Can one daven Mincha close to shkiyah on Erev Shabos or does one have to accept tosefes Shabos before the shkiyah. What is the shiur of tosefes Shabos for a man.
Answer:
Tosefes Shabbos must be accepted before shkiyah.
The best way to do this is to complete mincha in advance of shkiyah, and to accept tosefes Shabbos after completing mincha.
The Rosh writes that a “monetary” tosefes is not sufficient, but does not write how long the time is. The Mishnah Berurah (261:22-23) writes that one should preferably accept Shabbos 15 minutes before shkiyah (or half an hour if possible), but the Iggros Moshe and others write that a few minutes are sufficient.
The Mishnah Berurah (261:21) writes that Shabbos should be accepted by speech (“I hereby accept upon myself the holiness of Shabbos”).
However, if one sees that he won’t have enough time after minchah to accept Shabbos, Shabbos should be accepted by thought alone (an acceptance of Shabbos to refrain from labor), and mincha can then be davened (this ruling is given by the Machazeh Eliyahu).
Best wishes.
