The standard IEC 61439 practice workbook

LV switchgear and controlgear assembly

This workbook contains general information and proposals for designing, planning and building low voltage switchgear and controlgear ASSEMBLIES in compliance with the applicable laws, directives and provisions.

Basic knowledge in electrical engineering is essential for planning low voltage switchgear and controlgear ASSEMBLIES.

This workbook includes general and special information which is essential for safe, reliable and economical low voltage switchgear and controlgear ASSEMBLY operation. In addition, the topics designed to protect people and assets are being dealt with.

How are ASSEMBLIES dimensioned?

ASSEMBLIES are dimensioned through the definition of interface values.

1) Connection to the electrical system

• Nominal voltage of the incoming supply
• Electrical system
• Rated current
• Short-circuit withstand strength
• Overvoltage
• Connecting cable

2) Electrical circuits and loads

• Distribution circuits for load-side sub-distribution panels
• Final circuits

3) Installation and environmental conditions

• Indoor installations
• Outdoor installations
• Dimensions for transport and installation

4) Operating and servicing

Operation through:

• Device activation
• Access control

Safety

The new standard does not only precisely define the responsibilities of the market participants, but also specifies the dimensions of low-voltage
switchgear and controlgear ASSEMBLIES.

Which are the dimensioning specifications enabling design verification? One important aspect emphasised in the IEC 61439 is the earthing system as this has important consequences for planing the electrical circuits.

Suggested Reading – Fundamental concepts of schematic drawings: Going deeper into analysis and design intricacies

Fundamental concepts of schematic drawings: Going deeper into analysis and design intricacies