From the time one accepts tosefet Shabbat, he must refrain from all melakhot forbidden by Torah law. Rabbinically prohibited actions are also forbidden at this point, unless the melakha to be done is for a mitzva, for a Shabbat need, or for some other great need, because in such situations the Sages did not intend for their prohibitions to apply. For example, if one forgot to tithe produce and wishes to eat it on Shabbat, he may tithe it even if he has already accepted Shabbat, because tithing produce on Shabbat is only prohibited rabbinically.
One who has already accepted tosefet Shabbat may ask a fellow Jew who has yet to accept Shabbat to do melakha on his behalf. Women generally light candles and accept Shabbat at the time listed on calendars. Men, in contrast, go to shul to pray the weekday Minĥa (which usually begins shortly after candle lighting), and only then accept Shabbat. In the intervening period, a woman may ask her husband to do melakhot such as turning on a light or adjusting the oven, even though she has already accepted Shabbat (SA 263:17; MB ad loc. 64). Similarly, on Saturday night one who has not yet made havdala may ask one who has to do melakha for him.
. To complete this discussion, we must add three laws. 1) The general rule that one may transgress rabbinic prohibitions during tosefet Shabbat for a mitzva or a great need does not apply to rabbinic prohibitions whose transgression is likely to lead one to a violation of Torah law. For example, one would not be allowed to do a melakha she-eina tzerikha le-gufah or to carry objects in the public domain by moving them less than four tefaĥim at a time. This is explained in MB 342:1. 2) Although the general rule is that one who has accepted Shabbat may not transgress a rabbinic prohibition unless there is a mitzva involved or a great need, the rule does not apply to asking a non-Jew to do melakha for him. This is permitted even if it is not for a mitzva or great need, as explained in MB 261:18. 3) Technically, if one has not accepted Shabbat, the rabbinic Shabbat prohibitions do not take effect until the end of bein ha-shmashot. The body of the text does not mention this because it is almost irrelevant in practice. If one is part of a local Jewish community, he may assume that the majority of the community will accept Shabbat before shki’a, and all melakhot would then be prohibited for this person as well (except for asking a non-Jew to do melakha, which is permitted during bein ha-shmashot, as explained above). If he lives in a locale where there are no Jews, there is still a mitzva of tosefet Shabbat before shki’a, and transgressing rabbinic laws will still be prohibited except for a mitzva, for Shabbat, or for a great need, when he may be lenient, as we have learned.
A woman who has good reason to travel by car after lighting candles, such as to go to the Kotel, to shul, or to see her family, may get into a car if the driver has not accepted Shabbat yet. However, she must make sure not to open or shut the car door herself if this would make the light inside the car go on or off (see Harĥavot).