Mishmeres HaShabbos has received a wave of inquiries from the public in response to a letter Gedolei Yisroel shlita issued warning the public about innovations in various devices and appliances that might be prohibited for use on Shabbos.
"We hereby announce to the public," reads the letter, dated 26 Kislev and signed by HaRav Eliashiv, HaRav Shteinman, HaRav Shmuel Halevi Wosner, HaRav Nissim Karelitz, HaRav Chaim Kanievsky and HaRav Shmuel Auerbach shlita, "that electronic devices whose use activates or increases the electrical current or digital notations, and the like, are prohibited on Shabbos.
"One must beware not to rely on contrived heteirim based on sofek psik reisha or grommo which are highly questionable. And in the merit of keeping Shabbos, may we be redeemed very swiftly."
Awareness of the problem was raised following an investigative report several months ago about various contemporary problems that have arisen including the use of state-of-the-art refrigerators, water pumps in tall buildings and other electrical devices that entail Shabbos violations.
Recently we conducted an extended conversation with Mishmeres HaShabbos heads HaRav Yitzchak Darzi and HaRav Eliyohu Beifus regarding many technological developments in recent years that involve increasing or decreasing the electrical current, the use of electronic chips, digital impulses, etc.
The issue comes up on a day-to-day basis, though most of the public is wholly unaware any Shabbos prohibition is involved. Today tall buildings, for instance, are often equipped with pumps designed to increase the water pressure. The pumps are activated whenever the tap is opened and deactivated when it is closed. But because the pumps are installed in the basement of the building the residents see only a regular faucet and the halachic question never comes to mind. Were the pump installed under the sink itself, for example, they would see the effect and immediately realize that opening and closing the tap on Shabbos is a real problem.
To solve the problem, today a special device can be installed to ensure that opening the tap does not engage the pump. Instead, the water pressure remains constant and the faucet releases the flow of water back to a tank if the water pressure rises as a result of low usage. Without the device, turning on the faucet entails chilul Shabbos.
Another example is the refrigerator. Today digital refrigerators are taking over the market. Since the range of models is very broad, each has various features, but what they all share in common is that every refrigerator has a digital card that functions like a computer serving as a control center. It goes without saying that the card operates through electrical circuits that constantly open and close — not by bringing wires together physically, but through semiconductors, which close the circuit by transforming a substance into a conductor, which gedolei Yisroel shlita have ruled is prohibited on Shabbos. These control centers are very sensitive and they respond to actions of users of the equipment.
The more technology advances, the greater the perils, and the leading poskim are called on to address previously unknown questions.
Another issue that is almost unknown to the general public relates to air conditioners labeled with an "inverter" tag, which signifies savings in electricity consumption. The basic concept of an inverter motor is a change in the electrical current.
The standard electrical current is at a frequency that changes from positive to negative 50 times per second (alternating current), but the amount of current in the device at any given moment (amperes), and therefore the power of the motor, is fixed. Inverter motors, on the other hand, have a special apparatus that switches the alternating current to direct current, and a control mechanism that allows it to provide a lot of power one moment, and very little the next. This allows it to run more efficiently since it can deliver more power when necessary without running all the time at high power.
When the air conditioner is turned on, it works at full capacity and when it senses it will soon reach the desired temperature it lowers the power slightly. If the room heats up it increases its capacity, thereby balancing itself until it reaches the right capacity to maintain the desired room temperature.
Since the thermostat in this type of air conditioner does not turn it on and off, but merely strengthens or weakens the current, there were those who claimed it poses less of a problem on Shabbos than a regular air conditioner, but according to the rabbonim, boosting the current is prohibited as well. In fact, this type of air conditioner is worse in a way: Because the whole aim of this air conditioner is to precisely balance the temperature, its sensors are highly attuned to the slightest change in the room and they respond immediately. According to the manufacturer, opening a door or window has an affect within 30-120 seconds, and changes in closer proximity to the air conditioner can have an even faster effect.
When this information was presented to HaRav Eliashiv, HaRav Shteinman and HaRav Karelitz, they held this may well not be considered grommo, but rather a deliberate action (maaseh beyodayim). This problem (along with problems with standard air conditioners) can be overcome simply by disengaging the thermostat on Shabbos.
Other examples include hotels where the air conditioners are activated or deactivated when a window is opened in the room, or pressure sensors that activate the air conditioner when someone steps into the room. This problem can be solved in some hotels, but the guest must ask in advance that the sensor system be turned off.
Likewise, at the drink bar is a weighing device that notifies the hotel computer system if drinks were taken from the bar, even if they are later returned from a purchase at a nearby kiosk.
Most of the problems mentioned above can be solved quite simply, such as a resistor for inverter air conditioners. The same technology that created the problem and the halachic issues can also be called on to provide solutions.
When the public begins to demand devices that are permitted by halacha and manufacturers become aware of the demand, they will find a way to produce kosher devices of their own accord. For instance, when the public began to demand a refrigerator with a proper Shabbos mode, Amcor manufactured a special model under the supervision of HaRav Mordechai Gross that accords with halacha according to all rabbonim.
To contact Mishmeres HaShabbos call 072-216-4422 or 057-319-1060 from 7:00 p.m. to 11:00 p.m.