The Prohibition of Turning On an Incandescent Bulb On Shabbat and Yom Tov by Rabbi Chaim Jachter


Poskim today assume that turning on an electric appliance in which a filament is heated until it glows on Shabbat constitutes a violation of Torah law.  Although there is great debate whether completing a circuit in such an appliance in which a filament is not heated until it glows is a Biblical or Rabbinic level prohibition, a clear consensus has emerged concluding that turning on an appliance with a glowing filament violates a Torah prohibition.  In this essay we will explore the basis and development of this consensus view.

Four Sources in the Gemara

There are four passages in the Gemara which discuss heating metal on Shabbat.  The Gemera, (Yevamot 6b)  states that melting metal on Shabbat in preparation for use in administering the form of capital punishment known as Sereifah (burning) involves two violations of the laws of Shabbat.  The two violations are cooking (Mevashel) and burning (Havarah).  Teshuvot Avnei Neizer (Orach Chaim 229) asserts that this Talmudic passage is the primary source that teaches that one who heats a metal violates a Torah level prohibition.  The second source is the Gemara on Pesachim 75a which records a dispute between Rav Chisda and Ravina whether a Gachelet Shel Matechet (a burning metal coal) is defined by the Halachah as fire.

The Gemara in Yoma 34b relates that if the Kohen Gadol (High Temple Priest) found it difficult to immerse in a cold Mikvah, iron bars were heated prior to Yom Kippur and placed into the Mikvah used by the Kohein Gadol.  The Maggid Mishneh (commenting on Rambam Hilchot Shabbat 12:1) points out that we see from this Gemara that heating a metal involves violating a Biblical level prohibition.  Had the Gemara regarded heating a metal as only a rabbinic level prohibition, it would have permitted heating the metal rods on Yom Kippur.  This is because of the celebrated rule "Ein Shevut BeMikdash," rabbinic prohibitions do not apply in the Beit HaMikdash (Temple).

Nonetheless, the Maggid Mishnah's proof is not beyond dispute.  The counter argument is that indeed heating metals is merely a rabbinic level prohibition, but nevertheless we do whatever is necessary to minimize violating rabbinic prohibitions even in the Beit Hamikdash. (The following sources support this contention: Eruvin 103a, Rambam Hilchot Korban Pesach 1:18, and the commentary ad. loc. of the Lechem Mishneh.)

The fourth passage is Shabbat 74b which defines heating a metal to soften it as an act of Bishul.

Rishonim and Acharonim

Rambam (Hilchot Shabbat 9:6) rules that heating a metal constitutes a Toladah (subcategory) of the Melachah (prohibited act of work) of cooking.  In Hilchot Shabbat 12:1 Rambam rules that heating a metal is a Toladah of the Melachah of Havarah.  Raavad (commenting on the Rambam Hilchot Shabbat 12:1) asserts that the act of heating a metal is considered only Bishul.  The Avnei Neizer (O.C. 229) explains that the Rambam and Raavad disagree as to whether the Halacha follows Rav Chisda or Ravina in their debate on Pesachim 75a as to whether a Gachelet Shel Matechet constitutes a fire. The Raavad rules that a heated metal is not considered fire. Rav Shlomo Zalman Auerbach (Teshuvot Minchat Shlomo 1:105-107) disputes this interpretation and offers an alternative interpretation.  Halacha accepts the opinion of the Rambam as normative (Chayei Adam 45:2 and Sha’ar Hatziyun 318:1).

The Chazon Ish (O. C. 50:9) and Rav Shlomo Zalman Auerbach (Minchat Shlomo 1:107) disagree about the temperature at which one violates the prohibition of heating a metal.  The Chazon Ish rules that the violation occurs at the point that the metal becomes Yad Soledet Bo (hot to the extent that one’s hand would recoil when touching it).  Rav Shlomo Zalman argues that the heating of metal is Halachically insignificant until the metal heated to the point that it appears as a glowing coal.  Rav Moshe Feinstein (Teshuvot Igrot Moshe O.C. 1:93) concurs with Rav Shlomo Zalman. 

Rambam appears to contradict himself as to whether heating a metal constitutes Bishul or Havarah. In Hilchot Shabbat 12:1 Rambam writes that it constitutes Havarah and in Hilchot Shabbat 9:6 he states that it is Bishul.  The Lechem Mishneh (commenting on Hilchot Shabbat 12:1) explains that one violates different prohibitions depending on the stage of the process of heating metal which has been reached.  Bishul is violated at the temperature at which the metal can be softened.  At the point that metal can be tempered, Havarah is violated.  The Lechem Mishneh's approach to this problem is accepted (Shaar HaTziyun 318:1 and Teshuvot Tzitz Eliezer 3:17) though the Chazon Ish (O.C. 50:9) presents a very different way to resolve this apparent contradiction in Rambam. 

Incandescent Lamps

When the incandescent bulb (which is essentially a glowing metal caused by the resistance in the wire to the electric current flowing through it) was introduced during the latter part of the nineteenth century, Poskim argued whether lighting such bulbs constitutes an act of Bishul or Havarah.  Teshuvot Maharsham (2:246) suggests that lighting an incandescent bulb was only a rabbinic prohibition, due to the dissimilarity between an incandescent bulb and the fire created in the Mishkan.  He noted that the incandescent bulb more resembled the Biblical burning bush (fire that does not consume) than the fire in the Mishkan.  Rav Eliezer Waldenberg (Tzitz Eliezer 1:20:6) vigorously refutes the Maharsham's suggestion.  The fact that Rambam's opinion that heating a metal until it glows violates Havarah clearly indicates that a glowing metal constitutes a fire.  Poskim reject the suggestion of the Maharsham.  Both the Tchebiner Rav (Teshuvot Doveiv Meisharim 1:87) and Rav Ovadia Yosef (Teshuvot Yabia Omer O.C. 1:19) assert that the Maharsham's suggestion cannot be utilized even as a Senif LeHakel, a component in a lenient ruling. 

The Chazon Ish (O.C. 50:9) writes that since the wires in an incandescent bulb are heated, turning on an incandescent bulb constitutes an act of Bishul.  Rav Shlomo Zalman Auerbach, however, notes that one does not care that the metal within the bulb is softened and that one does not perceive the softening of the metal within the lamp.  Moreover, the metal returns to its original state immediately when the light is extinguished. Thus, argues Rav Shlomo Zalman, the Halacha attaches no significance to the fact that the metal is softened.  Thus, lighting an incandescent bulb is not considered to be an act of Bishul.  Rav Moshe Feinstein presents a somewhat similar argument to that of Rav Shlomo Zalman Auerbach (Teshuvot Igrot Moshe O.C. 3:50).

Most authorities agree with Rav Shlomo Zalman (1:12) that turning on an incandescent bulb is considered to be an act of Havarah.  Rav David Tzvi Hoffman (Teshuvot Melamed Lehoil 1:49) states what has emerged as the consensus opinion - “Havarah refers to the creation of light and not the burning of fuel.”  Almost all authorities find the analogy between an incandescent bulb and the Rambam's heated metal to be compelling.  Teshuvot Achiezer (3:60), Teshuvot Tzitz Eliezer (1:20:8), Teshuvot Mishpetei Uzziel (II O.C. 36), and Teshuvot Beit Yitzchak (Y.D. 1:120) are some of the other major authorities who rule that causing a filament to glow constitutes an act of Havarah.

It is related by many (including Rav Yosef Dov Soloveitchik) that Rav Chaim Ozer Grodzinski (the preeminent Halachic authority of pre-World War 2 European Jewry) used to routinely use an incandescent bulb for the fire of Havdalah.  He did so in order to emphasize to all that an incandescent light constitutes a fire.  On the other hand, there is great debate as to whether a Biblical or rabbinic prohibition is violated if one turns on an appliance in which a glowing filament is not present (see Chazon Ish O.C. 50:9 and Teshuvot Minchat Shlomo 1:11). 

Lighting an Incandescent Bulb on Yom Tov

The Mishnah (Beitzah 4:7) teaches the well-known rule that although one may transfer fire on Yom Tov, it is forbidden to light a fire on Yom Tov.  Poskim debate whether this constitutes a Biblical or rabbinic prohibition (see Beiur Halachah 502:1 s.v. Ein Motziin).  When incandescent bulbs were first introduced a few prominent Poskim permitted lighting an incandescent bulb on Yom Tov, arguing that lighting an incandescent bulb constitutes a transfer of fire rather than starting a fire (Encyclopedia Talmudit 18:178).  This approach, however, is rejected by the overwhelming majority of authorities primarily because it emerges from a mistaken understanding of how an incandescent bulb works.  Those who permitted this lighting thought that the flow of electrons in the filament is what causes the bulb to glow.  They believed that when one completes a circuit, the electrons in the filament then have a path in which to flow and thereby cause a glow.  According to this understanding, one is simply transferring the electrons when turning on a light.  Rav Shlomo Zalman Auerbach (Teshuvot Minchat Shlomo 1:9 footnote 5), however, notes that this is an erroneous understanding of how an incandescent bulb operates.  The glow does not result from the flow of electrons but rather from the resistance in the wire to the flow of the electrons in the filament.  Thus, one clearly creates fire when turning on an incandescent bulb and is forbidden on Yom Tov.  Although some may remember a time when some Rabbanim actually permitted lighting an incandescent bulb on Yom Tov, the accepted opinion in the past century has been to forbid turning on lights on Yom Tov.  Rav Shlomo Zalman Auerbach develops this point at great length in his seminal work on electricity known as Meorei Eish (chapters 1-3).  Among the many authorities who stated that turning on an incandescent light is forbidden on Yom Tov are Chazon Ish (ad. loc.), Teshuvot Chelkat Yaakov (1:51), Teshuvot Melamed Lehoil (ad. loc.), and Teshuvot Yabia Omer (O.C. 1:19).

Next week we shall review the question as to whether turning on an electric appliance where no filament is heated constitutes a Torah level or rabbinic level prohibition.   

Electricity without a Heated Filament By Rabbi Chaim Jachter

Showering on Yom Tov by Rabbi Chaim Jachter