Step 1: Collecting all the project data The user specifi es the operational requirements and conditions for a low-voltage switchgear assembly. The correct rating of the key interfaces in the switchgear assembly is crucial for its function under operating conditions. For this purpose, the switchgear assembly is considered a » BLACK-BOX« with four interfaces for which the manufacturer of the switchgear assembly must defi ne the correct design values when designing the assembly.
Where special operating conditions exist that are not covered by the standard, in addition also the applicable special requirements have to be met or special agreements between the manufacturer of the switchgear assembly and the user must be made. The user must inform the manufacturer if such extraordinary conditions exist. The design of the switchgear assembly is dependent on the conditions and data such as:
1.1 Installation and ambient conditions 1.2 Operation and maintenance 1.3 Connection to the public power supply system 1.4 Electrical circuits and consumers Interface characteristics of assemblies Switchgear assembly as BLACK BOX with the 4 interfaces according to IEC 61439 / EN 61439 1.1 Conditions at place of installation/environment 1.2 Operation and maintenance - (Device) operation by ordinary persons - unskilled persons - Installation site - Special requirements for use in commercial and industrial applications - Access and operation only by skilled persons (electricians) BLACK BOX ENYSTAR Combinable enclosure system, insulation- enclosed, totally insulated, IP 66, for the assembly of distribution boards up to 250 A intended to be operated by ordinary persons (DBO) according to IEC/EN 61439-3 Mi Distributor Combinable enclosure system, insulation- enclosed, totally insulated, IP 65, for the assembly of power switchgear and controlgear assemblies (PSC) to 630 A in accordance with IEC/EN 61439-2 1.3 Connection to the public power supply system 1.4 Electrical circuits and consumers - Rating of outgoing circuits - Nominal data of the feed - Nominal values transformer - Short-time withstand current - Determination of the thermal power dissipation - Determination of the rated diversity factor (RDF) 8