A Form 4b panel is a low-voltage switchboard design with the highest level of internal separation according to IEC 61439 / IEC 60439 standards. It is commonly used in critical power distribution systems such as large industries, hospitals, data centres, and power plants.
The purpose is to increase safety, reliability, and ease of maintenance.
Meaning of Form 4b
In Form 4b, the panel is internally separated so that:
Busbars are separated from functional units (breakers, contactors, etc.).
Each functional unit is separated from others.
Cable terminals are separated from busbars.
Cable terminals of each unit are separated from other units.
This means each outgoing feeder has its own compartment, improving safety.