MB4 232b: Eruv Chatzeros Bracha (366:10-14)

From what age can a minor accept the eruv chatzerot on behalf of the other residents? A spouse or child accepting the eruv on behalf of the other residents.

When you make an eruv on behalf of others, you can tell them on Shabbos.

A retroactive eruv chatzerot (e.g. all the residents of the chatzer are eating together when Shabbos begins).

A legal guardian (אפוטרופוס) participating in an eruv chatzerot on behalf of a minor.

Making an eruv chatzerot is a mitzvah (in order to prevent people from accidentally violating הוצאה on Shabbos).

Making an eruv tavshilin and an eruv chatzerot together with one bracha.