Electricity on Shabbat
Many Jews who strictly observe Shabbat (the Sabbath) refrain from using electrical devices on Shabbat, with the exception of passive enjoyment of devices which were set up before Shabbat. Various rabbinical authorities have pronounced on what is permitted and what is not, but there are many disagreements in detailed interpretation, both between different individual authorities and between branches of Judaism.
In Orthodox Judaism, it is agreed that electrical devices may not be used on Shabbat, but Orthodox Posek (authorities) of Jewish law have disagreed about the basis of this prohibition since the early 20th century. Many Orthodox leaders have held that turning on an incandescent light bulb violates the Biblical prohibition against igniting a fire. However, the reasons for prohibiting the operation of an electrical appliance that does not involve heating metal to glowing temperatures (which is considered like kindling a fire because of the heat and light), are not agreed upon. At least six substantive reasons have been suggested, and a minority (including Rav Shlomo Zalman Auerbach) believe that turning on most electrical appliances is prohibited only because of common Jewish practice and tradition (minhag) and to maintain the spirit of Shabbat, but not for any substantive technical halachik reason.
Some Conservative authorities, on the other hand, reject the argument that turning on incandescent lights is considered "igniting". The Conservative movement's Committee on Jewish Law and Standards has argued that "refraining from operating lights and other permitted electrical appliances is a pious behavior," but is not required, while also stating that the use of some electrical devices (such as computers, cameras, and smartphones which record data) is forbidden on the sabbath.
Although directly operating electrical appliances is prohibited in Orthodoxy, several indirect methods are permitted according to some authorities. For example, Jews may set a timer before Shabbat to operate a light or appliance on Shabbat, and in some cases, they may adjust the timer on Shabbat. Actions that activate an electrical appliance but are not specifically intended to do so may be permitted if the activation is not certain to occur or if the person does not benefit from the appliance's automatic operation. For example, most authorities allow Jews to open a refrigerator door even though it may cause the motor to turn on immediately or later (not certain to occur); however, they prohibit opening the door if a light inside will automatically turn on (certain and of benefit). Some rabbinic authorities permit, under certain conditions, walking past a house with a motion sensor which switches on a light (for example, if the street is already well-lit so there would not be any direct benefit for you).[not verified in body]
Some uses of electricity are especially controversial in Israel because of its majority Jewish population. The use of automated machines to milk cows on Shabbat, an activity that is prohibited if done by hand, is disputed because the farmer may derive economic benefit from the milk, although cows suffer if not milked regularly. The use of electricity from power plants operated by Jews in violation of Shabbat is also controversial because it is normally forbidden to benefit from the action of another Jew's violation of Shabbat. However, because of communal need and other halakhic factors, most religious authorities in Israel permit these uses of electricity.
Incidental prohibitions and leniencies
Many electric devices may not be used on Shabbat for reasons unrelated to electricity. For example:
- An electric stove may not be used to cook food, since all cooking of food is forbidden (bishul).
- An electric lawn mower may not be used, since cutting grass by any means is forbidden (kotzer).
- Use of a computer may violate the prohibition of writing (kotev), either in displaying words on the screen, or saving information to the disk (see fuller discussion below).
Conversely, even if use of an electric device would normally be forbidden on Shabbat, in certain circumstances it may be permitted due to leniencies which apply to all Shabbat prohibitions. For example:
- If violating Shabbat is the only way of saving a human life (pikuach nefesh), one may (and must) violate Shabbat to save a life.
- If one performs an activity which indirectly causes Shabbat to be violated (grama), the level of violation is considered lower. If other reasons for leniency are present, the activity may become permitted under certain conditions.
- If one performs an activity which has the unwanted consequence of violating Shabbat (melacha she'eina tzricha legufa), the level of violation is considered lower. If other reasons for leniency are present, the activity may become permitted.
- If one performs an activity which has the unwanted consequence of possibly (not definitely) violating Shabbat (davar she'eino mitkaven), the activity is permitted on Shabbat.
Of the 39 categories of creative activities prohibited on Shabbat, rabbinic authorities have associated at least three with incandescent lights. The overwhelming majority of Orthodox halakhic authorities maintain that turning on an incandescent light on Shabbat violates a Biblical prohibition on "igniting" a fire (Hebrew: הבערה, hav'arah), because the filament becomes glowing hot like a coal. Some argue instead that it violates the prohibition on "cooking". Another approach is that of Raavad, who would classify incandescent light as a third creative activity: "completing a product" (Hebrew: מכה בפטיש, makkeh bapatish: literally, "striking the final hammer blow").
The Mishnah, in the context of laws prohibiting cooking, states: "One who heats a metal pot may not pour cold water into it to heat [the water], but he may pour water into the pot or a cup to quench [the vessel]." In the Gemara, Rav says it is permitted to add water to cool it, but forbidden to add water to mold the metal. Shmuel says it is also permitted to add enough water to mold the metal as long as that is not his intent, but if he intends to mold the metal it is forbidden. In a different context, Rav Sheshet says that "cooking" a metal filament is forbidden by analogy to cooking spices.
Conservative Rabbi Daniel Nevins has argued that, according to traditional halakhic sources, heating a filament is not prohibited, because the heat does not cause any significant change in the metal and provides no benefit.
Fluorescent and LED lights
While the visible light produced by fluorescent lamps comes from a phosphor coating which luminesces at low temperature, such lamps also include metal electrodes which are heated to a very high temperature, seemingly causing the same halachic issues as incandescent lamps. However, LED lamps contain no hot metal filament and do not have the same halachic questions, though they may be halachically problematic for reasons discussed later in this article.
Other prohibitions may apply to electric devices that do not involve heating metal to glowing temperatures.
The Talmud prohibits infusing a fragrant scent into one's clothing on Shabbat.[clarification needed] According to Rashi, this is because a rabbinic prohibition exists to "create anything new" (molid). Rabbi Yitzchak Schmelkes suggested applying molid to the generating of electric current. Rabbi Shlomo Zalman Auerbach and many others disagree with this application. Among other reasons, they state that molid is a limited category that cannot be expanded past the definitions the Talmudic Sages imposed. Rav Auerbach also stated that molid only applies when the new property is visible (which is not the case with an electric current in a circuit, but is the case when a computer screen is lit up, for example). Nevins has endorsed Rav Auerbach's reasoning.
In any case, molid would seemingly apply only creating an electric circuit, not to extinguishing an existing current (or modifying its strength).
R' Shlomo Zalman Auerbach disagreed vigorously with the Chazon Ish. Among other reasons, he claimed that building and destroying must be fundamentally permanent in nature, whereas most electrical devices are routinely turned on and off at will, and the person who turns it on usually intends that it will be turned off at some later point, and vice versa. Building an item that is fundamentally temporary in nature is at most a Rabbinic prohibition, and Rav Auerbach said that opening and closing a circuit is like opening and closing a door, which is not prohibited at all. Many other Orthodox authorities take this position as well, as does the Conservative Committee on Jewish Law and Standards.
One contemporary authority states that even according to the Chazon Ish, the prohibition of "building" would not apply to changing the state of electric circuits in a computer which is already running.
The Chazon Ish argued, in addition, that closing a circuit to render a device operational might violate the Biblical prohibition of makeh bapatish (striking the final hammer blow, i.e.. completing a product). The argument would be that an electrical device is not complete because it does not function unless the electricity is turned on.
Rabbis Shlomo Zalman Auerbach, Yaakov Breisch, and Nevins strongly disagree because makeh bapatish refers to a fundamentally permanent act that requires great effort, and turning on an electrical appliance is fundamentally temporary because it will be turned off, and requires a minimal amount of effort.
Rabbi Osher Weiss argues that intentionally creating an electric circuit violates makeh bapatish because (in his opinion) any activity that is sufficiently significant and creative is prohibited on Shabbat, and if it does not fit into one of the 38 other forbidden activities, it is categorized as makeh bapatish. He also argues that unintentionally creating a circuit (as often occurs when electronic devices operate in a person's vicinity) is completely permitted, as it does not have the level of significance needed to qualify as makeh bapatish.
Intentionally creating burning sparks, for example by rubbing stones together to make a fire, is prohibited on Shabbat as igniting a fire; it is possible that this prohibition includes the sparks momentarily generated when an electric appliance is turned on. However, R' Shlomo Zalman Auerbach rules leniently for several reasons: the lighting of sparks is undesired, and might not occur, and the sparks are very small so they might not be considered significant. With solid-state technology, the probability of generating sparks is greatly reduced.
Nobel Prize-winning physicist Richard Feynman recounts that he was approached by young rabbis in a seminary who asked him "is electricity fire?". He replied, "no", but asked why they wanted to know, and was shocked that they weren't interested in science at all, but just wanted to interpret the Talmud. Feynman said that electricity was not a chemical process, as fire is, and pointed out that there is electricity in atoms and thus every phenomenon that occurs in the world. Feynman proposed a simple way to eliminate the spark: '"If that's what's bothering you, you can put a condenser across the switch, so the electricity will go on and off without any spark whatsoever—anywhere.' But for some reason, they didn't like that idea either".
Additional fuel consumption
Turning on an appliance may indirectly cause the power plant to consume more fuel, and as so violates mavir, the augmenting of a fire. For various reasons most authorities permit this indirect causation if the power-plant is operated by non-Jews. (If the power plant is operated by Jews, the issue is more complicated. See the section below regarding Israeli power plants.)
Heating a wire or filament
Injecting current into a wire might cause that wire to heat to the temperature of yad soledet bo. According to the Chazon Ish, this would cause operation of such a device to be forbidden. However, R' Auerbach disagrees, saying that heating metal is only prohibited when the intent is to modify the metal (e.g. tempering). Some feel that the prevalence of solid-state technology has made the reality underlying this concern obsolete in many cases.
Rabbi Shlomo Zalman Auerbach rejected any technical prohibition on electricity: "In my opinion there is no prohibition [to use electricity] on Shabbat or Yom Tov... There is no prohibition of Fine-tuning or molid... (However, I [Rabbi Auerbach] am afraid that the masses will err and turn on incandescent lights on Sabbath, and thus I do not permit electricity absent great need...) ... This matter requires further analysis. ... However, the key point in my opinion is that there is no prohibition to use electricity on Sabbath unless the electricity causes a prohibited act like cooking or starting a flame."
However, he considered the use of electricity forbidden by custom, and thus would only permit its use in situations of great need.
In general, from an Orthodox perspective, it is permissible to benefit from most electrical objects during Shabbat, provided they are preset before the start of Shabbat, and the status of the appliance is not manually modified during Shabbat. These include lights, heating, and air conditioning.
Cooking on Shabbat, whether by electrical or other means, is generally prohibited on Shabbat. Food may be kept hot when it is cooked before the start of Shabbat. There are various laws governing how this food is kept hot and served. Often, a blech or crock pot is used for this purpose.
Though most Shabbat observant Jews permit opening and closing a refrigerator during Shabbat, some authorities require that the door only be opened when the refrigerator motor is already running. Otherwise, the motor will be caused to go on sooner by the increase in temperature indirectly caused by the flow of heat from the outside. Most refrigerators and freezers automatically turn the motor on to operate the cooling pump whenever the thermostat detects a temperature that is too high to keep the food cold. However, Auerbach and most authorities permit opening the door because this result is indirect and because there are additional grounds to be lenient.
Additionally, any incandescent light which is triggered upon opening the door must be disconnected before Shabbat. It is not permitted to open the door if the light will turn on because, unlike with the motor running, the light turning on is a Biblical prohibition whereas the motor running may be a Rabbinic prohibition, and also, the light is turned on immediately as an effect of opening the refrigerator whereas the motor turning on is an indirect effect.
Some appliance manufacturers have implemented subtle design aspects to accommodate Shabbat observant Jews. In 1998 Whirlpool's KitchenAid line patented a "Sabbath mode", and since then many manufacturers have followed by offering similar options. These modes typically turn off the electronic displays, disable oven and refrigerator lights that turn on automatically, and use delay timers that allow for permitted temperature controls. According to Jon Fasman, "about half of all ovens and refrigerators on the market (including those made by GE, Whirlpool, and KitchenAid) now have a Sabbath mode."
Some rabbinic authorities have questioned that if a thermostat for a heating or air conditioning system is set prior to the start of Shabbat, if changes made to the temperature of the room in which the thermostat is contained may impact the system's on/off status. Of particular concern is an action that intentionally triggers the thermostat; for example, if the thermostat is set to turn on the room's heat, and an occupant of the room wishes the heater would turn on, opening a window to allow cold air into the room, thereby triggering the heat to turn on.
While most rabbis have ruled that the example of intentionally letting cold air into the room to operate the thermostat constitutes a violation of Shabbat, if the person opens the window for some other, legitimate, reason, and the cold air enters as a side effect, no violation has occurred. Additionally, most agree that if a person who has no intention to operate the thermostat does something which happens to operate it, no violation has occurred.
A few rabbinical authorities have completely forbidden the use of heating or cooling systems controlled by a thermostat on Shabbat, declaring that human actions that trigger the system on or off constitute a violation, regardless of intention.
While (in general) it is prohibited to adjust an electric device so that it turns on or off sooner, many authorities permit adjusting it so an expected change will be delayed and the current state preserved for longer. According to the permissive opinion if a heating system is currently off (because the temperature is currently higher than the thermostat setting), one would be permitted to lower the thermostat, as this causes the heating system to remain in its current "off" state for longer.
Television and radio
Most rabbinical authorities have prohibited watching television during Shabbat, even if the TV is turned on before the start of Shabbat, and its settings are not changed. However, most rabbis have permitted programming a device to record television programmes during Shabbat, the programming to be done before the start of Shabbat and the viewing after.
Most authorities also prohibit either turning on or listening to a radio. The reason is, although an electric current is not turned on, the radio makes a loud noise, falling under the Rabbinic prohibition of making noise with an instrument designed to make noise. However, it may be permitted to turn up the volume of a radio that is already on because many authorities permit adding to an electric current. Eliezer Waldenberg says that changing the station on a radio by using a dial[clarification needed] is prohibited, but Shlomo Auerbach says that it is permitted.
Regardless of permissibility, almost all authorities (including Conservative Nevins) consider that watching television, listening to a radio, or use of appliances for similar purposes on Shabbat violates the spirit of Shabbat and is not ideal.
Computers and similar appliances
In addition to possible halachic issues with any use of electricity, some additional issues may apply when using electronic devices such as computers.
Writing on the screen
Opinions differ regarding causing text to appear on an electronic screen (such as a computer screen or cellphone). Many argue that since the text will only appear on the screen for a short period, the Biblical prohibition on writing and erasing permanent text is not violated, so the action is only forbidden by rabbinic law. R' Shmuel Wosner was stricter, arguing that since text on the screen can last for a significant amount of time (i.e. an hour), it is considered "permanent" writing which is forbidden. However, other authorities say that even according to R' Wosner's approach, the Biblical prohibition would not apply if the device has a screensaver which automatically replaces the screen contents after a short period, or if the device is battery-powered (and not plugged in) and will inevitably run out of battery in not too long.
This judgment may be affected by the type of display used. For example, when using a CRT display (but not later types of display), words which appear on a computer screen are actually flickering many times a second; according to some authorities this means that such writing is not considered writing at all. On the other hand, text on an E Ink display (such as an Amazon Kindle) remains permanently even if the device loses electric power (unless the user decides to change the text), which makes it Biblically forbidden.
Writing to disk
Another issue is recording information on a computer (e.g. saving a file, or sending a text message which will be stored on a server or on the recipient's phone). Conservative Rabbi Daniel Nevins wrote that such recording violates the Biblical prohibition of writing. Among Orthodox authorities, opinions are divided on whether magnetic recording violates the prohibition of writing. In addition, R' Shlomo Zalman Auerbach argued that recording may violate a separate Biblical prohibition of "building", since one is creating the capability for the computer to show you this information later on.
It is also questionable whether the use of a keyboard or other input device to change what is displayed is a direct effect, as it depends both on the keyboard and on the device's pre-programmed behavior. Regarding printing a document on paper, some authorities view it as grama and only rabbinically prohibited (since the printing only occurs after some time and after the computer has calculated how best to print), while others view it as straightforward writing and thus Biblically prohibited.
The use of a computer might be considered "Uvdin d'Chol" (weekday/mundane activities), which are prohibited rabbinically to preserve the spirit of the sanctity of Shabbat, by preventing one from carrying out unrequired or grueling tasks and weekday-specific activities on Shabbat.
R' Nahum Rabinovitch ruled that soldiers (who need to write to save lives) should preferably use a pen with disappearing ink (which is rabbinically prohibited as the writing is temporary) rather than electronic writing on a computer, indicating what he saw as the seriousness of the prohibitions involved in using a computer.
The Shabbos App was a proposed Android app claimed by its creators to enable Jews to permissibly use a smartphone to text on Shabbat. Developers stated that the application would be released in December 2014, but the app was delayed and eventually never released. When announced, the app caused an uproar among the public, and many rabbis spoke out against the development.
Like other electrical appliances, telephones are bound by similar restrictions on Shabbat. Operating a telephone may involve separate prohibitions at each stage of the operation. Thus, removing a telephone from the receiver to produce a dial tone closes a circuit and makes a noise. Dialing closes more circuits and creates more noises. Speaking on the phone increases an existing current, but Shlomo Auerbach and many other authorities permit this. Hanging up the phone opens a circuit, which is a Biblical prohibition of "destroying" according to the Chazon Ish but a Rabbinic prohibition according to others.
Dialing on many phones, including cell phones, also causes the numbers to be written on a display screen, thus violating the prohibition of writing (as described above). If a phone call must be made on Shabbat, other factors being equal, it is preferable to use a phone without a display screen.
It is questionable if it is permissible to use an answering machine or voicemail to receive messages left during Shabbat, since one is benefiting from a violation of Shabbat, particularly if the caller is a Jew.
In an emergency case where a phone call must be made to save a life, making the phone call is permitted. In addition, a special phone has been invented to minimize the halachic issues regarding phone use on Shabbat; the inventors argue that its use by soldiers or other essential workers in less urgent situations is permitted. This phone is marketed as a "kosher phone" (unrelated to "kosher phones" in some other Jewish communities, which lack internet or media access to comply with bans on the internet in those communities).
There are varying views on the use of a microphone during Shabbat. While most Orthodox rabbinic authorities prohibit the use of microphones, there has been some argument for allowing the use of a microphone in a synagogue that is turned on before the start of Shabbat on the basis that a microphone does not create a human voice, but rather amplifies it. Those in the majority, who forbid the microphone, have various concerns, including the conduction of electricity that is affected by the human voice, and the attention that is drawn from the sound coming from the speakers.
A "Shabbat microphone" has been developed, which is intended to allow Rabbis or Hazzans to amplify and transmit their voice without affecting the electrical current of the microphone to hold congregations without violating Shabbat. It uses acousto-fluidic technology and constant electric current, so the sound source does not change the status of the electric current. It has not been approved by all Orthodox rabbinic authorities. Rabbis disagree about whether even a Shabbat microphone can be used when the sound is being recorded.
Washing clothes is not permitted on Shabbat, whether by hand or machine. Most rabbinical authorities have prohibited allowing a washing machine or dryer to run on Shabbat, even if it is set before the start of Shabbat. If the machine is still running after Shabbat starts when this was not planned, no benefit may be derived from clothes or other objects in the appliance during that Shabbat.
According to Orthodox authorities, while driving on Shabbat is prohibited directly because of the combustion of fuel, modern automobiles also have numerous electrical components whose operation is prohibited during Shabbat. These include headlamps and other external and internal lights, turn signals, and gauges. Additionally, the operation of the vehicle involves many uses of electricity and electrical circuits. According to many Conservative authorities, this use of electricity is not prohibited, and it may even be permitted to drive a car powered by an internal combustion engine in certain circumstances.
Operating an elevator is generally prohibited by Orthodox authorities for multiple reasons. However, Shabbat elevators have been designed automatically to travel from one floor to the next regardless of whether a human is riding the elevator or not, so many authorities permit the use of such elevators under certain circumstances. The environmental advantages of reducing energy consumption when the device is not in use are lost.
The use of automated surveillance systems has been reviewed. Examples include closed-circuit television, video cameras, and motion detectors. A person who walks within view of an operating surveillance camera may permit photography if the camera must be passed to enter a building or location and the photograph is not of direct benefit to the passerby. This is called a pesik reisha delo nicha leih (Aramaic: פסיק רישא דלא ניחא ליה, loose translation: "an inevitable resultant action that does not benefit the one who indirectly caused that action"). However, it is prohibited to knowingly walk past a motion sensor which switches on a light on Shabbat if the street or place is dark and because the turning on of the light substantively benefits the person, and it is a pesik reisha denicha leih (Aramaic: פסיק רישא דניחא ליה, loose translation: "an inevitable resultant action that does benefit the one who indirectly caused that action"). Observant Jews are advised to avoid walking past a motion sensor that they know is there and will switch on a light, or close their eyes when doing so.
Milking of cows
Some review articles have been published on the permissibility of milking cows on Shabbat using automated machines. Milking cows is fundamentally prohibited on Shabbat, but is permitted to relieve the suffering of an engorged cow, as long as the milk is allowed to go to waste rather than being stored.
Due to the desire that so much milk not go to waste, it was proposed to attach the pumping machine on Shabbat, to let the first few drops go to waste, then position a container to store the subsequent milk flow. While the Chazon Ish wrote that such a practice is forbidden, he is reported to have permitted it when asked orally, and some communities have used the practice accordingly. Using a device invented by the Zomet Institute in the 1980s, which allowed the switch from milking to waste to milking into containers to occur indirectly without human intervention, the act of milking cows became more indirect and thus more likely to be permitted. Yet another solution, whereby the cows are hooked up to the machine with electricity off, and the electricity is soon turned on automatically to milk the cows, was permitted in theory by the Chazon Ish and became practical in the late 20th century. It is currently practiced by the religious kibbutz at Sde Eliyahu.
Ways of circumventing the Shabbat prohibitions
Several innovations have been developed to address the needs of the Shabbat-observant user while not violating Shabbat.
In general, halacha permits a Jew to begin a Shabbat-violating action on Friday (before Shabbat) even though the action will be completed automatically on Shabbat. Therefore, the consensus of contemporary authorities permits a Jew to program a timer (referred to as a "Shabbat clock") before Shabbat to perform automatically a prohibited action on Shabbat. For example, it is permitted to attach a timer to a light switch on Friday afternoon so that the light will turn off late on Friday night when people wish to sleep, and will turn on again the next day when people are awake.
However, an exception to this rule may be the production of a noise which disturbs the peaceful environment of Shabbat, as shown by a debate in the Talmud over whether a Jew may add wheat on Friday to a water mill that will run automatically on Shabbat, because the addition of wheat to the mill will cause a loud noise. Rishonim disagree as to which opinion is normative. Joseph Caro in the Shulchan Aruch permits this action, but Moses Isserles (the Ramo) prohibits it absent great need. Accordingly, Rabbis Moses Feinstein and Shlomo Auerbach prohibit programming a radio to turn on during Shabbat, or allowing it to run on Shabbat, not because of the violation of electricity as such, but rather because the noise of the radio violates a separate prohibition.
Some authorities have raised other reasons to prohibit Shabbat clocks in general, but the consensus of many rabbis permits their use. Nowadays they are commonly used to manage lights in private homes, to operate dishwashers and milk cows in Shabbat-observant kibbutzim and moshavim, and for various purposes in public facilities such as hospitals and hotels.
Adjusting a Shabbat clock on Shabbat
Shabbat clocks are typically mechanical devices that are "programmed" by moving pegs that represent specific hours. One is permitted on Shabbat to move pegs on a mechanical device, but when the pegs are part of a Shabbat clock, the resulting activity (e.g. turning on a light) may be forbidden. Several different cases must be considered:
- Adjusting the shabbat clock so that a light turns on, sooner than it otherwise would have: This is forbidden, though some authorities are lenient in situations of need, since this can be considered turning on the light indirectly (grama).
- Adjusting the shabbat clock so that a light turns on, later than it otherwise would have: Nearly all authorities permit this, and the common practice is to permit it. However, if the adjustment is done by removing and reinserting a peg, the reinsertion could cause the light to turn on earlier relative to the state of no peg, which would likely be forbidden as previously discussed.
- Adjusting the shabbat clock so that a light turns off, sooner than it otherwise would have: This is similar to the case of turning the light on sooner, and thus forbidden. However, the act of turning off a light is less halachically serious than turning it on (a rabbinic rather than Biblical prohibition), so R' Shlomo Zalman Auerbach permits if the light (or other device) is of a type whose operation is only rabbinically forbidden, as the multiple layers of rabbinic prohibition create more grounds for leniency.
- Adjusting the shabbat clock so that a light turns off, later than it otherwise would have: This is similar to the case of turning the light on later, and thus permitted. (A minority of authorities hold it is forbidden due to causing more electricity to be consumed than would have otherwise.)
Other proposed bypasses
The KosherLamp, sold since 2004, is a lamp in which the electricity runs continually, but which contains a sliding cover so that the light can be exposed or blocked as desired. Thus, the lamp can be "turned on" or "turned off" even though in reality the bulb is always on.
In 2015, the KosherSwitch wall switch was introduced amid controversy, as a means of controlling electricity on-demand in a manner that is permissible according to several Orthodox authorities.
Use of electricity generated in Israeli power plants
Several review articles have been written about the permissibility of using electricity generated in Israeli power plants. In principle, it should be prohibited because one may not benefit from an action performed in violation of Shabbat. Thus, for example, if a Jew lights a candle in violation of Shabbat, both he and other Jews are forbidden to read a book using that candlelight. Similarly, if a Jew generates electricity in a power plant in violation of Shabbat, other Jews may not benefit from that electricity. However, there are several considerations to permit Jews to generate electricity in Israeli power plants and to use electricity generated in this manner.
The primary motive to permit generating electricity is pikuach nefesh (Hebrew: פיקוח נפש, "saving lives"). Electricity generated on Shabbat is needed for the day-to-day operations of hospitals, first aid centers, outpatients who require medical care in their homes, and climate control for people who need it, a refrigerator for a baby or the elderly who must eat refrigerated food, and possibly street lights which help prevent road accidents. Because it is impossible to distinguish between the electric current going to purposes recognised as pikuach nefesh and to other purposes, all electricity generation is classified as pikuach nefesh. The argument based on pikuach nefesh would allow a Jew to work at the power plant on Shabbat to generate electricity. Rabbis Shlomo Zalman Auerbach and Shlomo Goren permit this, but Auerbach and Moshe Feinstein question why non-Jews are not employed to do this work instead.
Assuming that a Jewish worker may generate electricity on Shabbat due to pikuach nefesh, opinions are divided on whether Jewish consumers may use this electricity for non-pikuach nefesh purposes. R' Shlomo Goren prohibits using it in ordinary circumstances using a Talmudic precedent: if meat is cooked for a patient who needs it for pikuach nefesh, nobody else may eat that meat, as this possibility could encourage the cook to prepare more meat than necessary, violating Shabbat without justification. However, R' Shlomo Auerbach, who permits the generation of electricity on Shabbat with some hesitation (see citation below), also permits the use of electricity based on a different Talmudic precedent: if a sick patient requires meat, and no dead meat is available, a live animal may be slaughtered (otherwise in violation of Shabbat) and its excess meat may be consumed by others on Shabbat. Since in this case, there is no way to cook any meat without slaughtering a whole animal, the rationale that the violator might do more than necessary does not hold.
Another possible reason for leniency is the fact that some Jewish power plant workers are unaware their work is considered Shabbat violation. Thus, it could be considered unintentional (Hebrew: שוגג, shogeg). When a person violates Shabbat unintentionally (as opposed to intentionally), some authorities permit other Jews to benefit from the violation. Thus, customers might be allowed to use electricity generated on Shabbat.
Nowadays, it is generally accepted that consumers may use electricity from the power plant. However, part of the charedi community refuses to use the electric grid (instead of running electricity generators at home), following the opinion of the Chazon Ish who argued that even if a power plant could run permissibly, using its electricity would be forbidden, as the secular workers there do not respect Shabbat and using their electricity would show public approval of their actions.
It is projected that in the future, when Israel's coal generating plants are shut down and replaced with natural gas power plants, it will be possible to run all-electric plants automatically without human intervention, removing the halachic questions about the use of this electricity on Shabbat.
Alternatives to publicly generated electricity
Tens of thousands of Israeli haredim, forming a significant fraction of the Haredi population, run private electric generators to avoid using the public electricity supply on Shabbat. Some[who?] even refuse to use a generator because the end-product of electricity is indistinguishable from what is provided to ordinary consumers, so using electricity in any manner constitutes the appearance of violating Halakhah. Some of these people[who?] use a kerosene lamp that provides them with a minimal amount of light, and some use only Shabbat candles for Friday night dinner.
Some people who do not use electricity also do not use faucets or other mechanisms that provide water from public supplies, because the municipal water pumps are operated electrically. These people prepare containers of water on Friday sufficient to provide for their needs on Shabbat.
- Broyde and Jachter, part II, section G.
- Neulander, Arthur. "The Use of Electricity on the Sabbath." Proceedings of the Rabbinical Assembly 14 (1950) 165–171.
- Adler, Morris; Agus, Jacob; and Friedman, Theodore. "Responsum on the Sabbath." Proceedings of the Rabbinical Assembly 14 (1950), 112–137.
- Klein, Isaac. A Guide to Jewish Religious Practice. The Jewish Theological Seminary of America: New York, 1979.
- Daniel Nevins, The Use of Electrical and Electronic Devices on Shabbat
- Rabbi Michael Broyde & Rabbi Howard Jachter, The Use of Electricity on Shabbat and Yom Tov, part 1, section A. Journal of Halacha & Contemporary Society No. XXI – Spring 1991 – Pesach 5751.
- Comments to Mishneh Torah, Laws of Shabbat 12:1
- Shabbat 41a.
- Shabbat 41b
- Yevamot 6b
- Shlomo Zalman Auerbach, Minchat Shlomo p. 111
- Beitzah 23a
- Rashi to Beitzah 23a
- Beit Yitzchak, Yoreh Deah 2:31
- Broyde and Jachter, part II, section A.
- What’s Wrong With Texting on Shabbat? A Halachic Analysis
- Chazon Ish, Orach Chaim 50:9
- Broyde and Jachter, part II, section B
- מא. העדפת כתיבה ב"עט שבת" על פני כתיבה במחשב
- Chazon Ish, Orach Chain, 50:9
- Broyde and Jachter, part II, section C.
- Rav Asher Weiss’ New Perspective on the Use of Electricity on Shabbat – Part Two by Rabbi Chaim Jachter
- Mavir (8) – Yetzirat Nitzotzot Hashmal Stati VeOd
- Broyde and Jachter, part II, section D.
- Surely You're Joking, Mr. Feynman!: Adventures of a Curious Character, chapter Is electricity fire?, Richard Feynman, Ralph Leighton (contributor), Edward Hutchings (editor), 1985, W W Norton, ISBN 0-393-01921-7, 1997 paperback: ISBN 0-393-31604-1 
- Broyde and Jachter, part II, section E.
- Chazon Ish, Orach Chaim 50:9
- Minchat Shlomo, p. 107
- Broyde and Jachter, part II, section F.
- Minchas Shlomo, Chapter 10; Broyde and Jachter, part IV, section A.
- Rabbi Chaim Jachter, Opening Refrigerators on Shabbat
- Broyde and Jachter, footnote 59.
- Gorman, Carma R. (2009). "Religion on Demand: Faith-based Design". Design and Culture. 1 (1): 9–22. doi:10.2752/175470709787375715. S2CID 143513427.
- Fasman, Jon (March–April 2006). "Trying to Keep the Sabbath Wholly". I.D.
- Peninei Halakha – 06. Timers
- Jachter and Broyde, part IV, section C.
- Rabbis Shlomo Zalman Auerbach (Shulchan Shlomo 340:11), Moshe Feinstein, and Dov Lior
- Shevet haLevi 6:37, bringing the example of writing on one's body which is Biblically forbidden (Shabbat 104b)
- Rav Gedalyah Rabinowitz Halachah Urefu'ah (volume V)
- Reading a Kindle on Shabbat
- Shemirat Shabbat Kehilchata, chapter 66 footnote 211
- Hannah Dreyfus (2 October 2014). "New Shabbos App Creates Uproar Among Orthodox Circles". The Jewish Week. Archived from the original on 7 October 2014. Retrieved 12 October 2014.
- David Shamah (2 October 2014). "App lets Jewish kids text on Sabbath – and stay in the fold; The 'Shabbos App' is generating controversy in the Jewish community — and a monumental on-line discussion of Jewish law". The Times of Israel. Retrieved 3 October 2014.
- Daniel Koren (2 October 2014). "Finally, Now You Can Text on Saturdays Thanks to New 'Shabbos App'". Shalom Life. Archived from the original on 7 October 2014. Retrieved 12 October 2014.
- "Will the Shabbos App Change Jewish Life, Raise Rabbinic Ire, or Both?". Jewish Business News. 2 October 2014. Retrieved 12 October 2014.
- "Why We Cancelled Our Kickstarter Campaign". Shabbos App. 22 October 2014. Archived from the original on 21 October 2014. Retrieved 22 October 2014.
- Erik Schechter (3 October 2014). "Shabbos App for Sabbath Texting Roils Rabbis". Popular Mechanics. Retrieved 13 October 2014.
- Broyde and Jachter, part IV, section B.
- J. David Bleich. Contemporary Halachic Problems, volume 5, pages 157–170.
- "Introducing: A 'Kosher Phone' Permitted on Shabbat". Israel National News.
- Bleich, J. David (30 September 1977). Contemporary Halakhic Problems. KTAV Publishing House, Inc. p. 231 – via Internet Archive.
- "Acousto-Fluidic Sound Augmentation for Orthodox Jewish Worship Spaces". Archived from the original on 23 February 2005. Retrieved 23 February 2005.
- On Recording Shabbat and Yom Tov Services
- J. David Bleich, Contemporary Halakhic Problems, volume 5, pages 129–156.
- Bleich, ibid.
- Ribiat, loc. cit.
- Broyde and Jachter, part IV, section D.
- Howard Jachter and Ezra Frazer, Gray Matter, volume 1, pages 201–214.
- Techumin 15:394–410, cited in Jachter and Frazer 1:213.
- Due to mefareik (Hebrew: מפרק), a subcategory of dash (Hebrew: דש threshing); Shabbat 95a, cited in Jachter and Frazer 1:200.
- R' Abraham Isaac Kook permitted dairy farmers to ask a non-Jew to milk the cow, in accordance with a medieval ruling by Maharam of Rothenburg. Although milking a cow is a Biblical prohibition, asking a non-Jew to perform a prohibited act on Shabbat is only a Rabbinic prohibition, so to alleviate the animal's pain it is permitted (Jachter and Frazer 1:202). On religious kibbutzim in Israel where only Jews live, it may not be practical to ask non-Jews to milk the cows. Rav Kook, acknowledging this reality in his time, and the Chazon Ish permitted milking a cow and allowing the milk to be wasted because this too is only a Rabbinic prohibition and can be permitted because of the mitigating factor to prevent the cow from feeling pain (Jachter and Frazer 1:204).
- Haim Navon, National Law: Class 21, Milking on Shabbat
- Jachter and Frazer 1:206-9.
- Jachter and Frazer 1:210–214.
- Shabbat 17b-18a; Mishneh Torah, Laws of Shabbat 3:1; Shulchan Aruch Orach Haim 252:1
- Torah Musings, Timers on Shabbat and Yom Tov
- Shabbat 18a
- Broyde and Jachter, section V, part A.
- Peninei Halakha: Timers
- Broyde and Jachter, part V, section B.
- "New York – Shedding Light on KosherSwitch". www.vosizneias.com.
- "Endorsements/Blessings « KosherSwitch -Control Electricity on Shabbat!". www.kosherswitch.com.
- "Responsa « KosherSwitch -Control Electricity on Shabbat!". www.kosherswitch.com.
- Howard Jachter and Ezra Frazer, Gray Matter, volume 2, pages 54–66; Levi Yitzchak Halperin, Teshuvot Ma'aseh Chosheiv 1:31, and Yisrael Rozen, Techumin 16:36–50 (cited in Jachter and Frazer 2:55).
- Teshuvot Minchat Shlomo 2:15 and Tinyana 24. Cited in Jachter and Frazer 2:56.
- Meishiv Milchamah 1:366–385. Cited in Jachter and Frazer 2:56.
- Teshuvot Igrot Moshe (Orach Chaim 4:127). Cited in Jachter and Frazer 2:56.
- Cited in Jachter and Frazer 2:56–57.
- שימוש בחשמל בשבת
- Tahanat Koach Hashmalit beShabbat
- 05. Using Electricity that Was Produced on Shabbat
- חשמל בשבת
- לא הכל "כשר" בגנרטורים של החרדים
- Michael Broyde and Howard Jachter (Pesach 1991). The Use of Electricity on Shabbat and Yom Tov. Journal of Halacha & Contemporary Society, No. XXI. Retrieved on 2008-05-16.
- Encyclopedia Talmudit, "Electricity" 18:155–190.
- Dovid Ribiat. The 39 Melochos: An Elucidation of the 39 Melochos from Concept to Practical Application. Nanuet, N.Y. : Feldheim Publishers, 1999. Volume 4, pages 1201ff.
- Rabbi Hayim Halevy Donin. To Be a Jew, A Guide to Jewish Observance in Contemporary Life, Basic Books, 1972, 1991, ISBN 0-465-08624-1, pages 89–93