Hacham Bension Abba Shaul (Israel, 1923-1998), in his work Or Le’sion (vol. 2, 36:16), addresses the Halachic status of food prepared by machines in factories run by non-Jews. In these factories, a worker presses the button which activates the conveyor belt. The food products are then automatically moved into a cooker and then packaged. The entire process happens automatically, with the only human involvement being the press of a button. The question arises whether pressing the button suffices to render the food forbidden as "Bishul Akum" – food cooked by gentiles, or if this food should be permissible by virtue of the fact that it was cooked not by a person, but rather by an electric current.
Hacham Bension rules that while the initial surge of electrical energy is attributed to the person who pressed the button, the rest of the process is considered to have been done automatically, on its own, and not by a human being ("Ma’aseh Kof Be’alma"). Therefore, any food that is cooked by force of the initial surge of energy is considered "Bishul Akum" and forbidden for consumption. All food produced subsequently, however, is permissible, as it considered to have been produced by a machine, and not by a non-Jewish person.
This perspective on electricity also affects the situation of an ill patient for whom food must be cooked on Shabbat. If a person is gravely ill, Heaven forbid, and requires freshly-cooked food on Shabbat, it is, of course, permissible to cook food for him, as the concern for saving a human life overrides the prohibition against cooking on Shabbat. However, Hacham Bension rules that when possible, it would be preferable to cook the food via electricity, such as with an electric oven, as opposed to a gas stove, for example. Since only the initial surge of electricity is attributed to the person, one is not considered to have actually cooked the food. And thus, although there may be other Shabbat violations entailed in the process, one can at least avoid the Torah prohibition of cooking by using an electric cooking device. Hence, assuming one is able to do so without posing any danger to the patient, one should cook the food with an electric device.
Another application of this theory is the issue of Shabbat candles. Hacham Bension rules that one cannot fulfill the Misva of Shabbat candles by turning on electric lights, because we consider one who turns on the switch to be kindling the light only for the first moment. After that moment, the light is seen as burning on its own. Hence, turning on an electric light is Halachically equivalent to lighting a candle with just a tiny drop of oil, which obviously will not burn for more than just a brief moment. Just as one cannot fulfill his obligation by lighting such a candle, one likewise cannot fulfill the obligation by turning on an electric light. On this basis, Hacham Bension answers the question of how women recite a Beracha when lighting the Shabbat candles nowadays, when the room is already fully illuminated with electric lights. As the room is fully lit, the Shabbat candles do not add any significant amount of light, and it would thus seem that this does not fulfill any Misva. Hacham Bension explains that since the electric lights do not suffice for the Misva of Shabbat candles, one must light the candles in order to fulfill the Misva, and thus a Beracha is recited over the lighting. (This discussion appears in the work Ner Le’sion, starting on p. 386.)
It should be noted that Hacham Ovadia Yosef disagrees with Hacham Bension on this final point. In his view, one can, in principle, fulfill the Misva of Shabbat candles through electric illumination, despite the fact that it is, of course, customary to light candles. As for the question of how one can recite a Beracha when lighting in an illuminated room, Hacham Ovadia writes that it is preferable for the woman to first turn off the lights in the room, and then light the Shabbat candles with the intention not to accept the onset of Shabbat. She should then turn the lights back on and accept Shabbat. Alternatively, she may accept the onset of Shabbat at the time of lighting, and then have somebody who had not yet accepted Shabbat turn the lights back on.
Summary: If a gravely ill patient needs food cooked for him on Shabbat, it is preferable to cook the food via electricity, as opposed to fire. According to some opinions, before lighting Shabbat candles one should first turn off the electric lights in the room, and then have them turned on after candle lighting.
