The custom is to light the Menorah in the Bet Knesset with Berachot. On Friday, it is lit, before Minha, once a Minyan is present. On Mosa'eh Shabbat it is lit during Arbit before the Kaddish Titkabal, before people rush home.
This custom was not recorded in the Gemara, but it was accepted by the Shulhan Aruch. The question is whether a Menorah should be lit also at public gatherings, such as parties, restaurants and conferences, outside of a Bet Knesset. Hacham Bension was very strict on this matter. He reasoned that even lighting in a Bet Knesset with a Beracha is a Hidush, and therefore it should not be expanded upon to other contexts.
On the other hand, Hacham Ovadia was more lenient. He ruled that the Bet Knesset is only an example of a public gathering, but the custom could be applied to other venues as well. This is especially applicable if some people at the event will not be lighting on their own at home. It can be assumed that at a wedding with hundreds of people, some people will not be lighting at home. In addition, he rules (Yalkut Yosef English Edition) that a Menorah may be lit at a Minyan not taking place in a Bet Knesset, such as a Minha/Arbit Minyan in an office.
In this disagreement between Hacham Bension and Hacham Ovadia, one may rely on Hacham Ovadia.
SUMMARY
One may light a Menorah with Berachot at public gatherings, if there are people there who may not light on their own. Similarly, a Menorah may be lit at a Minyan in an office.
