Upgrade of Distribution Boards
Standard Practice is to oversize a Distribution Board by 30%. This means if any future work is undertaken there is adequate space. Some Electrical Contractors will order and install a Distribution Board that leaves no room for expansion.
There are two different types of Distribution Boards, DIN (International Type) and Samite (Old South African Design)
Then there is a flush or surface mounted distribution Board.
Consideration must also be given if three phase needs to be installed, the balancing of the load across the three phases.
The Main Circuit Breaker needs to be taken into account. Anything above 100Amp 10Ka, would normally require a specific type of Distribution Board, then one may consider installing separate busbar units.
Larger Circuit Breakers, have different physical sizes, and the depth must be taken into account.
Number of cables, the size of cables, the size of cable glands must also be considered.
Old Distribution Boards often have an impaired earth conductor; a few years ago the armouring of the main cable was used as the main earthing conductor. Now a separate earth cable is required.
The hight of the distribution board and the location of the isolator must also conform to SANS10142-1.
Below are some SANS 10142-1 Wiring Standards that Distribution Boards must comply to:
6.1.4 All the conductors of any circuit shall originate at the same distribution board.
6.1.5 A maximum of three conductors may be connected to any one terminal provided that the terminal has the correct rating
6.1.6 The neutral conductor shall not be connected direct to earth or to the earth continuity conductor on the load side of the point of control.
126.96.36.199 Each distribution board shall be controlled by a switch-disconnector.
The switch-disconnector shall
a) be mounted in the distribution board or adjacent to the distribution board
in the same room
b) in the case of the main or first distribution board of an installation, be labeled as "main switch",
c) in the case of a sub-distribution board, be labeled as "sub-main switch" or “main switch” if the board is labeled sub-board
e) have a danger notice on or near it. The danger notice shall give instructions that the switch-disconnector be switched off in the event of inadvertent contact or leakage.
188.8.131.52 The distribution board shall be suitable for the environmental
conditions in which it operates.
184.108.40.206 Distribution boards shall be protected against corrosion.
220.127.116.11 Any point of a distribution board that has to be reached during normal operation shall not exceed a height of 2,2 m above floor (or walking) level.
However, the board may be mounted higher if it can be disconnected from the supply by a switch-disconnector that is less than 2,2 m above floor level. (See also 5.2.8(b)). Unless a residential distribution board is housed in an enclosure and direct access cannot be obtained by an infant.
An indoor distribution board shall be less than 1,2 m above the floor level and no part of an outdoor distribution board shall be less than 0,2 m above the ground level.
18.104.22.168 A distribution board shall not be mounted
a) in a bathroom, except outside zone 3 and unless the enclosure provides an IP rating of IPX5 (see 22.214.171.124.6),
b) above a fixed cooking appliance or in a position where a cooking appliance could be put below it, unless the enclosure provides a degree of protection of at least IP44, or Amdt 6
c) within a radius of 1 m from a water tap or valve (in the same room), unless the enclosure provides a degree of protection of at least IP44.
126.96.36.199 Wiring and feeder cables or tightening of connections shall not
cause displacement of components.
188.8.131.52 Distribution boards shall be so positioned and arranged as to ensure safe operation and maintenance (see 5.2.8). Amdt 3
184.108.40.206 Text has been renumbered and moved to 220.127.116.11. Amdt 5
18.104.22.168 If a conductor of cross-sectional area exceeding 4 mm2 is used, it shall be so installed to allow any one neutral conductor to be disconnected without disturbing the connection of any other neutral conductor.
22.214.171.124 A distribution board and the equipment mounted in or on it shall be so positioned and arranged that any conductor can easily be disconnected from the terminals.
Contact RSA Bardo Electrical Systems for your Distribution Board Upgrades or New Installations.