Form 3b? Form 4aih? Ever wondered what your consultant is referring to when they talk about forms of segregation and don’t want to look stupid?
As defined by AS61439 they are methods by which the busbars and functional units of an Assembly can be internally separated. The standard outlines 4 main Forms of Segregation:
- Form 1 – No internal separation of the busbars, functional units and terminals from each other.
- Form 2a – Separation of the busbars from the functional units. Terminals are not separated from the busbars.
- Form 2b – As for 2a, but the terminals are not separated from the functional units.
- Form 3a – Separation of busbars from functional units and functional units of each other. Terminals of functional units are not separated from each other.
- Form 3b – As per 3a, but with the terminals separated from the busbar (and functional units).
- Form 4a– Functional units and terminals are separated from busbars and any other functional units and terminals.
- From 4b – As per 4a, but with the terminals for each functional unit separated in their own space.
And you guessed it – the higher the number the higher the complexity.
A few definitions:
Assembly: a switchboard containing low-voltage switchgear/control gear.
Functional unit: a collection of electrical and mechanical components within an Assembly that contribute to the fulfilment of the same function. E.g. an individual motor starter within an MCC.
Busbar: Low impedance conductor to which several electric circuits can be separately connected.
