Published by the International Electrotechnical Commission (IEC), IEC 61439-1 defines the general requirements for low-voltage switchgear and controlgear assemblies. It applies to everything from power distribution boards in buildings to motor control centers in industrial facilities. An electrical assembly is a combination of more protection and switching devices, grouped together in one or more adjacent cases (column). A collection of one or more of these. Did you know that a poorly designed electrical installation can shut down an entire production line? While it may seem simple, low voltage electrical installations are the backbone of any automated industrial system. Standard-IEC-61439-workbook-in. Key parts include: These standards define requirements.