Low-voltage pre-wire for a multi-family building before drywall
On most multi-family projects, low-voltage is the last scope drawn and the first one blamed. By the time a low-voltage pre-wire for a multi-family building gets priced, the risers are framed, electrical is roughed, and the only pathway left is the one nobody else wanted. Almost every expensive low-voltage problem is a decision that was made — or skipped — before drywall.
Low-voltage belongs in the drawing set, not in a change order
Low-voltage should be drawn during design development, alongside electrical and mechanical, and carried into the permit and tender set. That is the last point at which the building can still be shaped around it.
A usable set defines device locations and counts, telecom room size and placement, a riser diagram, pathway and sleeve sizing, power, cooling and bonding in the main room, and backing requirements. Without those, the trade arrives with cable and no route.
The most common gap is not a missing cable but a missing room: a telecom closet drawn like a broom closet, with no power, no cooling and no floor space in front of the rack. Rooms are structural. Cable is not.
Fire alarm is a separate regulated system with its own contractor, permit and inspection; do not fold it into the low-voltage package because it happens to be low-voltage. Permit and inspection questions are jurisdiction-specific — confirm them with the authority having jurisdiction.
What a low-voltage pre-wire for a multi-family building includes
It is two packages with two owners: what is inside the suite, and what belongs to the building. Confusing them at tender is how scope falls between the electrical contractor, the security contractor and the door hardware supplier.
| Scope | Usually includes | Owned after turnover by |
|---|---|---|
| Suite | Cat6/6A home runs from a powered suite panel to living areas and bedrooms, data and TV outlets, intercom station path, automation and shade wiring where in scope | The suite owner or tenant |
| Common areas | Cameras, readers and door hardware paths, entry and gate intercom, corridor Wi-Fi, elevator paths, parkade and site conduits, the building network | The strata or building owner |
| Service entrance and risers | Carrier entrance conduit, demarcation room, backbone fiber and copper between floors, sleeves, spare capacity | The building owner; carriers occupy space in it |
The split matters beyond cost allocation. Suite finishes can change late and cheaply; risers cannot. Common-area systems also carry obligations the suite side does not: cameras and access logs record residents and staff, and retention, sightlines and viewing rights carry privacy obligations in BC that should be reviewed with the strata or owner and legal counsel before commissioning. Both access control and surveillance run on this same cabling.
Risers, pathways and telecom rooms
Risers and pathways are the only part of the pre-wire that cannot be redone cheaply. Everything else is cable through an existing route.
Stack the telecom rooms vertically so the riser runs straight floor to floor, and size each one for the equipment that will live there in year ten: rack, patch panels, switches, access controller, intercom head end, local recording, plus whatever the carriers install. Give it power, cooling, a plywood backboard and a lockable door, and keep it out from under wet rooms.
The 90 m constraint is measured along the cable, not the plan
A balanced twisted-pair horizontal channel is limited to 100 m — roughly 90 m of fixed cable plus patch cords at each end. That is routed length: up the wall, across the ceiling, around the shaft, plus slack. On a long-wing floor plate the far suite is often well past what the plan suggests, and the answer is another telecom room on a fiber backbone, not a longer copper run. Cat6A carries 10GBASE-T across the full channel, worth specifying on backbone and commercial-tenant drops even where Cat6 is fine in a suite.
Sleeves and spare capacity
Size sleeves for the final bundle and add spares; the first two systems installed will consume whatever was provided. Put a pull string in every empty conduit. Penetrations through rated assemblies have to be firestopped and the assembly restored by a method suited to it — confirm the requirement locally.
Under-slab work is the one-shot item: gate operators, loop detectors, bollard intercom, site camera stubs, EV load-management pathways and the carrier conduit to the property line. Once the slab is poured that route is gone, and carrier coordination runs on the utility's schedule, not yours.
What gets stubbed, and where
Anything that will sit behind a finished surface, inside a rated assembly, or under concrete has to be stubbed while it is open.
| Location | Rough in before close-in | Why it cannot wait |
|---|---|---|
| Building entry | Cat6 to the intercom or door station, reader and lock hardware path, camera above the door, backing behind the panel | Stone, tile or glass; coring one later is visible forever |
| Corridors and amenity rooms | Access point and camera drops, stairwell and amenity door hardware, backing for displays | Closes early; the most contested space in the building |
| Elevator | Cab camera path through the traveller, lobby camera and reader, machine room drop | Specified with the elevator, months before the cab arrives |
| Parkade and site | Gate operator and loop conduits, bollard intercom, ramp camera stubs, EV load-management path | Buried in slab, in poured walls, or under grade |
| Suites and suite entry | Home runs to the suite panel, data and TV outlets, intercom station, keypad and shade runs; reader and door contact paths where suite doors are on the system | Frames are set early and no path exists once the board is up |
| Roof and exterior | Camera and antenna stubs with conduit down to the nearest room | Membrane penetrations after roofing become a warranty argument |
What a missed stub costs later
The cable was never the expensive part. What multiplies after drywall is access: coring and restoring a rated assembly, surface raceway where concealed cable was intended, paint that never matches, and scheduled entry to occupied suites. A drop that was minutes of work at rough-in can absorb most of a day once people live there, and it changes who pays — a construction line item becomes a strata special levy.
Pulling one spare Cat6A to a likely location while the wall is open costs the cable and a few minutes — the cheapest insurance in the structured cabling package.
Sequencing low-voltage against the construction schedule
Low-voltage rough-in occupies a narrow window between mechanical and electrical rough-in and insulation, and that window moves. Book it against the framing schedule floor by floor, not against one project milestone.
| Milestone | Low-voltage activity | Locked after this point |
|---|---|---|
| Design development | Device counts, telecom room size and location, riser diagram into the set | Room sizes, riser location |
| Permit and tender | Scope split across communications, security, electrical and door hardware; cable, testing and labelling specs | Who is responsible for what |
| Trade buyout | Coordination drawings with electrical and mechanical; door hardware interface review | Ceiling and wall space |
| Site servicing and slab | Under-slab conduit, gate and EV pathways, carrier entrance | Anything under concrete |
| Framing | Sleeves, backing, box and bracket placement, riser conduit | Wall depth and backing |
| Before insulation | Home runs pulled, labelled both ends, coiled and protected; photograph every wall | Everything concealed |
| Termination | Racks, patch panels, terminations, certification testing | Rack layout |
| Trim and commissioning | Devices, programming, credentials, test results, as-builts, training | — |
Dated photos of every open wall, indexed by suite number, are the cheapest as-built record available and settle most disputes about what is behind the board. Telecom rooms also get used as material storage during finishing; write them out of the rotation before the racks go in.
Trade separation is decided here too. Low-voltage and power should be separated where they run parallel and crossed at right angles where they must meet, and stud depth has to suit both trades' boxes and conduit. Automation adds framing dependencies of its own — neutrals at switch locations, low-voltage power at window heads for shades, keypad backing — so smart automation has to be decided before rough-in, not at trim.
The handover package to demand
Specify the handover documents in the tender, not at substantial completion. Anything not specified arrives as a box of patch cords and a phone number.
- As-built drawings of final device locations and cable routes, not the design drawing reissued
- A port and outlet schedule matching the labels on the cable, the plate and the patch panel
- Certification results for every drop, in a readable format, including failures and the repairs made
- Rack elevations, patch panel schedules, and a riser diagram with fiber counts and spare capacity
- Device inventory: model, serial, MAC address, firmware version and location
- Administrative credentials transferred to the owner or strata, with the integrator's own access documented and revocable
- Warranty start dates, with the labour warranty stated separately from manufacturer warranty
- A record of what was left spare: empty conduits, pull strings, unused sleeves, free ports
Credentials are the item most often skipped and the most damaging to skip. A building whose cameras, access control and network are reachable only through the installer's account cannot change vendors without reconfiguring them from scratch. Make the transfer a condition of final payment.
What to do next
Get low-voltage into the drawing set at design development, fix the telecom rooms and riser first, and write the handover package into the specification while it can still affect price. Long floor plates and complex parkades should be resolved before tender closes.
Orbit Automation is a licensed and insured low-voltage integrator in Surrey serving Metro Vancouver and the Fraser Valley; we can review a drawing set or walk a site before framing and mark up what is missing.