How to Run Cat6 for Cameras Through a Finished House

Why this matters

In a finished house the cable path is the job. The cameras take an hour to hang; the runs take the day, and they are where the damage happens: a hole in the wrong drywall, a staple through a jacket, a cable sharing a bay with the porch light circuit, a firestop left open between the garage and the house. Most of those are invisible once the patch is painted, and they surface later as a camera that drops video or an inspector's note. This card is how to get each cable from its camera spot to the recorder through framing you cannot see, without leaving anything behind that a second visit has to fix.

Choosing the spots is in How to Plan Camera Locations on a House. Making the ends and reading the tester is in Terminating and Testing an Ethernet Cable. This card is the part in between.

Before you start: the attic, the walls and the dust

Attic. Step only on joists or on boards laid across them; drywall between joists will not hold a foot. Roofing nails come through the deck above your head, so wear a bump cap. Attics in warm months get hot enough to cause heat illness within a short shift: run attic work in the morning, carry water, and have someone check on whoever is up there. Fiberglass irritates skin, eyes and airways; long sleeves, eye protection and a filtering facepiece worn under your shop's respirator program. Loose gray-brown, shiny, pebble-like fill is likely vermiculite, which can contain asbestos: do not disturb it, stop that route, and tell the customer it needs testing before anyone works in it.

Wiring you did not install. Treat every cable in a bay as live. Knob-and-tube wiring (single conductors on porcelain knobs) is energized and has no ground; do not move it, bundle with it or fish across it. Before drilling a plate, look along it for cables already stapled across your drilling spot.

Dust. Drilling a plate from below in a basement sends sawdust and whatever has collected on the plate into your face: eye protection every time.

Step 1: Plan every run from the recorder outward

Start at the recorder and work out to each camera, writing each route down: the space it travels (attic, basement, closet, wall bay), every plate or floor it crosses, and anything it must avoid. Home-run every camera to the recorder or its switch; a daisy-chain or a splice in the attic has no place in a camera run.

The easy paths to look for: stacked closets (an upstairs closet directly over a downstairs one), a plumbing chase, the wall bay beside a stair stringer, a basement ceiling that is still open. The paths to avoid: a framing cavity used as a return-air path (a joist space panned off to carry air back to the furnace carries return air; plenum-rated cable or a different route is the safe call, and whether code requires it there depends on how your jurisdiction applies NEC 300.22 to dwelling joist spaces), and any bay already holding a power cable along its length.

Why first: a route that dead-ends at a blocked bay halfway through a pull costs more than an hour of planning, and it is usually discovered with a hole already in the wall.

Step 2: Measure each route and check the length budget

Measure along the path the cable will actually take, including every rise and drop, and add the service loops from step 6. The Ethernet limit under TIA-568 is a 100 m channel: up to 90 m of permanent cable in the walls plus up to 10 m of patch cords. A shop default of flagging any run over 80 m leaves room for the measuring error that every attic produces.

Why: a run past the limit may still pass a basic continuity test and then drop frames, or drop power to a PoE camera that draws hard at night.

Step 3: Choose the cable for the space it passes through

Solid-copper Cat6, not copper-clad aluminum, which has higher resistance and heats under PoE. A riser-rated jacket (CMR) suits walls, floors and attics in a house. Plenum-rated (CMP) is for air-handling spaces. Any section exposed outdoors needs a jacket rated for sunlight and water, which an indoor jacket is not.

Step 4: Find the bay, then drill the plate

From the attic you drill down through a top plate; from a basement you drill up through a bottom plate. The work is finding the right bay from the other side of the plate: measure off something visible from both sides (an outside wall, a plumbing vent, a duct boot), or drill a small locator hole from the room side behind where trim or a cover plate will hide it, and push a wire through to mark it.

The full technique, including holding the bit vertical so it does not exit into the room, notching limits and restoring the plate, is in How to Drill a Top Plate and Restore It. One point that matters here: a hole through a top plate or a floor is an opening between stories, and fireblocking rules require it to be sealed around the cable with an approved material (IRC R302.11, as adopted by your jurisdiction).

Step 5: Keep your cable away from power

The NEC keeps communications and Class 2 cables out of the same boxes and raceways as power conductors except where it specifically allows it (the low-voltage articles, Article 725 and the communications articles in the 800 series, as adopted by your jurisdiction; numbering moved in the 2023 edition, so check the current one). Good practice goes further than code: do not share a drilled hole with a power cable, do not choose a bay that has a power cable running its length when the next bay is open, and cross power at right angles rather than running beside it. Code is about safety; the extra distance is about not having to troubleshoot a camera that only fails when the dimmer is on.

Step 6: Pull gently, support loosely, leave a service loop

Pull with steady tension, not a jerk; TIA-568 caps pulling tension on 4-pair cable at 25 lbf, which is less than most people expect. Keep bends to at least four times the cable's diameter, and never kink it around a plate edge. Support the cable with fasteners made for data cable, snug but not tight, and never drive a staple over it: a flattened or pierced jacket changes the pair geometry, and the run may pass continuity and fail at speed.

Leave a loose service loop of about 3 ft at each end (a shop default), coiled in the attic near the camera and at the recorder, so the cable can be re-terminated twice without a new pull. Count it in the length.

Step 7: Label, terminate, test, then close up

Label both ends with the same run number before cutting. Terminate and test every run, end to end, before any patch, insulation or fireblock goes back. A tone-and-continuity tester proves only that each wire reaches the right pin; a qualification tester (one that tests whether the run will carry the speed) catches a crushed or nicked run that continuity passes. Testing after the wall is patched breaks the physical order of the job: a failure then means opening the patch you just made.

A three-camera house, run by run

A two-story house with a basement, recorder on a shelf in the basement mechanical room. Three cameras: a rear soffit camera on the main attic, a driveway camera on the soffit of the attached garage, and a front-door camera in the porch ceiling. The porch has its own shed roof with no connection to the main attic.

The longest, R2 at 40 m, is well under the 80 m flag and the 90 m permanent-link limit, so length is not a question on this job.

R1 and R2 share everything below the main attic, and every place they pass from one space to another is an opening to seal after the test:

 garage attic    |  main attic
 cam R2 ---------+--------+---------- cam R1
 on soffit       |        |           rear soffit
 garage-house    |        | R1 + R2 drop together
 wall: crossing  |        | upstairs hall closet
 sealed, fire-   |    ----+---- floor, fireblocked
 rated sealant   |        | downstairs coat closet
 garage          |    ----+---- floor, fireblocked
                 |        |
 =========================+==== basement ceiling
   recorder <-------------+

R1. The upstairs hall closet sits over the downstairs coat closet. The crew drilled down at the back corner of each closet floor and dropped the cable inside the closets, behind a small paintable raceway, rather than fishing two stories of finished wall. Both floor holes were fireblocked after the test.

R2. The wall between the attached garage and the house is a required fire separation (IRC R302.6, as adopted). The cable crossed it through one hole sized for the cable, and after testing the gap was sealed with a fire-rated sealant. Leaving it open would put a gap in the one wall in the house meant to stop a garage fire.

R3. The bay right beside the front door held the 120 V cable feeding the porch light switch. The crew went one bay over, on the hinge side, drilled up through the bottom plate from the basement and fished to the top of the first-floor wall, then out through the wall into the porch ceiling cavity with the hole sloped down toward the outside so water drains out rather than in.

The test that failed. R1 and R2 passed wiremap and the qualification test at speed. R3 failed: the tester reported a short on one pair about 3 m from the porch end. The porch ceiling cavity was still open, and a staple driven by the crew to hold the cable to a ceiling joist had gone through the jacket. TIA-568 cabling does not allow a splice in a permanent link, and 19 m of cable is cheaper than a camera that drops out in damp weather, so R3 was pulled again with cable clips instead of staples. The new run passed.

Why the order saved the day. The porch ceiling was not yet closed when R3 was tested, so the fix was one re-pull. Had the porch ceiling been patched first, the fix would have included a second patch.

Close-up and finish test

After every run passes: fireblock each plate and floor hole, seal the garage separation penetration, pull insulation back over attic work, patch locator holes, and vacuum the dust. Then the finish test: every run passes a qualification test end to end, from the camera-end plug to the recorder-end plug, with the result saved or printed and filed on the ticket by run number. A run labeled at both ends and recorded with its length and its test result is one the next tech can trust without retesting.

References

• TIA-568 cabling standard: 100 m channel, 90 m permanent link, 25 lbf pull limit, bend radius, no splices in a permanent link
• NFPA 70 (NEC) Article 725 and the 800-series communications articles, as adopted by your jurisdiction
• IRC R302.11 fireblocking and R302.6 dwelling-garage separation, as adopted by your jurisdiction
• See related: How to Drill a Top Plate and Restore It
• See related: Terminating and Testing an Ethernet Cable