Many congregations have the practice during the summer months of accepting Shabbat early, before sundown on Friday afternoon. The men go the synagogue, recite Minha, Kabbalat Shabbat and Arbit, and return home well before sundown. The question arises in this situation as to whether or not the wife is bound by the husband’s acceptance of Shabbat. If, for example, the husband estimates that he will recite Kabbalat Shabbat and thus accept the onset of Shabbat at 7:15pm, must he instruct his wife to complete all Shabbat preparations and light the Shabbat candles by 7:15? A famous Halachic principle known as "Ishto Ke’gufo" establishes that a husband and wife are considered a single unit. Seemingly, then, once a husband accepts Shabbat, the wife must likewise accept Shabbat at that point, and may therefore not perform any Melacha (activity forbidden on Shabbat) past the time when her husband accepts Shabbat.
In truth, however, this is not the case. Hacham Ovadia Yosef explicitly rules that a husband and wife accept Shabbat separately, and are not bound by the other’s acceptance. Strictly speaking, then, it is possible for the husband to return home from the synagogue on Friday night during the summer months and find his wife still turning on and off lights, dealing with the oven, lighting candles, and so on. Since the wife is not bound by the husband’s acceptance of Shabbat, she may continue performing Melacha until the time for Shabbat candle lighting eighteen minutes before sunset. Needless to say, once the wife lights the Shabbat candles, she accepts the onset of Shabbat and may no longer perform Melacha.
The also applies in the reverse case. Meaning, if a wife accepts Shabbat early, before the other members of her family, her acceptance is not binding upon them, and they may still perform Melacha.
It should be noted that the restrictions of "Amira Le’akum" – asking a gentile to perform Melacha on Shabbat on one’s behalf – do not apply to asking Jews. For example, if somebody accepted Shabbat early, before sunset, and then realizes that he mistakenly left his bedroom light on, he may ask another Jew who has not yet accepted Shabbat to turn off the light. There is no prohibition against asking a fellow Jew to perform Melacha on one’s behalf if he has yet to accept Shabbat and the sun has not yet set. This applies after Shabbat, as well. For example, many people extend their Se’uda Shelishit meal until well after nightfall, by which time many other people have already recited Habdala and ended Shabbat. It would be permissible in such a situation to ask somebody who has ended Shabbat to perform Melacha on his behalf, such as to bring him something from his car. Even though the one making the request has not yet ended Shabbat, he may ask a fellow Jew to perform Melacha for him if that other Jew has already ended Shabbat.
Summary: Even though a man accepted Shabbat early, before sundown, his wife is not required to accept Shabbat at that point, and she may continue performing Melacha until the usual candle lighting time. A person who accepted Shabbat early may ask a fellow Jew who has not yet accepted Shabbat to perform Melacha for him. Similarly, a person who did not yet end Shabbat on Saturday night may ask a person who did end Shabbat to perform a Melacha for him.
