överspänningskategori

An överspänningskategori, or overvoltage category, is a classification system used in electrical engineering to denote the level of transient overvoltage protection required for electrical equipment. These categories are defined by international standards, most notably IEC 60664-1, which deals with insulation coordination for equipment within low-voltage systems. The categories, numbered I through IV, represent different environments where electrical installations are found, with higher numbers indicating a greater likelihood of experiencing severe transient overvoltages.

Category I applies to equipment that is connected to a mains power supply but is protected by surge suppression devices located upstream. This typically includes electronic devices with secondary surge protection. Category II is for equipment that draws power from the fixed electrical installation, such as general-purpose appliances and portable tools. Category III covers equipment in fixed installations, like distribution boards, switchgear, and industrial equipment. Finally, Category IV is designated for equipment connected at the origin of the electrical installation, such as electricity meters and main incoming power lines, which are most susceptible to external transient overvoltages originating from the public supply.

The purpose of these categories is to ensure that electrical devices are designed with appropriate insulation and surge protection to withstand the expected voltage spikes. Selecting equipment rated for the correct överspänningskategori is crucial for preventing damage, ensuring safety, and maintaining the reliability of electrical systems. Failure to do so can lead to device malfunction, failure, or even fire hazards.