Hide Wires Inside Fireplace Bump-Out (Chase Tubes)

To conceal TV and speaker wires in a fireplace bump-out, use a dedicated, accessible chase outside the fireplace enclosure, vent path, and required clearance zones. Follow the appliance manual and locally adopted codes. Use wiring rated for concealed spaces, separate power from low-voltage cables, protect wiring at framing, and restore any fireblocking before closing the wall.

A clean fireplace wall can make a room feel finished. A bundle of cords running down its face can undo that effect. The challenge is that a fireplace bump-out is not always ordinary wall space: it may contain a vent, hot-air passage, or parts of the appliance’s protected zone.

I start by treating the bump-out as a small, mapped construction space, not a convenient place to fish cables. A route that looks clear from the room may still conflict with the fireplace’s listing or instructions. The steps below help you plan a concealed route without guessing about heat, clearance, or code.

Planning: Identify the Appliance, Code Edition, and Route

Before cutting or drilling, identify what is inside the bump-out and what rules apply. The appliance manual defines its required clearances and any permitted wiring zones; the adopted electrical and building codes, local amendments, and inspector determine the installation requirements.

Record the fireplace make and model, fuel type, vent route, access panels, framing, and existing wires. Get the installation manual for that exact model. Do not borrow a clearance number from another fireplace, or assume that a material’s heat rating makes it safe in a prohibited zone.

Then map the proposed chase from the TV location to an accessible point below or beside it. The tube must remain outside the appliance enclosure and vent or chimney space. Note bends, framing, fasteners, and where a cable will enter and exit. If the route cannot be confirmed from plans or safe access, pause and ask a qualified installer or the local inspector to review it.

First decision: If the proposed tube crosses a clearance zone, vent path, convection passage, or appliance enclosure, do not use that route. Find another route or obtain a qualified review.

Access and Clearances: Keep the Chase Outside Protected Zones

A chase is a dedicated path for wires or raceway. It may be built into the bump-out, but it must not borrow space from the fireplace’s protected areas. Keep the path accessible enough to inspect and pull cables, and preserve required clearances and airflow.

A bump-out can hide more than framing. Some fireplaces use air passages around the firebox to move room air; others have venting or chimney components within the surrounding structure. A cavity that appears empty may be part of one of these systems. The manual’s clearances and restricted zones control, even if a cable or tube is rated for heat.

Plan access at both ends of the route. Avoid tight turns that make future cable replacement difficult, and do not cover an access panel or service opening. If the tube is a raceway, its type and fittings must be suitable for the location and exposure. A loose plastic tube is not automatically a permitted raceway or a safe choice near a heat source.

Route option	Best fit	Main checks
Dedicated tube in a separate wall bay	Signal cables such as HDMI or Ethernet	Keep out of vent and clearance zones; use suitable cable and accessible ends
Separate raceway for power wiring	A permitted concealed power route	Use an approved wiring method, suitable raceway, and required separation from communications wiring
Surface-mounted raceway outside protected areas	When opening the wall is not practical	Confirm the route does not cross an appliance clearance or service area
Route through the fireplace enclosure or vent space	Not an acceptable shortcut	Do not drill, fish, or route through these areas

The table compares planning choices, not blanket approvals. A specific fireplace manual or local rule may rule out a route that appears workable.

Execution: Separate, Support, Protect, and Fireblock

A concealed chase needs the right wiring method, separate paths for power and signal, and protection where wires pass through framing. Restore fireblocking wherever work opens a concealed space. These steps reduce damage and code risks, but they do not make a route acceptable if it conflicts with the fireplace instructions.

Use wiring made for concealed installation

A TV’s detachable power cord, extension cord, or ordinary appliance cord is not a substitute for permanent wiring inside a wall or chase. Do not fish one through the bump-out. Use a wiring method approved for the concealed location and installation, or a listed power relocation system installed as its instructions require.

For TV signals, choose cables with markings and ratings suitable for the concealed space and the local code. Check the specific cable type and the pathway’s temperature exposure. A low-voltage label alone does not confirm that a cable is suitable for every wall, ceiling, or fireplace-adjacent space.

Keep power and signal wiring apart

Line-voltage conductors and communications or Class 2 cables must not share an ordinary, unpartitioned tube. NEC 725.136 sets separation rules for Class 2 wiring, with specific conditions and permitted methods. Use separate raceways or another method that meets the adopted code; do not assume that a small gap inside one open tube is enough.

Keep the routes distinct from the planning stage. This also helps prevent cable crowding and makes later service work clearer. If using a power relocation kit, follow its listed instructions for the power path and keep signal cables in a separate, compliant route.

Protect framing and restore fireblocking

Where a cable passes through a wood framing member less than 1¼ inches from the nailing face, NEC 300.4(A)(1) requires protection with a listed steel plate at least 1/16 inch thick or equivalent. This helps protect the cable from nails or screws. Place protection wherever the rule applies, not only where a cable’s path is easy to see.

Fireblocking limits the movement of fire and smoke through concealed spaces. Under the adopted IRC, R302.11 calls for fireblocking at specified locations, including floor and ceiling levels and, in applicable vertical concealed spaces, at intervals no greater than 10 feet. Seal disturbed openings with approved fireblocking materials. Confirm local requirements, since the adopted code edition and amendments may differ.

If the tube is being used as a raceway, size it for the wires and raceway type. NEC Chapter 9, Table 1 generally limits raceway fill to 40% when there are more than two conductors. The applicable calculation depends on what is being installed; verify conductor count, raceway type, and any relevant exception rather than estimating by eye.

Before closing: Check that the route is supported and terminated as required, cables are protected at framing, power and signal remain separated, and every disturbed fireblock is restored.

Real-World Layout Examples

These examples are common planning scenarios, not reports of specific customer installations. They show how I assess a route; the fireplace manual and local requirements still determine whether a particular design is allowed.

Example 1: TV above a direct-vent gas fireplace. The TV and fireplace share a bump-out, but the vent and appliance clearances occupy part of it. I would first locate those zones from the exact manual, then look for a separate wall bay that can carry a signal tube without crossing them. If no safe path exists, I would not force a route behind the firebox.

Example 2: Media wiring and power both need concealment. A homeowner wants HDMI, Ethernet, and TV power in one tube. I would plan separate paths: one for communications wiring and another approved method for power. Combining them in an ordinary shared tube is not the solution, even if the tube seems large enough.

Example 3: The bump-out has an accessible side panel. An access panel can help with cable pulls and inspection, but it does not make the cavity behind the fireplace available for wiring. I would confirm the panel’s purpose, preserve its operation, and trace the appliance and vent boundaries before choosing a route.

Verification: Inspect Before Closing and Confirm Appliance Operation

Before drywall or trim hides the work, verify the path against the fireplace manual and applicable code. Photograph the open chase, cable labels, framing protection, and fireblocking. These records can help during inspection or future service, but they do not replace required inspections.

Use this close-out check:

• The tube stays outside the enclosure, vent path, and required clearance zones.
• Power and low-voltage wiring use separate, compliant paths.
• The raceway and cables suit their location, exposure, and installation.
• Required nail plates and other cable protection are in place.
• Disturbed fireblocking is restored with approved materials.
• Cable ends and any access panels remain reachable.
• Bends and fill allow the intended cables to be pulled without damage.
• Required electrical or building inspections are complete.

Only operate the fireplace after confirming that the work does not affect its listing, venting, airflow, clearances, or service access. If the route’s safety depends on a guess about what a cavity contains, stop and have it checked before closing the wall.

Frequently Asked Questions

Can I run TV wires behind a fireplace bump-out?
Only if the route is outside the appliance enclosure, vent path, and required clearance zones, and meets the manual and local code. The bump-out is not automatically safe for wiring.

Can HDMI and power wires share one chase tube?
Not in an ordinary unpartitioned tube. Use separate raceways or a separation method that complies with the adopted code, including NEC 725.136 where applicable.

Can I hide a TV power cord inside the wall?
Do not conceal an extension cord or ordinary appliance cord as permanent wiring. Use an approved wiring method or a listed power relocation system installed according to its instructions.

How much clearance does a fireplace need from wiring?
There is no universal clearance. Use the exact fireplace model’s manual and listing, plus local code requirements. Do not infer clearance from another appliance or from a cable’s temperature rating.

Can I drill through the fireplace enclosure to make a cable route?
No. Do not drill or route through the enclosure, vent, chimney space, or required clearance zone. Choose a separate path outside those protected areas.

Does a plastic tube count as a raceway?
Not automatically. The tube must be listed and suitable for its use and location if it is serving as a raceway. Confirm the product, fittings, and installation against the applicable code.

When are nail plates needed?
Under NEC 300.4(A)(1), protect a cable passing through framing when it is less than 1¼ inches from the nailing face, using a listed steel plate at least 1/16 inch thick or equivalent.

Do I need fireblocking in a fireplace bump-out?
Openings in concealed spaces may need fireblocking under the adopted building code. Where IRC R302.11 applies, requirements include specified floor and ceiling locations and, in applicable vertical spaces, intervals no greater than 10 feet.

What should I do if I cannot tell where the vent or clearance zone is?
Do not cut or fish the cable. Find the exact appliance manual and trace the route, or have a qualified installer or local inspector review it before work proceeds.

Should I close the wall before inspection?
No. Photograph and verify the concealed work first, and complete any required inspections before closing it. This lets the wiring, protection, separation, and fireblocking be checked while visible.

(This article was written by one of our staff writers, Michael Holloway. Visit our Meet the Team page.)