# 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.

## 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

| System | What we deliver |
| --- | --- |
| CCTV | Camera layout, coverage review, recording, cabling |
| Access control | Readers, locks, door release, controller, fire interface |
| Public address | Speakers, zoning, voice evacuation interface |
| Intercom | Reception and entry intercom |
| BMS interfaces | Integration points for HVAC, lighting and alarms |
| Containment | Dedicated ELV trays and conduits, rack space |
| Testing | Coverage 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**.

## Frequently asked questions

### What counts as ELV or low voltage?

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.

### Does access control need to connect to 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.

### Why coordinate ELV with the fit-out rather than add it later?

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.

## Sources

- [NBC 2016, Part 4](https://www.bis.gov.in/standards/national-building-code/?lang=en) — Fire and life safety — alarm and PA interfaces
- [IS 732](https://standards.bis.gov.in/website/published-standards/department-wise) — Electrical wiring installations

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Source: https://hagerstone.com/services/mep/low-voltage-and-elv