Q. May I plug during Shabbos a cooking appliance into an
outlet that is now not powered but will be turned on by a timer later on?
A.Horav Shlomo
Miller’s Shlit”a opinion is that it is prohibited since it is a P’sik Reisha
Denicha Lei, or an inevitable act that one desires. He would prohibit this in
Yom Tov too.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a