Tables and cabinets

Whether for electrical installations or equipment associated with machines or industrial processes, from the simplest to the most complex, all or part of certain equipment is grouped together in specific locations for specific functions such as power distribution, protection of all kinds, measurement, start-up or shut-down, automation, etc., leaving only judiciously placed local control devices available to users or operators.

These switchgear assemblies, often referred to as switchboards, cabinets, enclosures, etc., must comply with a certain number of rules (regulations, standards, specifications, etc.), each of which meets a specific objective.

They cannot be exhaustive, nor can they include what are known as the "rules of the art", an imprecise formulation that covers all knowledge acquired through experience or drawn from the application of theories and physics.

We have tried to summarize them here, referring you to the texts cited in the documentation for more details.

The designer and, in some cases, the installer or user, must answer a number of questions which are the basis of the design; in their absence, parameters can only be set a priori, which can become awkward in the long run:

• related regulation(s) ;

• intended application(s) ;

• environmental conditions ;

• operating conditions (upstream short-circuit power, switching frequency, etc.);

• maintenance arrangements (accessibility, unplugging, markings, drawings and diagrams, terminal block lists, notices, wording of instructions, etc.).

The electrotechnical sector is one of the most heavily regulated, and is subject to a large number of standards. Existing national regulations will only be phased out or harmonized slowly; however, European directives, transposed into French law, come into force as soon as they are published, and modify, supplement or add to regulations.

Standardization is essentially carried out at the international level, by IEC worldwide, with CENELEC taking over for Europe, while modifications in line with European specificities or accepted national derivations remain fairly limited.

To date, it is safe to assume that both directives and standards have come a long way, subject to updates and additions necessitated by technological, economic or social developments.

In this article, we have limited ourselves to independent assemblies intended for the distribution of electrical energy, the electrical protection of circuits and users, and the functions...