Main Distribution Board (Mdb) 

A Main Distribution Board (MDB) is the main electrical board in a building. It distribution power to the secondary distribution boards (SDBs) or final sub-circuits. The definition of an MDB varies by country, but typically an MDB will have a voltage no higher than 1,000 volts AC or 1,500 volts DC. An MDB will also usually have circuit breakers and fuses to protect the wiring from overloads.