ELVs

ELVs, or extra-low voltage systems, refer to electrical networks and components designed to operate at voltage levels low enough to pose minimal risk of electric shock under normal conditions. In many international standards, extra-low voltages are defined as not exceeding 50 V alternating current or 120 V direct current, though exact limits vary by country or standard. ELV arrangements are typically isolated from or separately protected from higher voltage distribution to enhance safety and reduce electrical fire risk.

ELV applications are diverse and common in modern buildings. They include telecommunications, data networks, security and access control, fire alarm and life-safety systems, building automation, audiovisual and lighting control, and other specialized control circuits. Technologies frequently used in ELV systems include low-voltage power supplies, Power over Ethernet (PoE), structured cabling (such as CATx and fiber), CCTV and security sensors, intercoms, door controllers, and various smart-building devices. Because ELV functions often operate continuously or monitor critical building operations, reliability and maintainability are priorities in their design and deployment.

Standards and safety considerations vary by jurisdiction, but ELV circuits are typically subject to local electrical codes. In some regions they are treated as Class 2 or Class 3 circuits with restricted power to limit shock hazards. Installations emphasize proper cabling practices, containment, appropriate insulation, grounding or bonding as required, fire-stopping where needed, surge protection, and separation from higher-voltage distribution. While ELV systems carry a lower risk of electric shock, they still require careful engineering to ensure safety, interference control, and dependable operation within the overall building electrical system.