Electrical installations

An electrical installation is a functional entity composed of electrical appliances, installation materials, cables, switchboards, etc.

Electrical installations should be safe and meet the requirements set for them. The possessor of an electrical installation is responsible for its safety and conformity.

Installation categories of electrical installations

Electrical installations are divided into the following categories based on their certification and periodic inspection requirements and requirements related to their maintenance programme.

Installation category Installation
Category 3 Networks of electricity distribution network companies
Category 2 Electrical installations with parts of over 1,000 V inside or outside buildings (high-voltage subscribers) and low-voltage subscribers with capacity of over 1,600 kVA
Category 1

Residential buildings of more than two apartments

Electrical installations in non-residential buildings with main fuses or similar of over 35 A (e.g. public buildings, business premises, industrial and agricultural buildings, outdoor areas)


Safety during the life cycle of electrical installations

Use a professional designer.

Installation, commissioning and changes
Make sure that electrical installations are safe and compliant with the relevant requirements, have commissioning and other inspections carried out.

Possessor and operation supervisor of an electrical installation
The possessor of a category 2 or 3 electrical installation must appoint an operation supervisor for the installation.

Maintenance and periodic inspections
Monitor the condition of electrical installations and fix any deficiencies.

Taking out of service
Make sure that the electrical installation that has been taken out of service does not pose a threat.