Separation of busbars from the functional units and separation of all functional units from one another.

Separation of the terminals for external conductors from the functional units but not from one another.

– Protection against contact with live parts.

– Limitation of the risk of faults between each of the functional units ( propagation of electrical arcs, etc.)

TWO TYPES OF A FORM 3 SEPARATION AS SPECIFIED BY I.S. EN 60439-1

FORM 3A:

Terminals for external conductors not separated from the busbars. The functional units are separated from one another and from the busbars, but the terminals for external conductors are not.

FORM 3B:

Terminals for external conductors separated from the busbars. The functional units are separated from one another and from the busbars. The terminals for external conductors are separated from the functional units but not from one another.