Question: Is there any difference between Shabbos and Yom Tov with regard to using electricity?
Discussion: Turning electric devices on or off is prohibited on Yom Tov. In a general sense, this can be divided into two separate categories: Turning on an incandescent light bulb, and turning on other electrical appliances which do not involve lighting a bulb.
Turning on an incandescent bulb involves the melachah of mav’ir, kindling a fire. Although this melachah is permitted on Yom Tov for the sake of a Yom Tov need, it is prohibited to create a new fire. Turning on an incandescent bulb does, indeed, constitute creating a new fire and is therefore prohibited on Yom Tov.89
Aside from the issue of mavir when lighting an incandescent bulb, there are a number of other reasons why lighting an incandescent bulb – and why using any electrical device on Shabbos – is generally accepted as being prohibited. These include:
A concern for the melachos of boneh (building)90 or makkeh bepatish (finishing)91 when completing an electrical circuit.
Molid (creating something new).92
A general violation of the spirit of Shabbos.
With regard to all of these issues, there is no difference between Shabbos and Yom Tov, as none of them are permitted for the sake of ochel nefesh.
It is permitted, however, to leave a standard electric burner on from before Yom Tov and cook on it during Yom Tov. Induction cooktops, though, are prohibited, because they use electricity to create a magnetic field that heats the bottom of the pot. Even if left on from before Yom Tov, the unit reacts to the pot being placed on, or removed from, the cooking surface.93 However, it is permitted to leave food in a pot on an induction cooktop from before Shabbos or Yom Tov with a timer set to shut off the electricity, allowing one to remove the pot after the electricity goes off.94
Question: I have the air-conditioner on a timer (known as a Shabbos clock) set to go on later during the day. However, it became unexpectedly hot. Can I change the settings of my time switch to make it go on earlier?
Discussion: Grama, causing melachah to be done indirectly, is treated more leniently on Yom Tov than on Shabbos.95 According to R’ Shlomo Zalman Auerbach, changing a manual Shabbos clock to go on earlier or later is considered to be grama. Therefore, he permitted changing the setting on a manual Shabbos clock (on Yom Tov) to make it go on earlier. However, it is unclear whether he would permit causing it to go off earlier.96
Many Poskim, though, feel that changing the setting of a Shabbos clock should not be considered grama and is instead tantamount to directly turning the electricity on and off.97 Accordingly, it would be prohibited to change the settings even on Yom Tov.
According to some Poskim, delaying the air-conditioner from turning on or off is permitted on both Shabbos and Yom Tov. This is not considered grama since one is not causing the air-conditioner to go on or off but rather to stay as it is for longer.98 Others, however, prohibit making any changes to a time switch.99
Note that the halachos of Shabbos and Yom Tov concerning electricity and electronics are complex, especially since these technologies were not addressed by Poskim until recently. This is compounded by the fact that new technology is constantly being developed and this might change the halachic status of any particular device. Therefore, a competent halachic authority should always be consulted before assuming anything to be permitted.
89 See Igros Moshe I:115. When electricity had been recently discovered and was little understood, there were some Poskim who permitted using it on Yom Tov. They were led to understand that “fire” was actually present within the electrical wires, and so turning on an electric light involved simply bringing the fire out of the wires and into the bulb. Since no new fire was being created, they ruled that this should be permitted on Yom Tov. Of course, as we now know, this is not an accurate depiction – instead, when an incandescent bulb is lit, a new flame is being created. Therefore, the consensus of Poskim today is that lighting an electric light is prohibited on Yom Tov.
90 Chazon Ish, Orach Chaim 50:9.
91 Tzitz Eliezer VI:6; Minchas Asher I:30; see also ibid. II:34.
92 Beis Yitzchak II:31.
93 See Minchas Ish, Shabbos II, page 499, regarding Shabbos. Since this is based on the usage of electricity which is prohibited on Yom Tov, the same would apply on Yom Tov.
94 Ibid.
95 See Sha’ar Hatziyun 514, note 31.
96 Shemiras Shabbos Kehilchasah 13:31 and footnotes 109 and 110; see there for discussion and background. The reason for the distinction is that creating a new flame (turning on) is prohibited only rabbinically (since kindling is permitted on Yom Tov) and is therefore treated more leniently. The melachah of mechabeh (turning off), however, is Biblically prohibited on Yom Tov except under certain circumstances. [Apparently, this would apply only to electricity which turns on a fire, such as an incandescent bulb. Therefore, air-conditioners, which do not burn a fire, should be permitted either way. However, the above source does not distinguish between different uses of a time-clock.]
97 Igros Moshe, Yoreh Deah III:47:4; ibid., Orach Chaim IV:91:5; Shevus Yitzchak, Inyanei Grama 16. See also Orchos Shabbos 29, footnotes 26-27 for a lengthy discussion of the two opinions.
98 Orchos Shabbos 29:9.
99 Igros Moshe ibid.; Orchos Shabbos 29:9 citing Chazon Ish.