What Are Low Voltage Systems?

Low voltage systems are electrical systems that operate at 50 volts or below. In buildings, this includes data networking, telephone, security cameras (CCTV), access control, intercoms, audio/visual, and fire/life safety systems. These systems carry data, audio, video, and control signals rather than power for loads.

Structured Cabling

Structured cabling is the foundation of a building's telecommunications infrastructure. A proper structured cabling system includes:

  • Horizontal cabling — from the Telecommunications Room (TR) to individual workstations (typically Cat6 or Cat6A)
  • Backbone cabling — between TRs and the Main Distribution Frame (MDF), often fiber optic
  • Patch panels and switches — where cables terminate and connect to the active network equipment

Standards like ANSI/TIA-568 govern cable types, connector pinouts (T568A or T568B), and channel performance requirements.

Access Control Systems

Access control restricts entry to authorized personnel. Modern systems consist of:

  • Card readers (proximity cards, smart cards, mobile credentials)
  • Electric locks (electromagnetic locks, electric strikes, or electrified hardware)
  • Access control panels (hardware that makes the grant/deny decision)
  • Access control software (manages credentials, schedules, and reports)

Most enterprise systems use IP-based controllers that communicate over the building's data network.

CCTV and Video Surveillance

Modern video surveillance uses IP cameras that transmit compressed video over standard Ethernet networks to a Network Video Recorder (NVR) or Video Management System (VMS). Design considerations include:

  • Camera resolution and field of view requirements
  • Storage capacity (based on number of cameras, resolution, frame rate, and retention period)
  • Network bandwidth (a 4K camera can use 16–32 Mbps)
  • Power over Ethernet (PoE) — most IP cameras are powered via the network cable

Integration With BMS

In smart buildings, low voltage systems increasingly integrate with the BMS. When an access card is denied multiple times, the security system alerts the BMS. When motion is detected after hours, the BMS turns on lights in that zone. This integration creates more responsive, efficient, and secure buildings.