Low Voltage & ELV Systems — CCTV, Access Control, PA

Low voltage or ELV systems are the building services that run on signal cabling rather than mains power: CCTV, access control, public address and voice evacuation, intercom and building management interfaces. They work best designed with the fit-out, with dedicated containment and access-controlled escape doors wired to release on a fire alarm.

By Dhruv Agarwal · · 1 min read

What we deliver

CCTV, access control, public address and voice evacuation, intercom, and building management interfaces — designed with the building services and installed with the fit-out rather than bolted on afterwards.

Low voltage systems are small in cost relative to the building and large in how they affect daily use and safety. They are also the systems most often left to the end, which is why they so often end up in surface conduit across a finished ceiling.

Scope of works

SystemWhat we deliver
CCTVCamera layout, coverage review, recording, cabling
Access controlReaders, locks, door release, controller, fire interface
Public addressSpeakers, zoning, voice evacuation interface
IntercomReception and entry intercom
BMS interfacesIntegration points for HVAC, lighting and alarms
ContainmentDedicated ELV trays and conduits, rack space
TestingCoverage check, interface tests, commissioning

Where projects go wrong

  • Access-controlled escape doors not released on alarm. A genuine safety failure, not a technical detail.
  • Camera positions chosen without a coverage review. Blind spots at exactly the entrances and corridors that matter.
  • ELV added after the ceiling closes. Cut ceilings and surface containment.
  • No dedicated containment. ELV sharing trays with power invites interference and confusion at every future change.
  • Rack space not planned. Equipment ends up in a cupboard with no ventilation.

Why Hagerstone

Low voltage is part of our stated MEP scope, delivered with the electrical, fire alarm and fit-out work it has to interface with — so the escape door release and the PA voice evacuation are tested against the fire alarm, not left between contractors.

15 electricians and 15 technicians in-house, under ISO 9001 / 14001 / 45001 and 79+ quality checkpoints.

Standards referenced

Fire alarm and PA interfaces under NBC 2016, Part 4. Wiring installation practice to IS 732.

Standards referenced

  • NBC 2016, Part 4 — Fire and life safety — alarm and PA interfaces (Bureau of Indian Standards)
  • IS 732 — Electrical wiring installations (Bureau of Indian Standards)

Frequently asked

The systems that run on low-voltage signal cabling rather than mains power distribution: CCTV, access control, public address and voice evacuation, intercom, building management system interfaces, and often structured cabling. They are frequently procured separately, which is exactly why they end up uncoordinated with the ceiling, the containment and the fire alarm.

Yes, where doors on escape routes are access-controlled. On a fire alarm, those doors must release so people can get out. That interface has to be designed, wired and tested — an access-controlled door that stays locked during an evacuation is a serious safety failure.

Because every camera, reader and speaker needs a position in the ceiling or wall and a cable path back to a rack. Added after the ceiling closes, that means cutting finished surfaces and running surface containment. Designed with the fit-out, it disappears into the building.

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