Do we rely on a glow bar to make bread be considered Pas Yisroel, or does it need to be done with a pilot?
Does a separate heating element (of about 500 degrees) which is added to a oven make the bread Pas Yisroel?
There is a debate among contemporary kashrus agencies and their respective Poskim whether a glow plug lit by a Jew suffices for Pas Yisroel or not.
While those in support of the glow plug compare it to throwing in a twig to the fire, which is considered as though one has participated in the baking, others challenge this comparison on several accounts.
The twig forms parts of the fire; the glow plug is a disparate entity. In other words, since the glow plug isn’t near the fire it cannot be considered like a twig thrown into the fire.
The purpose of the twig is to hasten and aid the cooking process; the glow plug has zero or insignificant effect on the cooking.
The twig would be thrown in daily whereas the glow plug is placed in the oven only once. It is argued that the throwing of the twig is effective only for the first heating of the oven occurring at the time.
Others argue that the participation of a twig is only effective after the fire is burning; the glow plug is turned on before the oven is lit. According to most poskim, however, the participation of the Jew can happen even before the fire has been lit.
Contemporary glow plugs usually contain heating elements of 500 degrees or higher which has a noticeable effect on the heating.
Halachically, there is strong room to allow the glow plug to suffice as Pas Yisroel despite the arguments mentioned earlier. However, since there are different opinions on the matter, one may wish to be stringent.
ראה בכ״ז קובץ מסורה ח ע׳ צג. המתיבתא תשס״ט. ועוד.