8 - Constructional Requirements

Last edit: 28/06/2023

Chapter 8 of the Standard provides the construction requirements to follow. In particular, EN IEC 61439-1 specifies that assemblies shall be constructed of material capable of withstanding the mechanical, electrical, thermal and environmental stresses that are likely to be encountered in specified service conditions. The compliance with these requirements allows to avoid also the formation of electric arc inside the enclosure.

The degree of protection provided by any assembly against contact with live parts, ingress of solid foreign bodies and water is indicated by the IP code. The degree of protection of an enclosed assembly shall be at least IP2X. The degree of protection provided from the front of a dead front assembly shall be at least IPXXB. For assemblies for outdoor use having no supplementary protection, the second characteristic numeral shall be at least 3. 
The IP code shall be given after appropriate verifications. 

The apparatus and circuits in the assembly shall be so arranged as to facilitate their operation and maintenance, and at the same time to ensure the necessary degree of safety. 

Basic protection can be achieved either by appropriate constructional measures on the assembly itself or by additional measures to be taken during installation; this may require information to be given by the assembly manufacturer. Additional measurers, in order to isolate live parts, are insulating materials, barriers or enclosures

In the first case, live parts shall be completely cover with insulation that can be removed by destruction or by the use of a tool.
In the second case, live parts shall be inside enclosures or behind barriers providing at least a degree of protection of IPXXB.