One each of the eight evenings of Hanukah, we light Hanukah candles in the synagogue for the purpose of "Pirsumeh Nisa" – publicizing the miracle. After Minha, before Arbit, somebody lights the candles in the synagogue and recites all the Berachot ("Le’hadlik," "She’asa Nissim," and, on the first night, "She’hehiyanu").
Hacham Ovadia Yosef ruled that the candles should be lit after Minha wherever a Minyan has assembled, and not only in the synagogue. Thus, if a Minyan for Minha is held in a person’s office, Hanukah candles should be lit – with the recitation of the Berachot – after Minha. Since the candles are lit for the purpose of publicizing the Hanukah miracle, this custom does not apply only to a synagogue; it applies anywhere a group has gathered.
By the same token, then, it would be appropriate to light Hanukah candles at any large gathering held during the evening on Hanukah, such as a wedding or other celebration or community function. Hacham Ovadia Yosef ruled that the Berachot may be recited over the candle lighting, though he adds that it is preferable to recite Arbit after candle lighting, so that the gathering will resemble the synagogue setting. Since a large gathering has assembled, and the goal of publicizing the miracle is achieved through the candle lighting, the Berachot may be recited, especially considering the likelihood that many people in attendance had not yet lit the Hanukah candles.
Summary: Just as Hanukah candles are lit with the Berachot in the synagogue between Minha and Arbit during Hanukah, similarly, candles should be lit with the Berachot wherever people gather for Minha during Hanukah, even an office. Likewise, candles should be lit at any large gathering in the evening during Hanukah, such as weddings or other functions, and the Berachot may be recited. Preferably, Arbit should be recited immediately after the candle lighting.
