Hide Ethernet Cables Between Rooms (Door Jamb Notch)
To conceal Ethernet between rooms, do not run it through the door’s moving gap or cut a door, frame, or structural member by guesswork. First confirm what is rated and what is behind the trim, then choose a protected route. Keep the cable’s bend and power separation, restore fire protection where needed, and test both the door and network.
If you are looking ahead to a cleaner room, a small notch under door casing may seem like a simple fix. But the visible trim can hide a door frame, wiring, or part of a rated assembly. The safer goal is not simply to make the cable disappear. It is to conceal it without trapping it, weakening the opening, or changing how a fire or smoke barrier works.
I have found that the key decision comes before any cutting: identify exactly what the proposed route would pass through. There is no universal, code-approved door-jamb notch size. Local rules, the cable instructions, and the door and wall assembly all matter.
Plan the Route and Identify Rated Construction
A route plan identifies the parts the cable would cross and any limits on altering them. Before removing trim or cutting, determine whether the door, frame, or wall is fire-rated, and check for framing, utilities, and fireblocking. If you cannot confirm the assembly or route, pause and ask a qualified installer or building official.
Start by checking building records, labels on the door or frame, and any information from the property owner or building manager. A label may identify a listed fire door. Do not remove, cover, or damage it. In a rental, get permission before removing trim or making any permanent change.
Next, inspect both rooms and the full opening. Look for outlets, switches, visible pipes, and signs that the wall contains wiring or plumbing. A stud finder can help locate framing, but it does not reliably identify every hidden service or establish that a route is safe. Use suitable inspection methods before drilling.
A notch can involve more than decorative casing. The casing is the visible trim around the door. Behind it may be the door frame, also called the jamb, which holds the door and its hardware. Cutting the frame, door, or structural framing based on an assumed allowance is not a safe shortcut.
Where practical, consider these route options before choosing a notch:
- Use an existing communications pathway, if it is suitable and has room.
- Run cable through an appropriate wall cavity, with required protection and firestopping.
- Use a surface raceway along the wall and above the opening when concealed routes are unsuitable.
- Consider a carefully planned path behind removable casing only if it avoids the frame and does not crush the cable when the casing is refitted.
The best option depends on the building. In a rated wall, a cable penetration may require a firestop system designed for that assembly. The International Building Code addresses fire-resistance-rated construction in Section 714, while NEC 300.21 addresses fire stopping around penetrations. The locally adopted code and approved assembly details govern.
Check Door Operation, Cable Bend, and Required Clearances
A cable path is acceptable only if it stays clear of moving and compressing parts and preserves the cable’s shape. Check the door through its full swing, including the latch side, hinges, seals, and floor clearance. Do not rely on a door closing as proof that the cable is safe.
A door can close and still pinch a cable. Do not route Ethernet through the operating gap between the door and frame, under the door, or through weatherstripping. These areas move or compress when the door closes. A cable trapped there can be damaged, and a gap or seal may serve a ventilation, smoke-control, or fire-safety purpose.
Check the cable’s bend radius, meaning the tightest curve it can make without risking performance. For UTP (unshielded twisted-pair) cable, a general installation minimum is a bend radius of at least four times the cable’s outside diameter. Follow the cable manufacturer if it calls for a larger radius. Do not kink, sharply fold, or pull the cable tight around a corner.
| Route or condition | What to check | Practical decision |
|---|---|---|
| Behind removable casing | Is it trim only? Can the cable lie without being pinched when casing is refitted? | Consider only if the frame and rated parts remain untouched. |
| Through a wall | Is the wall rated? Are framing, utilities, and fireblocking identified? | Use an approved route and restore required protection. |
| Across a door gap or undercut | Will the door, seal, latch, or foot traffic press the cable? | Avoid this route. |
| Near power wiring | Is required separation maintained or an applicable exception used? | Check local code and the conditions for any exception. |
| Through framing | Does the hole or notch leave less than 1¼ inches to the framing face? | Where IRC R602.6 applies, install the required code-compliant steel protection plate; this does not authorize an improper notch. |
NEC 800.133(A)(2) generally calls for 2 inches of separation between communications cable and electric-light, power, Class 1, and non-power-limited fire-alarm conductors. The code includes exceptions, such as certain approved barriers or raceways. Confirm the adopted NEC edition and the conditions that apply rather than treating the distance as a universal rule for every installation.
Install and Protect the Concealed Cable Path
Install only after confirming the route and selecting cable suited to its location. Support it without crushing, preserve its bend radius, and protect it from fasteners and sharp edges. If the path crosses a rated assembly, follow an approved detail and use firestopping appropriate to that assembly.
Choose the cable. Use communications cable listed for the space and conditions where it will run. For example, spaces used to move environmental air can have specific cable requirements. Check the cable marking, local code, and manufacturer’s instructions; do not assume an ordinary indoor cable is suitable for every concealed space.
Prepare the route. If removing casing, work carefully and avoid prying against the frame. Before drilling, verify the other side of the surface and the likely path of hidden services. Do not drill or notch structural framing unless the method is allowed by applicable rules and the building’s construction details.
Protect the cable. Keep it away from sharp edges and fasteners. Where a hole or notch leaves less than 1¼ inches between the cable path and the framing face, IRC R602.6, where adopted, calls for a code-compliant protective steel plate. That plate helps protect against nails and screws; it is not permission to cut a stud or other structural member.
Maintain separation and support. Keep the cable away from power conductors as required by the locally adopted NEC. Use only supports and fastening methods suited to communications cable, and do not staple or cinch it so tightly that the jacket or cable geometry is damaged.
Restore the assembly. If the route penetrates a fire-rated wall or another rated assembly, use a firestop system appropriate to that specific construction. Do not fill the opening with an arbitrary material and assume it restores the rating. If you cannot identify a suitable approved detail, stop and get guidance.
A notch in decorative trim may be possible in some situations, but there is no reliable standard dimension to copy. The cable must fit without compression, keep its bend radius, and avoid the frame and other protected parts. If those conditions cannot be met, use another route.
Finish, Restore Fire Protection, and Verify Operation
Finishing means more than hiding the cable from view. Refit the trim without pinching the cable, restore any required fireblocking or firestop, and test the door and network. A successful Ethernet connection does not show that the cable is undamaged or that a rated assembly remains intact.
Before closing the route, take a clear photo of the cable path for future repairs. Refit casing without forcing it over the cable. Then open and close the door through its full swing and confirm that the latch, hinges, seals, and floor clearance work as before. Look for any sign of pressure or scraping along the cable.
Test the Ethernet link at both ends. A link light or connection is a useful check, but it does not replace a visual inspection for crushing, sharp bends, or damaged insulation. If the cable passes through a wall, verify that any required firestop or fireblocking has been restored with a compatible method.
Two common situations show why the route matters:
- Trim-only route: A homeowner wants to cross a doorway between rooms. Inspection confirms the proposed channel would involve only removable casing, not the frame, and the cable can sit without pressure. The casing is refitted carefully, then the door and link are tested. If any part of the frame would need cutting, this approach is abandoned.
- Rated opening: A renter finds a label on the door and cannot confirm whether the frame or wall is part of a rated assembly. Rather than notch the opening, they ask the property manager about an approved pathway or use a permitted surface raceway. The label and assembly stay intact.
The practical takeaway is simple: use a trim route only when it truly stays in trim and leaves the cable uncompressed. Otherwise, choose a protected wall route or a surface raceway, and confirm the building requirements before altering anything.
Frequently Asked Questions
These answers cover common decisions when routing Ethernet between rooms near a door. The right choice depends on the cable, the door and wall construction, and locally adopted rules. If a rated assembly or structural member may be involved, verify the approved route before cutting.
Can I notch the door jamb for Ethernet cable?
Do not notch the frame by assumption. A small cut can alter a rated or structural part. There is no universal approved notch size.
Can I notch only the door casing?
Possibly, if it is truly decorative trim, the frame remains untouched, and the cable will not be crushed when the casing is refitted.
Can I run Ethernet under a door?
Avoid it. The door or floor can pinch or damage the cable, and the gap may be needed for a seal, ventilation, or smoke control.
What bend radius should I use?
For UTP cable, use at least four times its outside diameter as a general minimum. Follow the cable maker if it specifies a larger radius.
How far should Ethernet be from power wiring?
NEC 800.133(A)(2) generally requires 2 inches of separation, subject to stated exceptions. Check the adopted edition and installation conditions.
Does a steel nail plate make any framing notch acceptable?
No. Where IRC R602.6 applies, a plate protects against fasteners when the specified spacing is lacking. It does not approve an otherwise improper structural cut.
Can I drill through a fire-rated wall?
Only with an appropriate approved detail and required firestopping. Confirm the wall’s rating and local requirements before making a penetration.
How do I know if the door or frame is fire-rated?
Look for labels and check building records or ask the property manager. If you cannot confirm the rating, do not cut the door or frame.
Is a surface raceway a safe alternative?
It can avoid cutting the door or wall, but it still needs a suitable route and secure installation. Keep it clear of the door’s moving parts and follow product instructions.
How do I verify the job is finished correctly?
Inspect for pinching and sharp bends, confirm required fire protection is restored, operate the door fully, and test the Ethernet connection at both ends.
(This article was written by one of our staff writers, Michael Holloway. Visit our Meet the Team page.)
