. In times of need, when there are additional reasons to be lenient, we rely upon those who believe that using electricity is only a rabbinic violation.[1]

[1]. According to Rav Kook, using electricity is prohibited on account of Mav’ir. Therefore, one may not speak into a microphone, as this increases the electric current. His responsa on the subject are not so well known, since Responsa Oraĥ Mishpat, in which they appear (§70-71) was printed in 1979, thirty years after the main debates among contemporary Aĥaronim. At the time, Ĥazon Ish was inclined to say that use of electricity is prohibited by Torah law on account of Boneh, but many disagreed with him, including R. Shlomo Zalman Auerbach and R. Eliezer Waldenberg. Nevertheless, other Aĥaronim share Rav Kook’s opinion that the prohibition on electricity is due to Mav’ir. These include Mishpetei Uziel, OĤ 2:36:2; Yaskil Avdi 5:38; Brit Olam, Ha-mav’ir Ve-hamekhabeh 1; R. Yosef Messas’s Responsa Mayim Ĥayim, OĤ §134. Also see the entry on “ĥashmal” in the Encyclopedia Talmudit, which focuses on the opinions that disagree with Ĥazon Ish and maintain that the prohibition is rabbinic. One should be aware that according to Ĥazon Ish, if an appliance is already on, increasing the current to amplify the power of the appliance is not prohibited by Torah law. However, according to Rav Kook, who believes using electricity is prohibited because of Mav’ir, increasing the current is prohibited by Torah law as well.Many contemporary authorities accept the opinion of R. Shlomo Zalman Auerbach that there is no Torah prohibition involved in using electricity. However, le-khatĥila they still take into account the opinion that maintains it is prohibited by Torah law (see Yabi’a Omer 1:20; Minĥat Yitzĥak 2:112; and many additional works). Igrot Moshe (OĤ 3:42, 3:55, and 4:84) maintains that the status of the prohibition is unclear. In practice, although many state that in principle the prohibition on using electricity is rabbinic, in fact they relate to the prohibition of turning on electrical appliances as if it were prohibited by Torah law. Thus, even in cases of uncertainty and cases where electricity is required for the sake of a mitzva, to avoid substantial loss, or to help someone who is bothered by a minor illness, they are not lenient and prohibit using electricity via a non-Jew or when activated with a shinui, despite the fact that each of these scenarios would constitute a shvut di-shvut (see above 9:11). Only in cases of true necessity do they take into account the opinion that the prohibition is rabbinic. Therefore, the only way these appliances can be used on Shabbat is if they are turned on before Shabbat. In times of true necessity they can be used through grama (above 9:9), meaning that one’s actions will not directly or immediately cause the appliance to turn on. Examples of the permitted use of electricity on Shabbat include wearing a hearing aid (section 3 below) and adjusting the setting on a timer (as explained below in n. 6). For appliances that appear to work normally but have a built-in grama mechanism, see section 18 below. Regarding the use of computers, see below 18:1 and Harĥavot.

03. Electrical Appliances That Produce Sound (Telephones and Microphones)

As we have seen, the prohibition on using electrical appliances on Shabbat includes microphones and telephones.

Even if a phone is in use before Shabbat, or if a microphone is turned on before Shabbat, one may not speak on the phone or use a microphone on Shabbat, because doing so increases the electric current running through it and violates a Torah or rabbinic prohibition. In addition, the Sages banned hashma’at kol (producing sound) with an object specifically designed for this purpose. Many maintain that one who speaks into a microphone transgresses this prohibition (based on Rema 338:1). Furthermore, using a microphone resembles a weekday activity. It also may seem to belittle Shabbat, as those who hear the amplified sound are likely to think that the microphone was activated on Shabbat (Igrot Moshe, OĤ 3:55).[2]

Nevertheless, one who is hard of hearing may use an electric hearing aid that rests on or inside the ear on Shabbat as long as it is turned on before Shabbat and he does not adjust the volume on Shabbat. When he wants to go to sleep, he should remove the device without shutting it off. In the morning, he may put it back in without turning it on. Although we stated that one may not use a microphone or telephone because speaking into it increases the electric current, this prohibition applies only when someone speaks directly into them. However, when speaking normally, the activation of the device in the wearer’s ear is secondary and therefore a form of grama, which is permitted when truly necessary. Furthermore, there is no problem of producing sound on Shabbat or belittling Shabbat since the sound is heard only by the wearer.[3]

Just as one may not turn on a microphone before Shabbat with the intention of using it on Shabbat, so is leaving on an intercom over Shabbat to hear the voices of people coming to visit, or to hear what is going on in the children’s room. To be sure, if one simply speaks normally in the room and not directly into the intercom, the prohibition is less severe since it is then a case of grama. It is nevertheless prohibited, because it is a weekday activity, it belittles Shabbat, and it produces sound with an object designed for that purpose. However, if the intercom was accidentally left on over Shabbat, as long as one does not intend to use it he may speak in a normal fashion in the room with the intercom.[4]

[2].If a Jew in the United States who does not observe Shabbat calls a Jewish friend in Israel when Shabbat is over in Israel but while it is still Shabbat in the U.S., the latter may not speak with him, because he is benefiting from his friend’s Shabbat desecration. However, a Jew in Israel may speak with a non-Jew who calls him when it is Shabbat in the U.S., since a non-Jew is not obligated to keep Shabbat (SSK 31:27).

[3]. There is no problem of hashma’at kol since the sound is only heard by the wearer of the device. The only problem is the electrical operations of the hearing aid. Indeed, some prohibit the use of hearing aids (Dovev Meisharim, Levushei Yom Tov §15; R. Yosef Shalom Elyashiv cited in Orĥot Shabbat 26:23). However, in practice many have permitted the hearing-impaired to use hearing aids, including Igrot Moshe, OĤ 4:85. Those who maintain that turning on an electrical appliance without an incandescent filament is rabbinically prohibited because it creates a new flow of electricity in the wires do not view increasing the current as a new creative act. At worst, it might be deemed a weekday activity, in which case one may be lenient in the case of a great need. Similarly, for those who believe that turning on an appliance is prohibited on account of Boneh or because it is creating a kli, there is no problem here; since the hearing aid is already on, increasing the current creates nothing new. Based on these rationales, the following authorities permit the use of a hearing aid: R. Shlomo Zalman Auerbach; Tzitz Eliezer 6:6; SSK 34:28; Yabi’a Omer 1:19:19; Minĥat Yitzĥak 2:17. See Encyclopedia Talmudit vol. 18, pp. 731-732. It is true that Rav Kook in Oraĥ Mishpat §71 prohibits speaking into a microphone, because the speech causes electric current to flow. He explains that this cannot be considered grama since the result is direct and immediate. It seems, though, that since the sound waves resulting from normal speech are only converted to electric current once they reach the hearing aid, this can be considered ko’aĥ sheni (“secondary power”), a form of grama, as explained in San. 77b and Ĥullin 16a. Grama is permitted under pressing circumstances, as explained in Shabbat 120a, SA 334:20, and Rema ad loc.; see above, 9:9.

[4]. One who uses a microphone fully intends to speak into it, and this is the normal way to amplify a voice, so it is not considered grama. In contrast, if one simply speaks normally in a room that has a baby monitor and thereby projects his voice over the intercom, since this is not the normal way to converse and his mouth is far from the intercom, it is considered ko’aĥ sheni and thus grama, as in the case of a hearing aid (though this requires further study; see Harĥavot). However, since the sound can be heard in the room with the receiver, it is a weekday activity and belittles Shabbat. It might also be considered hashma’at kol (Rema 338:1; Oraĥ Mishpat §71; also see Rema 252:5). In contrast, if the intercom was left on accidentally, then since one who speaks in that room is using it only via grama, and he is not interested in making his voice heard, this is a case of psik reisha de-lo niĥa lei in the case of a rabbinic prohibition, where one may be lenient in a case of need. In pressing circumstances, such as when one is sick, one may be lenient and leave an intercom on. See Terumat Hagoren §79. Yalkut Yosef (vol. 5, pp. 403-405) permits this even le-khatĥila. One should only rely on this leniency under pressing circumstances.

04. Elevators

One may not operate an elevator on Shabbat. Pressing the elevator buttons involves Torah prohibitions or, minimally, rabbinic prohibitions. However, some “Shabbat elevators” are set to operate automatically, meaning that they are set before Shabbat to stop on every floor or every other floor, at which point the doors open on their own for a predetermined amount of time and then close on their own. The elevator then continues on its way. There is a difference of opinion among the poskim regarding these elevators.

Some prohibit using a Shabbat elevator, maintaining that using it is a weekday activity. Additionally, entering the elevator causes its motor to use more electricity when the elevator goes up and down (Ĥelkat Yaakov, OĤ §144; Minĥat Yitzĥak 3:60; Ĥut Shani vol. 1, p. 206; R. Shmuel Wosner).

Others maintain that one may go up in a Shabbat elevator but not down. This is because when the elevator goes down, the extra weight helps produce electricity. Thus one who rides the elevator has a hand in generating electricity (R. Levi Yitzĥak Halperin, Ma’aliyot Be-Shabbat).

A third opinion maintains that a Shabbat elevator may be used. Since the settings are in place before Shabbat, and no action needs to be taken on Shabbat to make the elevator work, there is no prohibition. The fact that the elevator has a system that determines the weight of the passenger, which in turn tells the motor how much power to use, and even makes use of the additional weight to produce electricity, is of no interest to the rider. As long as the elevator goes up and down according to its settings, the passenger does not care about the elevator’s electricity-conserving mechanisms. Therefore, the actions caused indirectly by his entry into the elevator are not attributable to him at all (it is a psik reisha de-lo niĥa lei via grama; this is the position of R. Yosef Eliyahu Henkin; R. Isser Yehuda Unterman; R. Shlomo Zalman Auerbach in SSK 23:58; Prof. Ze’ev Lev in Teĥumin 2; and R. Yisrael Rosen in Teĥumin 5.)

In practice, the lenient position is the primary one, while those who are stringent are commendable. In a case of need, even those who are normally stringent may be lenient. Those who are lenient must be careful not to enter or exit the Shabbat elevator when the door is about to close, so as to avoid causing it to reopen. Even for those who are lenient, it is better if the automatic system is programmed under the supervision of an organization that specializes in halakha and technology, as this can help ensure that entering the elevator does not turn on a light or the like and minimize the prohibitions involved according to the stringent view.[5]

[5]. The lenient position is the primary one, as its reasoning is compelling. Furthermore, it does not seem reasonable to view entering an elevator as worse than grama (as this is not a direct action but ko’aĥ sheni). Some are lenient even le-khatĥila in a case of grama (Taz 514:7). To be sure, most poskim permit grama only in cases of need (SA 334:22), but here the grama is combined with a psik reisha, so it is permitted even le-khatĥila (Minĥat Shlomo 1:10:6; see above 9:9 and Harĥavot). In any case, even according to those who do not allow entering a Shabbat elevator, the prohibition is rabbinic, since one who enters the elevator does not intend to do a melakha. Since the poskim disagree, the law follows the principle that we are lenient in cases of doubt about a rabbinic rule.

05. Using Electricity that Was Produced on Shabbat

Power supply is a vital need of the State of Israel all week, including Shabbat. Interrupting or impairing the supply can endanger human life. Hospitals are full of devices that depend on the supply of power, and even in private homes there are people who are dangerously ill who rely on electrical devices to stay alive. Police officers and security forces use electrical equipment, and without electricity they would be unable to respond properly to emergencies. On cold days, many homes are heated using electricity. If the electricity were to be withheld on Shabbat, babies and sick people would likely be at risk. Very hot days can also pose a certain risk for those who are ill and require air conditioning. In addition, since nowadays we store food for an extended amount of time in refrigerators and freezers, this food may spoil if the electricity is cut off. In a large population, some would likely contract food poisoning, which can be life-threatening.

Therefore, it is necessary for the Israel Electric Corporation (IEC) – whose employees are predominantly Jewish – to supply electricity nonstop, even on Shabbat. If there is some impairment to the supply of electricity in a particular location, whatever is needed to fix it must be done. Since technicians may fix the grid on Shabbat, everyone may benefit from the electricity that is subsequently generated, even though it was restored on Shabbat. The only exception is if a power outage takes place in a small area where it is known for certain that there is no risk to human life involved, in which case the repair may not be made on Shabbat. If it was nevertheless repaired by Jews on Shabbat, one may not benefit from the electricity until an hour after Shabbat. (R. Shlomo Zalman Auerbach, quoted in SSK ch. 32 n. 182; below, 26:6).

Much to our dismay, it is known that IEC workers perform activities on Shabbat that are not essential to guaranteeing the electricity supply, but that are for the purpose of saving money. Furthermore, if there were greater awareness of Shabbat observance, it would be possible to automate the entire electricity-generating system and eliminate the need for human intervention without extra expenses. It would only be necessary to have a few workers in the power stations, monitoring the system and troubleshooting emergencies. However, since in fact the IEC does not try to avoid performing melakha on Shabbat, several leading rabbis ruled that one should not use its electricity on Shabbat (but rather use a local generator) to avoid benefiting from Shabbat desecration or supporting it in any way. (See Ĥazon Ish, OĤ 38:4.)

In practice, though, this electricity may be used on Shabbat, even in Israel. It is true that the IEC could take measures before Shabbat to avoid some of the Shabbat violations. Nevertheless, when its technicians do what is necessary to guarantee the electricity supply, they are not desecrating Shabbat, since electricity is necessary for people to live. Because of this, everyone may benefit from the electricity. Since the consumers do not benefit from the melakhot performed by the IEC technicians for the sole purpose of saving money, and from their perspective it would be better if the procedures were automated, they may benefit from the electricity on Shabbat (see Ha-ĥashmal Ba-halakha vol. 2 ch. 1; Menuĥat Ahava 1:24:1). We have recently learned of efforts to automate the grid and prevent Shabbat desecration.

06. Timers

Shabbat prohibitions become forbidden at the onset of Shabbat, but before Shabbat begins, one may take actions whose effects will continue into Shabbat. A prominent example of this is using a timer (“Shabbos clock”). Such timers are connected to the power supply and to an appliance, and its settings control the flow of electricity, determining when the device will turn on and off. This is how, nowadays, we can set electric lights to go on and off over the course of Shabbat. One may leave on lights before Shabbat and set the timer to turn them off at bedtime, on again at lunch time, and off again for the afternoon before turning on again for se’uda shlishit. Similarly, one can use a timer to turn on an electric oven or fan, setting it so that the appliance will go on and off at the desired times.

If one sets a timer to turn off the lights at 11 PM, but then decides that he would like to study Torah until midnight, some say that he may not delay the time that the lights will be extinguished by adjusting the timer’s settings, as in their opinion, the timer is an integral part of the lighting system, and the Sages forbade taking any action that effects a change in the duration of the lights’ operation. This can be inferred from the talmudic case of attaching an oil-filled container to an oil lamp, which the Sages forbid out of concern that one might remove some of the oil on Shabbat (Shabbat 29b; Beitza 22:1).

Others, including R. Shlomo Zalman Auerbach, offer a different perspective. They maintain that delaying the time the lights will go out is comparable to the case of one who is sitting in a room with a lit oil lamp. If the wind starts to blow though his window, threatening to extinguish the light, everyone agrees that he may close the window, even though this allows the lamp to burn longer. Since he is not doing anything to the lamp itself, but merely preventing the wind from blowing it out, there is no prohibition. Similarly, one who extends the settings of a timer is not doing anything to the light itself or to the electrical appliance, but merely preventing the timer from turning them off. Assuming that this action is permitted, the switches on the timer are not muktzeh, and they may be adjusted.

Since the rationale of those who are lenient is compelling and also accords with the widespread practice, one may rely on their opinion even le-khatĥila. Therefore, one may take action to extend the current state of affairs. If the electricity is off, one may extend the time that it will remain off and have the lights go on later. If the electricity is on, he may lengthen the time that it will remain on, and have the lights go out later. Similarly, if the lights are off, one can move the light switch to the off position, so that when the timer eventually restores the power, those lights will not go back on (SSK 13:26-33).[6]

However, one may not change the timer so that lights or appliances will go on or off earlier. For example, if the timer was set so that the lights would go off at midnight, but it turns out that people want to go to sleep earlier, one may not adjust the timer’s settings to make the lights go off earlier. Although he is not turning them off directly because his actions will not have any effect until later, nevertheless indirectly causing lights to go off is rabbinically forbidden. Similarly, if the timer was set to turn the lights on at 10 AM, it may not be adjusted to make the lights come on earlier, as indirectly causing lights to go on is rabbinically prohibited.[7]


[6]. Some maintain that making any change to the settings of an electric timer is prohibited by Torah law (Yaskil Avdi 7:23), while others maintain that only certain kinds of changes are prohibited by Torah law (Igrot Moshe, YD 3:47:4; Az Nidberu 3:25 and 8:32). If this opinion is correct, then the problem of muktzeh also comes into play. Nevertheless, the logic of those who are lenient is very compelling, as explained in Harĥavot. First, the stringent position is based on the opinion of Rosh and those who follow him, with which many disagree (above ch. 16 n. 1). Second, it would seem that even Rosh would permit in this case, as the action of adjusting the timer is not done directly to the lights. Indeed, R. Shlomo Zalman Auerbach writes thus in Minĥat Shlomo §13, as does R. Ovadia Yosef in Yabi’a Omer, OĤ 3:18.It should be added that when the lights are off, one may increase the time they will remain off, even if they will go on in the interim period. In other words, if the lights are off during the night, and are set to go back on at 10 AM and turn off again at noon, one may adjust the timer so that the lights will go off at 11 AM. The principle is that while the lights are off, one may cause them to be off for a longer period of time. This is true whether the current state is being extended, or whether the future state is being extended following a period when the lights will be on. Similarly, while the lights are on, one may cause them to be on for a longer period of time, even if in the interim they will turn off for a certain amount of time (SSK 13:30).

[7]. This applies under normal circumstances. However, in cases of need, those who are lenient allow causing a timer to turn the lights on earlier. According to most poskim, using a timer is considered grama, which some permit even le-khatĥila (Taz), and most permit in times of need (as explained above 9:9). This is the position of R. Shlomo Zalman Auerbach as cited in SSK 13:29, and of R. Ovadia Yosef in Yabi’a Omer, OĤ 3:18. Therefore, when one is sick (even if he is not dangerously ill), if the lights are disturbing his sleep and the timer is set to turn off the lights in a couple of hours, the settings may be changed so that the lights will go out in half an hour instead. An additional reason to be lenient is that turning off lights is only a rabbinic prohibition (above, section 1). In a case of dire necessity, one may make the lights turn on earlier for the sake of a mitzva, such as if the lack of light would cause one to waste much time that would have been spent learning Torah. In deference to the stringent position, however, it is proper to use a shinui when making the adjustment.

07. Thermostat Controls

The laws of thermostat controls are the same as those of an electric timer. Some poskim maintain that one may not adjust a thermostat. According to R. Shlomo Zalman Auerbach and others, one may change the setting if it will lead to the extension of the current state.

For example, if one set the thermostat of an electric oil-filled radiator to medium before Shabbat, but on Shabbat realizes that it is hotter than he had expected, he may lower the setting of the thermostat once it has switched the radiator off. Thus, he ensures that the radiator will remain off for a longer period of time, and the heating element will work for a shorter period of time. However, one may not lower the thermostat while the radiator is on, because this changes the current state by causing the heating element to cycle off sooner.

If, during the course of Shabbat, one wants a radiator to stay on for longer, he must wait until the radiator has cycled on, and the temperature of the radiator has reached at least yad soledet bo (at least 71 degrees Celsius). Then he may turn up the thermostat so that the radiator will stay on for longer. However, if he does this when the temperature is below yad soledet bo, he transgresses Bishul, because he is causing the oil inside the radiator to heat up. Once the radiator has cycled off, it is not permissible under any circumstances to turn up the thermostat, because this will change the current state and may lead to the radiator turning on immediately.

The same rules apply to air conditioners and refrigerators that have manual thermostats. When the compressor has cycled on, one may turn down the temperature, which will keep the refrigerator or air conditioner on longer. When the compressor has cycled off, one may turn up the temperature, which will keep the machine off longer (Minĥat Shlomo §10; SSK 23:24).

Of course, all of this assumes that there is no display recording the temperature. However, if the thermostat is adjusted by pressing buttons to change the temperature, and this is shown in an electronic display (as is the case with many air conditioners), then it is prohibited, both on account of Kotev, and because each press of a button makes direct use of electricity.

08. Opening a Refrigerator or Oven, and Entering an Air-Conditioned Room

If opening the door of a refrigerator causes an electrical event to occur, one may not open the door on Shabbat. Most refrigerators have an electric light inside that goes on automatically when the refrigerator door is opened. Thus, if the light has not been removed before Shabbat, one may not open the refrigerator on Shabbat. There are also refrigerators where a fan turns on or off whenever the door is opened. These refrigerators and any with similar electrical mechanisms may not be opened on Shabbat.

In contrast, if it has been ensured that opening the refrigerator will not turn anything on or off, one may open the door on Shabbat. Indeed, some permit opening a refrigerator when the compressor has cycled on but prohibit opening the refrigerator when the compressor is off, as opening the door causes warm air to enter the refrigerator. Since the compressor is activated by an internal thermostat, opening the refrigerator may cause the compressor to go on immediately, or at least sooner than it would have otherwise.

However, in practice one may open the refrigerator even when the compressor is off. There are a number of reasons for this. First, it is unintentional: The person opening the door does not intend to turn on the compressor. Second, it is uncertain whether opening the door will cause the compressor to turn on, as it is possible that the compressor was about to cycle on anyway. Third, even if opening the door does cause the compressor to cycle on, this was only done indirectly, via grama, as opening the door does not itself turn on the compressor. It simply causes warm air to enter, which may in turn affect the compressor. Accordingly, one does not need to worry about a case where there is uncertainty regarding grama combined with lack of intent.

For the same reason, one may drink cold water from a water cooler without checking whether or not the compressor has cycled on. One may also enter a room that has a working air conditioner that is controlled by a thermostat, even though opening the door may cause the air conditioner to cycle on. First, it is not certain that opening the door will cause the air conditioner to cycle on. Even if it does cycle on, this was accomplished via grama. Similarly, one may open a door or window in a room that has a thermostat-regulated heater or air conditioner. This is because the person opening the door or window does not intend to affect the machine, it is not certain that opening the door or window will in fact do so, and if the machine is affected it will have been accomplished through grama.

However, many are stringent regarding an oven that is controlled by a thermostat and will not open such an oven when the heating element has cycled off. Since it is a small appliance, opening the door is more likely to cause it to cycle on. To avoid this problem, some ovens have a Shabbat setting in which the oven produces a steady heat and does not respond to a thermostat. When the oven is on this setting, all agree that it may be opened and shut at will.[8]

[8]. As explained in 9:9 above, some permit grama even le-khatĥila, while most only permit it in cases of need. Here, even if the act of opening the oven door will definitely turn on the heating element, since he does not intend to turn it on, it is simply a psik reisha de-lo niĥa lei, which is permitted even under normal circumstances. This point is even more relevant if it is possible that the oven would have cycled on even if left alone. In that case, opening the door accomplishes nothing. R. Shlomo Zalman Auerbach writes this regarding a refrigerator (Minĥat Shlomo 1:10), as do R. Ovadia Yosef (Yabi’a Omer, OĤ 1:21) and R. Eliezer Waldenberg (Tzitz Eliezer 8:12). However, many recommend being stringent and opening the refrigerator only when the compressor is already on; only then is it impossible for opening the door to cause the compressor to turn on, as it is already on. Even though the influx of warm air will lead the compressor to stay on for longer, this is not prohibited (Responsa Har Tzvi, OĤ 1:151; Ĥelkat Yaakov 3:179). Nevertheless, the bottom line is that one may open a refrigerator without checking whether or not the compressor is on.The law regarding opening a refrigerator is more lenient than the law regarding opening an electric oven. There are two reasons for this distinction. First, an oven is small, and thus opening the door is likely to cause it to cycle on. There is a slight possibility that this would not be considered grama, but rather a direct action. In contrast, a refrigerator is large, and it is unlikely that opening the door will affect it immediately. If this were to happen, it would definitely be considered grama. Second, according to many poskim, turning on the refrigerator’s compressor is only a rabbinic prohibition, since there is no heating element (above, n. 1). In contrast, turning on the oven’s heating element is prohibited by Torah law according to all opinions. Reflecting this distinction, SSK 1:35 is stringent about opening the door of an electric oven, while when it comes to a refrigerator he records the lenient position as well. In contrast, Igrot Moshe, OĤ 4:74, Bishul 28 is lenient even in the case of an electric oven with a thermostat. He maintains that one may open the door even when the oven has cycled off, because it is an uncertain psik reisha in the case of a rabbinic prohibition (as it is performed via grama), and such a combination is permitted. Regarding opening the door of a room that has a radiator or air conditioner, almost no one is stringent. Since there is a relatively large distance between the door and the air conditioner or radiator, even those who are stringent would agree that this is considered grama. See above 10:17.

09. When the Refrigerator Light Bulb was not Disconnected

If one did not remove or disable the light bulb of a refrigerator before Shabbat, he may not open or close the door on Shabbat, as this will turn the light on or off. If one needs the food in the refrigerator for Shabbat, he may seek the help of a nearby non-Jew. In order to avoid the prohibition of benefiting from a melakha performed by a non-Jew, one should offer him food from the refrigerator, at which point he will open the door for his own benefit. Once the non-Jew has opened the refrigerator for himself, the Jew may take whatever he needs out of the refrigerator as well. Although generally one may not ask a non-Jew to perform a melakha on Shabbat, here one is not asking him to perform a melakha. Rather, one is asking him to open the refrigerator, which also happens to turn on the light. Afterward, in order to continue opening and closing the refrigerator permissibly, one may ask the non-Jew to remove the bulb, because turning off electric lights is only prohibited rabbinically, and one may ask a non-Jew to transgress a rabbinic prohibition for the sake of Shabbat (above 9:11; below 25:2, 5).

If no non-Jew is available, and the food is truly needed, then when the compressor has cycled off, the refrigerator may be unplugged using a shinui, such as by prying the plug out of the socket using a thin piece of wood or plastic. Since the plug is muktzeh, it may not be moved in the normal fashion (below 23:14).[9]

In a case where one is uncertain whether or not the bulb was removed, many poskim maintain that one may open the refrigerator. First, he does not intend to turn on the light, but only to open the refrigerator. If the light does go on, it is a case of psik reisha – he is performing a permitted action, and a second prohibited action takes place collaterally – which is normally prohibited. However, since the prohibited action might not occur, this is a case of an uncertain (safek) psik reisha, which is not prohibited. Although some are stringent in such cases, the lenient position is the primary one.

If the refrigerator was opened and the light went on, food that is needed may be removed. The refrigerator should not be closed. Rather, a towel or some other object should be positioned in a way that prevents the refrigerator from closing and turning off the light. This way, the refrigerator can also be reopened.[10]


[9]. SSK 10:14 permits one to pull the plug using a shinui, but only if it often plugged and unplugged. If this is not the case, he is concerned that unplugging it might qualify as Soter. In 15:3 above I write that even if a particular appliance is not plugged and unplugged regularly, the law follows the majority of plugs (which are plugged and unplugged regularly), and we do not distinguish between types of plug. Therefore, there is no problem of Boneh or Soter. Menuĥat Ahava 1:24:20 is not concerned about this and allows one to remove the plug with a shinui. In any case, as long as a shinui is used, then even concerns of Boneh and Soter amount to a doubt about a rabbinic law, and when necessary one may be lenient. However, it is still forbidden to plug the appliance back in. See Harĥavot for what to do in a case of dire necessity.Nowadays, most refrigerators have near-constant electrical activity, and pulling the plug puts an immediately stop to this activity, resulting in an act of Mekhabeh. Nevertheless, as long as one pulls the plug with a shinui, since the prohibition of turning off electricity is rabbinic, it is a shvut di-shvut, which is permitted for the sake of a mitzva, as explained above in 9:11.

Asking a minor: In cases of necessity, when the food is needed to feed a minor, one may ask the child to open the refrigerator. Since he has no intention of turning the light on, his act of opening the door is only prohibited rabbinically, and several Rishonim maintain that one may instruct a minor to transgress a rabbinic prohibition for his own needs. Some extend this leniency to cases of great need, and when necessary one may rely on them, as explained below 24:5 and in Harĥavot here.

[10]. The status of a safek psik reisha is subject to dispute. Taz permits it, while R. Akiva Eger forbids it. The poskim tend to be lenient in times of necessity, especially when it is a psik reisha de-lo niĥa lei, in which case it is a case of doubt about a rabbinic law, as explained in BHL 316:3 s.v. “ve-lakhen.” SSK 10:15 applies this rule to the case of a refrigerator, as does Menuĥat Ahava 1:24:20. See above, 9:5 and n. 2 and Harĥavot 9:5:8. If the refrigerator has been opened and the light is already on, and one is desperate to close the refrigerator door so that the food will not spoil, he should push the door in the opposite direction and then let it swing shut on its own. This way it is closed via grama. As San. 77b explains, if one throws a rock upward, and it then falls straight down, such an action is considered grama )Orĥot Shabbat ch. 29 n. 38).

10. Dishwashers

A dishwasher may not be activated on Shabbat. This is because one may not use electricity, and additionally because the dishwasher heats water to wash the dishes. This heating is a transgression of Bishul.

One who always clears off dirty dishes from the table and places them directly in the dishwasher may do so on Shabbat as well. Then after Shabbat he can run the dishwasher. However, if he does not generally do this, then he may not do so on Shabbat, as it would amount to preparing on Shabbat for the weekdays, which is forbidden.

One may not even turn on a dishwasher via a timer, because the dishwasher is designed so that it will not go on unless the door is closed. This means that the person who closes the door to the dishwasher after the dishes have been loaded causes it to turn on (SSK 12:37). However, in times of need, when there will be a great need to wash many dishes on Shabbat and it would be extremely difficult to wash them by hand, one may set the dishwasher with a timer. This is because causing it to turn on by closing the door is considered grama. Since an action performed via grama is not a true melakha, in times of need it is permitted (above 9:9; Responsa Me-rosh Tzurim §30).

If one can disable the system that makes the dishwasher’s activation dependent on closing the door, so that the dishwasher will go on at the set time even if the door is not shut, then even in ordinary circumstances one may load the dirty dishes and have the dishwasher wash them during Shabbat (R. Yeĥiel Faust, Le-ohavai Yesh 1).

11. Automatic Doors

One may not approach a door that automatically opens when it senses someone near it. One who does so is viewed as directly triggering the electricity that opens the door. It is immaterial whether the system works through floor sensors, an electric eye, a motion detector, or the like. As we have seen (section 2), according to many, including Rav Kook, turning on an electrical appliance is prohibited by Torah law.

One who finds himself in a hotel or hospital with automatic doors must find an alternative way to enter that does not involve using electricity. If a non-Jew approaches the door in order to enter, a Jew may follow him in (below 25:1-2). But if the person approaching the door is a Jew who does not observe Shabbat, a Shabbat observer may not follow him in, because the Shabbat observer may not benefit from the Shabbat desecration of a fellow Jew. Furthermore, when an observant Jew takes advantage of Shabbat desecration and benefits from it, it is considered a desecration of God’s name. Even though some are lenient in this case, it is proper to be stringent. Only under pressing circumstances, when there is no alternative, may one rely on those who are lenient.[11]

Doctors and nurses may enter a hospital through an automatic door, as their work entails saving lives. Others may then follow them through the door. Ideally, the hospital administration should try to minimize the need for Shabbat desecration and arrange alternative entrances for visitors and staff to enter without activating any electrical devices.

Some say that if one unintentionally came too close to an automatic door, thus causing it to open, he must remain in place, because moving away will cause the door to close. They maintain that he should wait until a non-Jew arrives and ask the non-Jew to stand near him, at which point he can leave. Afterward, when the non-Jew leaves as well, the non-Jew will be the one who causes the door to close. However, if remaining in place causes the Jew anguish, he may simply leave, as he is just walking normally and does not care if the door is open or closed. His act of leaving is a psik reisha de-lo niĥa lei brought about via grama, which is not forbidden. Even if the person who mistakenly caused the automatic door to open did in fact want to enter, in a time of need he may still enter, since the melakha was unintentional. In contrast, if he intended for the door to open but forgot, and only later remembered, that it is forbidden, he should not enter, because one may not benefit from a melakha that was unknowingly  (albeit intentionally) performed on Shabbat (SA 318:1; see n. 11 above and 26:4 below).

[11]. Some are lenient and allow an observant Jew to follow a non-observant Jew through an automatic door, maintaining that this is not considered benefiting from melakha performed on Shabbat, since opening the door is merely removing an obstacle (R. Shlomo Zalman Auerbach in SSK 18:63). Furthermore, if the person who opens the door is considered an unintentional transgressor, in times of necessity one may rely on the opinion of R. Meir that one may benefit from melakha performed by such a person on Shabbat (MB 318:7). In contrast, there are reasons to be stringent. First, many maintain that opening such a door is considered a melakha performed on Shabbat (Igrot Moshe, OĤ 2:77). Second, the scenario of an observant Jew waiting for a non-observant Jew in order to benefit from his Shabbat desecration constitutes a desecration of God’s name. Therefore, one may be lenient only under pressing circumstances.

12. When Entering a Room Causes the Lights to Turn On

One may not enter a room where doing so automatically turns on the lights or air conditioning. While one might claim that he did not intend to turn on the lights or air conditioning by entering the room, the fact is that everyone knows how the system works in such places.

This problem is common in hotel rooms and bathrooms. One who stays in such a hotel must make sure that the system is switched off before Shabbat. If he did not take care of this in advance and is outside his room when Shabbat begins, he may ask a non-Jew to open the door for him. He should further ask the non-Jew to stay for a bit so that the non-Jew will benefit from the lights or air conditioning, since he is then viewed as having turned them on for his own sake, and the Jew may then benefit from them (below, 25:2).

What if the hotel guest is inside such a room when Shabbat begins, and he knows that if he leaves he will cause the lights or air conditioning to shut off? If he can easily stay inside until after Shabbat, or if a non-Jew is due to come shortly to disable the system, it is preferable to wait inside. However, if doing so causes him anguish, he may leave the room or bathroom because the purpose of this system is to save the hotel money by conserving electricity. The hotel guest does not care about that, so it is a case of psik reisha de-lo niĥa lei regarding a rabbinic prohibition (since all agree that the prohibition of turning off the lights or air conditioning is rabbinic). When necessary, in such a case, one may be lenient (above, ch. 9 n. 2).

However, as we saw earlier, once the guest has left his room he will not be able to return to it, because doing so will turn on the lights and air conditioning. The only way for him to re-enter would be with the help of a non-Jew. Therefore, the proper course of action in this case is to ask a non-Jew to disable the system. Then the guest will be able to enter and exit the room as needed.[12]

[12]. The claim that one may enter a room where the lights and air conditioning will automatically turn on since one is not interested in this happening is not legitimate. Part of the reason the system was put into place to begin with was to make one’s life easier by relieving him of the need to turn on the lights and air conditioning every time he enters the room. Just because he does not want it to happen on account of a Shabbat prohibition does not make this a psik reisha de-lo niĥa lei. See Orĥot Shabbat 26:28, n. 41 and Yalkut Yosef vol. 3, pp. 55-56.

13. Intercoms, Security Monitors, and Doorbells at Building Entrances

Some buildings use closed-circuit television (CCTV), in which surveillance cameras transmit images to monitors. A non-Jewish security guard stationed at the entrance keeps an eye on the people who come and go by watching the monitors. When people whom the guard recognizes as residents of the building or their guests arrive at the front door, he pushes an electric button that unlocks the door, allowing them to enter. Since this system is beneficial to the Jewish residents and guests of the building, a Jew may not stand where his image will be captured on the monitor. Similarly, if a Jew wishes to enter the building, he may not press the intercom button to request that the guard unlock the door for him, since using electricity is prohibited.[13]

Therefore, one should make certain that the place where the guard sits is not far from the front door. Then, when a Jew wishes to enter, he can knock on the door while standing out of camera range, so that the guard can see him and unlock the door for him. If the non-Jew elects to open it using the electric release button, the Jew may still enter, since it is also possible for the non-Jew to open the door manually. If the non-Jew prefers to use the door release button, he is doing so for his own convenience, and not for the benefit of the Jew.

If there is a non-Jew entering the building at the same time as the Jew, even if the non-Jew makes use of the electricity, the Jew can follow him in, since the non-Jew is doing this for his own benefit. If it is a non-observant Jew who makes use of the electricity in order to enter, one may not follow him in, since he may not benefit from melakha done by a fellow Jew on Shabbat. Additionally, this constitutes a desecration of God’s name. Although some are lenient in this regard, it is proper to be stringent. Only under pressing circumstances, when there is no alternative, may one rely on those who are lenient (as explained above, ch. 11 n. 11).

If one wishes to enter a building, but no one inside the building hears him knocking and calling out, may he ring an electric doorbell to gain admission? Some maintain that under pressing circumstances one may ring the bell using a shinui, while others forbid this. Under pressing circumstances, when there is no other solution, one who wishes to may rely on the lenient opinion provided that this leniency is not used regularly, as doing so regularly belittles Shabbat.[14]

[13]. In addition to causing electrical activity, one who stands in a place where his image will be captured on the monitor transgresses Kotev as well (on the rabbinic level, since the image is not permanent). See Orĥot Shabbat 15:35 and 26:27. However, when one has no interest in this happening, he may walk where there are cameras or sensors installed, even though his movements cause electrical activity, as explained in the next section.

[14]. According to R. Shlomo Zalman Auerbach and those who follow him in stating that using electricity is prohibited rabbinically, ringing the bell with a shinui renders his action a shvut di-shvut, and under pressing circumstances he may be lenient. However, for those who maintain that using electricity is prohibited by Torah law, even with a shinui it is still only a single shvut, which remains forbidden. Since according to all opinions, ringing the bell with a shinui renders the prohibition rabbinic, there is a rabbinic doubt about whether this is a case of shvut di-shvut or not. Accordingly, one who wishes may be lenient. As I have written above (ch. 9 n. 7), the entire leniency of shvut di-shvut may be utilized only rarely, under pressing circumstances.

If one accidentally presses a doorbell, he should stop pressing as soon as he realizes what he has done, because this act of stopping is not considered an action. If a light will turn on when he stops ringing the bell, some prohibit this (SSK 23:56). Others permit it, insisting that letting go of the bell is not considered an action. (See Kedushat Ha-Shabbat vol. 2, p. 27.) Under pressing circumstances, one may be lenient.

14. Motion Detectors in Public Domains and in the Home

One may walk where security cameras record images of passersby. Since the pedestrian has no interest in being videoed, he is not held responsible for his image being recorded, and there is no prohibition. Similarly, one may pass through a metal detector, since one who goes through is not interested in its electrical activity. One may also walk on a street where there are motion detectors that detect the movements of passersby. Even if a security system turns a light on when it senses movement, one may walk past it, because he is innocently walking through and is not interested in turning on the light. However, if it is not difficult, it is preferable to use an alternate route, since indirectly causing an electric light to go on is not properly respectful of Shabbat.

A private home might have a security system in which the burglar alarm has been disarmed, but the sensors continue working. Consequently, whenever one passes by certain places, LED security lights go on, or images are recorded. Some forbid walking around in such a house on Shabbat since doing so will cause electrical activity. They maintain that if one wishes to walk there, he must either disable the entire system or cover all the sensors so they will not detect a person’s movements. (See R. Mordechai Eliyahu, She’elot U-teshuvot Ha-Rav Ha-Rashi, 5750-5753, p. 174.)

Others permit walking there. This is because one simply wishes to walk, and has no interest in triggering sensors or having his image captured; the only reason he does not deactivate them is because it is so difficult to do (Si’aĥ Naĥum §25). This is the primary position. Nevertheless, if possible, it is preferable to disable the sensors.

One must disable a light that automatically turns on when one approaches the entrance to one’s house, because he benefits from the light in this case. Even if he does not benefit, it is not properly respectful to Shabbat to cause the light to go on. In a case of need, when the system is activated and there is no other way to enter the house, one can crawl through in such a way that the light might not turn on. Even if it is almost certain that the light will still turn on, turning it on by crawling constitutes a shinui. Additionally, he should keep his eyes closed so that he will not benefit from the light when it goes on.

15. Security Systems

When a home security system is necessary for protection against thieves, there are two possible ways to set it up in a halakhically acceptable fashion. The best way is to use a timer. One may set the timer to arm the system during the hours when people are in bed or out of the house and disarm the system during the hours when people are awake and going in and out of the house. The problem with this is that if schedules change, the system needs to be changed, and if doing this involves using electricity, it is absolutely forbidden on Shabbat. If the system has an external timer, one may extend the current state, as explained above (section 6; under pressing circumstances one may also shorten the time, as explained in n. 7).

The second possibility is to use a special key that works via grama. Such a key disarms the security system when turned in one direction and arms it when turned in the other direction. To avoid transgression, the key must not cause any immediate electrical activity. Rather, it activates a mechanism that will eventually activate or disconnect electricity powering the alarm. Even though performing melakha through grama is normally prohibited le-khatĥila, when the only alternative will result in loss, one may be lenient.[15]

Another question regarding security systems relates to monitoring services. In many cases, if a burglar alarms for a home or a car is triggered, the system signals a central monitoring station. Operators at the station see the signal and contact the owner to find out what happened. If the owner does not answer, the operators dispatch security personnel to apprehend the thieves. May one maintain a security system that involves such a service?

Some are stringent and require the owner to demand that the monitoring service refrain from desecrating Shabbat on his behalf. This approach would require the service to use non-Jewish security personnel on Shabbat. Others permit using a monitoring service even if it is staffed by Jews, maintaining that every theft nowadays involves an element of danger to human life. Therefore one may hire a service that employs and sends out Jewish security personnel on Shabbat. In practice, it is proper to use a company that tries to use non-Jewish security personnel on Shabbat. If that is not an option, one may use a company that is not particular in this regard. If the alarm goes off and the service calls to find out if a dispatch is necessary, even if the personnel are non-Jews, one should answer the phone, in order to prevent them from making an unnecessary trip.[16]

[15]. Within this second possibility, there are two permissible options. The first is to set it up so that when the system is shut off via grama, all the sensors stop working, and when it is re-armed the sensors resume working. The advantage of this option is that while people are home, no sensors are activated. The disadvantage is that every turn of the key causes the electrical system to turn on or off. The second option is to arrange that the sensors are always working, while the key simply serves to connect and disconnect the alarm system. The disadvantage of this option is that every movement in the house activates the sensors (see the previous section). The advantage is that turning the key does not cause any recognizable electrical activity. Even when the system is armed, if no thief enters, the alarm will not go off.

[16]. Orĥot Shabbat 23:208 maintains that one may not hire a security service that is under Jewish ownership or hires Jewish workers. In contrast, R. Shaul Yisraeli (Amud Ha-yemini §17) maintains that police may take action against thieves on Shabbat because it prevents danger to human life. Be-mar’eh Ha-bazak 4:43 applies this approach to monitoring services as well. Nowadays, there is an additional reason to be lenient. Thieves in Israel are often connected with terrorists. Just as the Sages allowed people in border towns to defend themselves on Shabbat against robbers of straw and hay (SA 329:6), so, too, people who live anywhere in Israel may defend themselves against the thievery of terrorists (below 27:12). In practice, one should give preference to a monitoring service that tries to hire non-Jewish guards. Nevertheless, this is not absolutely necessary, because the primary position is that preventing theft involves preserving lives as well. Not only that, but one may answer the phone when the monitoring service calls to check if there was a break-in. This is similar to the case of ambulances, which we discuss in 27:10 below. All false alarms cause danger to human life. See Harĥavot.

Connecting a synagogue ark to an alarm system and disconnecting it when the Torah scrolls are taken out to be read must be done by means of grama, that is, using a key that activates or deactivates the system only a few minutes after the key is turned. In Teĥumin 1, Rav Dasberg proposed an excellent solution that does not even require grama. See Harĥavot.

16. Turning Off an Alarm That Went Off on Shabbat

If an alarm goes off on Shabbat because one touched one’s car or entered one’s house carelessly, what should be done? If the alarm goes off during the day and will stop relatively soon, one may not take any action to turn it off. However, what if it will continue to make noise for an extended period during the day or for even a short period at night? If the alarm disturbs people and causes them anguish because it prevents them from sleeping, sets them on edge, and ruins their enjoyment of Shabbat, one may turn it off, as long as one does so via a shvut di-shvut (above 9:11). This is because turning off the alarm is only prohibited rabbinically (see section 1 above), so if one turns it off with a shinui such as by pressing the appropriate button on the remote control with a spoon or the back of his finger, then the action taken is considered a shvut di-shvut. Even if turning off the alarm will make a light go on temporarily, since he does not need this light, it is considered a psik reisha de-lo niĥa lei (above 9:5).

It is true that some forbid this, only allowing one to be lenient if a non-Jew is available to turn off the alarm. For one who follows this position, if his non-observant Jewish neighbors threaten to call the police (which will lead to additional Shabbat desecration), he should tell the neighbors where the remote control is. Then the neighbors can choose to turn the alarm off themselves rather than call the police (Melakhim Omnayikh 10:6).

However, in practice, since this is a case of great necessity for the sake of a mitzva, one may turn off the alarm via a shvut di-shvut (see Be-ohalah shel Torah, OĤ §23; R. Dov Lior in R. Moshe Harari’s Kedushat Ha-Shabbat vol. 1, p. 303).

17. Alarm Clocks, Watches, and Digital Photo Frames

If an electric alarm clock goes off on Shabbat, one may not turn it off, because doing so involves the use of electricity. If the noise is disturbing, the clock may be wrapped in blankets and moved where it will not be heard. If there is no way to minimize the noise, and the ringing is so loud that it is difficult to rest, one may turn off the alarm using a shinui. This follows the principle that a shvut di-shvut is permitted for the sake of a mitzva (as explained in the previous section).

Before the alarm actually goes off, one may press a button to deactivate it. Similarly, one may move an analog clock’s hands in order to delay the time that the alarm will go off. However, one may change the time to an earlier time only for the sake of a mitzva or when there is a great need (above, 6:7). One may not change the time if it involves typing words or digits or any other use of electricity.

One may wear an electronic watch that displays the time. Even if there is a computer inside, one may wear it, since its primary purpose – displaying the time – is permitted (below, 22:8). However, if one knows that he is likely to end up using the computer, he may not wear this watch on Shabbat. Of course, one may not wear a watch that requires him to press a button to see the time, as it is muktzeh.

One may not wear a watch that measures the room temperature and displays it, because the movements of the wearer cause the watch to work. The claim that one is not interested in this feature is patently false; if this were the case such watches would not be made, and if they were made, no one would buy them. However, if the watch detects the temperature but does not display it unless one presses the appropriate button, one may wear the watch. The reason is that the measurement is done via grama, and it is a case of a psik reisha where the person is indifferent toward the result (see above, ch. 9 n. 3).[17]

Some are stringent and avoid wearing a solar-powered watch or an automatic quartz watch that is powered by movement. They are concerned that whenever the wearer moves his hand or enters a well-lit place, he causes the watch to recharge. Others are lenient on condition that the watch would be able to function for a few days without being charged, so that the charging that takes place on Shabbat is not really necessary. One who wishes may be lenient, and one who is stringent should be commended.[18]

A digital photo frame, which stays on all week and cycles through a slideshow of family pictures or scenic views, does not need to be turned off before Shabbat. This is because everyone knows that it is automatic and is on nonstop throughout the week.

[17]. See SSK 28:20, 22 and Yeĥaveh Da’at 2:49, which state that if one need not press an electric button to see the time, one may wear it on Shabbat, and even if it has a calculator built in, it is not considered a base for a forbidden object (basis le-davar ha-asur; Tzitz Eliezer 6:6; Orĥot Shabbat 19:43). Regarding a thermometer and the like, the relevant principle is the one described above in section 14, namely, that causing the activation of sensors that have no present purpose is permitted, but is forbidden if they have a present purpose. Regarding the adjustment of an alarm clock to an earlier or later time, see SSK 28:33; Orĥot Shabbat 8:90-91.

[18]. Those who are lenient maintain that when there is no need to charge the battery, doing so is considered mitasek, as he is moving his arm for entirely different purposes, and the clock is recharged incidentally and without any purpose. This is even more lenient than a psik reisha de-lo niĥa lei; in a psik reisha, one plans to do a particular activity, but in the present case, moving one’s arm is not even an intentional activity. Moreover, there are some who maintain that a psik reisha de-lo niĥa lei is permitted if the activity is rabbinically prohibited, and certainly according to those who maintain that electricity is a rabbinic prohibition, in which case the present example is a rabbinic prohibition on a rabbinic prohibition, as explained above (9:2). Moreover, it is possible that his movements will not generate electricity because the internal battery is already full. Thus, wearing it is a davar she-eino mitkaven that does not reach the level of a psik reisha. See SSK 28:28. However, when the battery needs to be full for Shabbat or even Sunday, he wants it to recharge, and it is therefore forbidden. According to those who maintain that electricity is forbidden by Torah law, one should be concerned that this is a violation of Torah law. According to those who maintain that electricity is forbidden by rabbinic law or on account of Boneh, there are grounds to say that even if the watch cannot continue for much longer on its own, one may still wear it, as carrying the watch or exposing it to light merely adds to the current, which is not forbidden, especially when it is done unintentionally. However, if the watch has already stopped, it is forbidden for anyone to activate it, as stated with regard to winding up the spring of a watch in SA 338:15 and MB ad loc. 15 (see also Ĥelkat Yaakov 1:75; Yabi’a Omer 6:35:8; Tzitz Eliezer 9:20). See Orĥot Shabbat 26:50.

18. Grama Solutions to Halakhic Problems on Shabbat

Several organizations specialize in halakha and technology, devoting themselves to engineering electrical appliances to turn on via grama so that they may be used in cases of need. One such method is called “removing an impediment” (hasarat ha-mone’a). A second method uses a type of scanner that performs a scan every few seconds and turns an appliance on if it determines that a switch has been flipped. Thus, flipping the switch does not turn on the appliance but only causes it to be turned on indirectly. A third method is based on the principle that one may extend the present state: the appliance is set to turn on for one second every few seconds. When the switch is flipped, the next time the appliance turns on, it will not turn off after a second but will remain activated.

Others maintain that one may not use any of these clever stratagems. If an appliance is set to be activated electronically, causing its activation is not considered grama but the normal way of activating it.

In practice, it would seem that if one’s action causes an appliance to turn on within a short time, like it would be turned on during the week, then even if the appliance has been programmed to turn on in a grama-like way, one may not turn it on. The internal workings of the machine are not important; if it turns on in a way that looks normal, then that is not considered grama. Therefore, elevators and automatic doors may not be turned on via grama; since the goal is for them to function in their normal way soon after being turned on, it would not be considered grama. Similarly, one may not travel using a “kalno’it” (an electrical wheelchair or gold cart specially designed for use by the sick, disabled, and elderly on Shabbat), since it operates in the way that one would operate a similar device during the week.

In contrast, when one’s action causes an appliance to turn on only with a significant delay, then if it is brought about indirectly – whether by hasarat ha-mone’a, scanning, or extending the present state – it is considered grama, and such a system may be used when needed. This is the practice regarding arming a security system: if turning a key will cause the system to work via grama, and it will only actually arm itself ten minutes after the key is turned, it is considered grama, and one may do so in cases of great need.[19]

[19]. R. Levi Yitzĥak Halperin, the head of the Institute for Science and Halakha, maintains that in case of need, one may activate devices by “impeding an impediment.” For example, consider a device that is in working order, but a beam of light hitting a particular spot prevents the device from working. When one blocks the light beam, the device begins to work again. Thus, blocking the beam “impedes an impediment” and is considered a grama. According to R. Halperin, technically this is even less severe than grama, but many disagree with him.The Zomet Institute has developed three strategies: 1) Grama by means of a scanner that performs a scan every few seconds. When it detects that a switch has been moved, it activates the device. 2) Extending a state: every few seconds, the device is activated for a second before turning off. If the switch is moved, then the device will not turn off after a second, and the “on” state is thus extended. 3) The device operates constantly at a certain level of power consumption. Flipping the switch merely increases the electrical current. This relies on the numerous poskim who maintain that electricity is forbidden on account of Molid, and consequently adding to the current is not forbidden. Moreover, according to Ĥazon Ish, the prohibition of electricity is based on Boneh, and if the electrical current already exists, it is not prohibited to add to the current. Based on this, they permitted use of a kalno’it. However, according to Rav Kook and those who agree with him, as described above in section 2, increasing a current is forbidden by Torah law. In general, the Zomet Institute relies on the rulings of R. Shlomo Zalman Auerbach, R. Yehoshua Neuwirth, and R. Ovadia Yosef, as detailed in several essays that have appeared in Teĥumin (the journal of contemporary halakhic issues published by the Zomet Institute).

Some say that since these devices were developed for this purpose, the leniency of grama does not apply to them at all. Rather, operating them has the same status as operating normal electrical devices. Moreover, these devices breach the walls that safeguard Shabbat. This is the position of Tzitz Eliezer 21:13; Orĥot Shabbat 29:27; Shvut Yitzĥak, Grama 15:15 in the name of R. Elyashiv; Ĥut Shani vol. 1, p. 206; Binyan Av 4:17. It is also implied in Responsa Aĥiezer 3:60. Certainly all of the reasons to be stringent apply to the kalno’it: according to Rav Kook and those who agree with him (above, section 2), increasing a current is forbidden by Torah law, and according to the remaining poskim, since it moves just as it would move during the week, one may not operate it on Shabbat. They also forbid the kalno’it because it breaches the walls safeguarding Shabbat and belittles its honor.

The proper approach seems to be the one we learned in 9:9 above. That is, a precondition for grama is that the action is done in a way that differs from the normal way of performing the melakha. As long as people perceive the device to be operating normally, it should not be permitted. Therefore, only if the delay is obvious and of significant duration does the device operate in a manner that sufficiently differs from the normal mode of operation on a weekday. Once the mode of operation is considered different, if the activation takes place via grama, that is, by means of a scanner, the removal of an impediment, or the extension of the present state, will it be permissible in a case of need, as is the rule in cases of grama. See Harĥavot.

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