The primary distribution box refers to the main distribution box, typically located in the distribution room. Use the Exchange admin center (EAC) or the Exchange Management Shell to create a new distribution group in your Exchange organization or to mail-enable an existing group in Active Directory. Let's make an example for clarity: A newly constructed residential area introduces a 10kV power line to a substation. From the transformer's low-voltage side (0. It is a vital part and central hub of any electrical system. Whether it's a home, office, or factory, the DB box makes sure power.