ELV (Extra-Low Voltage)
ELV — extra-low voltage — is the discipline of a building's signalling, communication and security systems: CCTV, access control, public address and voice evacuation, fire detection interfaces, structured cabling and networking, EPABX and intercom, and building management. Electrically small, it shares containment and ceiling space with every other service and is coordinated as part of the MEPF design or arrives last.
Why it matters on an MEPF project
ELV is not in the MEPF acronym and is decided by it: its cables share trays and risers with power, its voice-evacuation system is part of the fire scheme in the occupancies NBC 2016 Part 4 requires it in, and its access-control doors have to release on fire alarm. Let separately and last, it fights for space that is already taken and integrations that nobody defined.
The other thing ELV carries is data: recordings, access logs, network traffic. Retention, separation from power, and who can export what are design decisions, not afterthoughts — and a structured-cabling backbone that is not certified is not the category cable its label claims.
How it's specified in practice
| Parameter | Typical / working position | Governing reference |
|---|---|---|
| CCTV | Cameras by what must be identified at what distance; storage by retention | IEC 62676; ONVIF |
| Access control | Fail-safe / fail-secure per door; release on fire alarm | Fire cause-and-effect |
| PA / voice evacuation | Zoned to the evacuation strategy; intelligibility, not loudness | NBC 2016 Part 4 |
| Structured cabling | Cat6/6A + fibre backbone, certified link by link | TIA-568 |
Common mistakes
- ELV tendered last and given the leftover ceiling space.
- Data cables run alongside power without separation.
- Voice evacuation omitted where NBC requires it.
- Access-control doors with no fail-state decision tied to fire egress.
Related on this site
One of 68 working definitions in the MEPF & solar engineering glossary. The buying side of the same decisions is in the buyer's guides; the numbers are in the calculators.
Frequently asked
Is ELV part of MEPF?
Not by the acronym; in practice, yes. It shares containment and ceiling void with every MEPF service and its voice-evacuation and access-control systems are part of the fire cause-and-effect — so it is coordinated in the MEPF design or it arrives last and fights for space.
Standards referenced: NBC 2016 Part 4 (PA / voice evacuation) · TIA/EIA-568 · IEC 62676