SELVtingimused

SELVtingimused, also known as Separately Derived Electric Power Systems (SDEPS) in English, refer to electrical systems that are designed to provide safety in environments where electrical hazards pose a significant risk. The term originates from the Estonian language, where "SELV" stands for *separate elektriline võimsus*, meaning "separate electrical power." These systems are primarily used in medical, industrial, and residential settings to minimize the risk of electric shock and ensure compliance with safety standards.

SELV systems operate at low voltages, typically below 60 volts for alternating current (AC) or 150 volts for direct current (DC), to reduce the likelihood of severe injury in case of accidental contact. The key principle behind SELV is electrical isolation, where the power source is separated from the user through transformers, voltage regulators, or other isolation methods. This separation prevents the system from being connected to a higher-voltage supply that could conduct dangerous currents.

In Estonia and other regions following similar safety regulations, SELVtingimused are regulated by standards such as the European Norm EN 60950-1 for information technology equipment or national electrical codes. Compliance ensures that devices and installations meet safety requirements, reducing risks in sensitive environments like hospitals, laboratories, or homes with vulnerable users. Proper implementation involves careful design, testing, and certification to guarantee reliability and user protection.

SELV systems are often used in conjunction with other safety measures, such as residual current devices (RCDs), to enhance overall electrical safety. While they do not eliminate all risks, they significantly lower the potential for electric shock by limiting voltage exposure and ensuring isolation from higher-risk circuits.