A distribution board is where the electrical supply is distributed from within the building. The main supply cable comes into the board and is then distributed to the breakers and from there to all the circuits (e.g. lights, plugs etc.). The power distribution board usually houses all the contact breakers, earth leakage unit and may house items such as a door bell transformer and timers. There are various sizes of power distribution boards available.
The main power distribution board is usually in the house where the main electrical cable enters and smaller boards, together with contact breakers and possibly earth leakage units are at other points, such as swimming pool pumps, gate motors and outbuildings.
Various types of power distribution boards are available, such as surface mounted, flush mounted or floor standing, with closing doors or see through plastic covers or doors and in different sizes which are determined by the number of circuits rewired within the board.
The interior of the power distribution board is pre-fitted with a clip tray or DIN rail for mounting the miniature circuit breakers (MCB) and other devices. There are two different types of MCB's referred to as “mini rail” or “DIN” which are only interchangeable if special adaptor brackets are used.
Power distribution boards can be purchased either as an empty enclosure to enable the contractor to equip it, or as a ready wired standard unit, or as a specifically manufactured item to the client's requirements. Also available are distribution boards or specific applications such as swimming pools, ready boards for low-cost housing, irrigation systems etc.
Each power distribution board must be controlled by a switch disconnector (mains or main switch).