A Distribution Board or DB is generally a consumer unit that is used in larger, more power hungry electrical installations such as industrial and commercial settings. They are often larger than the traditional consumer unit found in your house, although ultimately operate in much the same way.
Distribution boards, will often be Three Phase, used for more demanding applications and larger motors for example
A DB divides the incoming electrical power supply into subsidiary circuits. These circuits are provided with a protective fuse or circuit breaker with the rating depending on the cables size, installation method and length.
A distribution board can feed multiple other DB’s known as Distribution Circuits or sub-main’s