Eristysluokkia

Eristysluokkia, known in English as insulation classes, are classifications used to define the level of electrical insulation protection provided by electrical equipment. These classes are standardized internationally, primarily through IEC (International Electrotechnical Commission) standards, to ensure safety and compatibility across different regions and manufacturers.

The primary purpose of insulation classes is to protect users from electric shock by preventing current from flowing through the human body. Equipment is categorized into different classes based on its construction and how the protective earth connection is integrated. For example, Class I equipment relies on basic insulation and an protective earth connection to ensure safety. If the basic insulation fails, the exposed conductive parts are connected to earth, preventing a dangerous voltage from appearing.

Class II equipment, often referred to as double-insulated or reinforced-insulated, offers a higher level of protection. These devices have either double insulation or reinforced insulation, meaning that both basic insulation and supplementary insulation are present, or a single insulation system of equivalent strength is used. This eliminates the need for a protective earth connection, as the insulation itself provides sufficient protection against electric shock.

Class III equipment is designed to be supplied from a Safety Extra Low Voltage (SELV) source. The voltage in SELV systems is low enough that under normal conditions, and in single-fault conditions, it does not give rise to danger from electric shock. Therefore, Class III equipment does not require protective measures against electric shock beyond the SELV supply itself. Understanding these insulation classes is crucial for selecting and using electrical equipment safely in various applications, from household appliances to industrial machinery.