How to Install Recessed Power and Cable Behind a Wall TV
Why this matters
The wall-TV install electricians most often find is a hole in the drywall behind the screen and the TV's own cord pushed down the stud bay to a receptacle near the floor. It looks clean, it works, and it is not allowed: NEC 400.12 (2023, 2020 where the section moved, as adopted) does not permit flexible cord run through holes in walls or concealed inside them. A cord in a wall has no protection from a drywall screw, no listing for the enclosed heat, and nobody knows it is there. The customer called a TV installer first; they call the electrician to do it properly, or after the inspector at their home sale flags it. The proper version takes one recessed box, one cable and an hour.
Safety first
De-energize the source circuit. The new box is fed from an existing receptacle, so that circuit's breaker is opened, locked and tagged per 29 CFR 1910.333(b)(2), and every conductor in the source box is proved dead with a CAT III or better meter tested on a known live source before and after, per NFPA 70E Article 120 (120.5 in the 2021 edition, renumbered in 2024).
Cutting into the wall. Before cutting the drywall at the TV location, scan the bay for existing cable, plumbing and gas piping, and cut shallow with a drywall saw rather than an oscillating tool driven full depth. Wear eye protection for overhead and at-face cutting; drywall dust is a respiratory irritant, so use a dust shroud or a vacuum at the blade, and if the wall is plaster in a house built before 1978, treat the paint as lead-containing until tested and control the dust under the shop's lead-safe practices.
Ladder work at the high box is a stepladder set fully open and locked, never the top step.
What goes in the wall instead of the cord
Option A: a listed in-wall power kit. A recessed receptacle box behind the screen connected by a cable to a recessed power inlet near the floor; a short jumper cord plugs from a nearby receptacle into the inlet. It needs no work on the branch circuit, and its listing is what makes the in-wall cable legal. Install it exactly as its instructions say, with its own parts.
Option B: extend the branch circuit. Fish NM cable from a nearby receptacle up the bay to a recessed receptacle box behind the screen. This is the electrician's version, it carries no jumper cord, and it is the job this card walks.
Either way, low voltage gets its own path. HDMI, network and speaker cables go through a separate recessed low-voltage plate or box at the screen and another at the media console, never through the power box. The separation rules for Class 2 and communications cables (Article 725, reorganized with Article 722 in the 2023 edition; Article 800 for communications) keep them out of an enclosure with power conductors unless a listed barrier divides it. A two-compartment recessed box with a factory barrier satisfies both in one cutout.
Steps 1 and 2: Locate the mount, then the box
1. Hang the plan, not the TV. Mark the mount's wall plate position from the customer's chosen screen height and the mount's sheet, and mark the screen's outline on the wall in painter's tape. Everything you install must land inside that outline and clear of the mount's plate and arms.
2. Find the bay. Use a stud finder and confirm with a small probe hole. The ideal bay holds both the source receptacle and the new box, so the cable never crosses a stud. If the source is in another bay, a bore through a stud behind the drywall is fishing work; see related: Old-Work Box and Fishing Standard. Check the bay for fire blocking at mid-height (a probe wire dropped from the high cutout finds it); blocking has to be bored and the bore sealed, not removed.
Step 3: Check the source before you commit to it
What the circuit already carries. Living rooms are usually on a 15 A general circuit with other rooms on it. A TV and a sound bar draw an amp or two; a circuit that already carries a window air conditioner or a space heater is not where you add an outlet. Clamp the circuit with its normal loads running, or list them with the customer.
Box fill in the source box. Adding a cable adds two insulated conductors (the ground joins the existing ground allowance). See related: Box Fill Worked Counts for Common Boxes.
Protection the extension triggers. Extending a branch circuit to a new outlet in a living room brings in AFCI protection under NEC 210.12(D): a combination AFCI breaker at the panel, or an outlet branch-circuit AFCI receptacle at the first receptacle outlet of the existing circuit, which may not be your source box. The short-extension exception does not apply, because you are adding an outlet. The new receptacle is tamper-resistant (NEC 406.12). The full extension procedure, and the AFCI and GFCI choices it forks into, belongs to its own card; see related: How to Add a Receptacle off an Existing One.
Step 4: Cut, fish, and set the boxes
Cut the high opening for the recessed box to its template, inside the screen outline. Cut the low-voltage openings. Fish the NM from the high opening down to the source box, leaving at least 6 in of free conductor in each box (NEC 300.14). Install the recessed box with its old-work ears or clamps, the cable secured by its clamp.
Step 5: Make up both ends
At the source: pigtail hot, neutral and ground so the existing device and the new cable both come off splices rather than off the device's second set of screws; see related: How to Make Device Terminations That Last. At the new box: a 15 A or 20 A tamper-resistant receptacle matched to the breaker, torqued to its marked value with a calibrated tool (NEC 110.14(D)).
The worked example: depth decides the box
A customer is hanging a 65 in TV on a low-profile mount. Say the mount sheet gives 1.40 in from the wall to the back of the TV, and the TV's own cord has a straight plug whose body, measured on the bench, stands 1.10 in off the receptacle face, with another 0.50 in before the cord can turn without kinking.
DEPTH STACK-UP (inches, from the wall surface)
available: wall to back of TV (mount sheet) 1.40
plug body: receptacle face to plug back 1.10
cord bend beyond the plug back 0.50
plug + bend: 1.10 + 0.50 1.60
STANDARD BOX, receptacle face 0.10 proud
needed in front of wall: 0.10 + 1.60 = 1.70
1.70 against 1.40 available: FAIL by 0.30
RECESSED BOX, receptacle face 1.50 back
needed in front of wall: 1.60 - 1.50 = 0.10
0.10 against 1.40 available: PASS, 1.30 spare
A standard box would press the plug against the back of the TV, which is how a plug blade cracks or a cord jacket wears through at the bend. The recessed box (its sheet gives 1.50 in of recess) swallows the plug and most of the bend.
The rest of the job, carried through. The source receptacle is 16 in above the floor in the same bay, a 15 A circuit of 14 AWG. Its box is an old plastic single-gang marked 18.0 cu in, the end of its run with one 14/2 cable. Before: 2 conductors, 2 device allowances, 1 ground allowance, 5 x 2.0 = 10.0 cu in. After adding one 14/2: 4 + 2 + 1 = 7 allowances, 7 x 2.0 = 14.0 cu in, under 18.0, pass. With its normal loads running the circuit clamps at 3.2 A, and the TV and sound bar add about 2 A, well under the 15 A breaker. Because the source is the last outlet on the circuit, an outlet branch-circuit AFCI would have to go at the first outlet, a bedroom receptacle two rooms away; the panel accepts a combination AFCI breaker, so the circuit's breaker is replaced with one instead. The new box takes a 15 A tamper-resistant receptacle.
What would change the answer. A TV with a right-angle plug that sits 0.60 in deep, plus no bend allowance, gives 0.10 + 0.60 = 0.70 in needed with a standard box, inside 1.40 in, and a standard box would do. A source box marked 14.0 cu in would be at its limit after the extension (7 allowances x 2.0 = 14.0 cu in), and any internal clamp would push it over, so it would be swapped for a larger old-work box first. A source in a bathroom or kitchen is not used at all: those circuits are restricted to their rooms.
Finish test: the plug fits flush behind the mount
- Remove the lock and tag, then restore power standing to the side of the panel face. Test the AFCI with its test button.
- Meter the new receptacle: hot to neutral about 120 V, hot to ground about 120 V, neutral to ground near zero. See related: How to Check Receptacle Wiring with a Meter.
- Plug the TV's own cord in with the mount's plate installed, then lower the TV onto the mount. The back of the TV must not touch the plug or cord: slide a business card between them at the plug and it should pass freely. Run the TV for a few minutes and confirm it powers on.
- Confirm nothing flexible is concealed: the only cords left are the TV's own cord inside the recessed box and the low-voltage leads in their own plates.
- Record the source box fill, the circuit loading, the AFCI method and the location of the new cable on the ticket.
References
- NFPA 70, National Electrical Code, 2023 edition (2020 where the section moved), as adopted by your jurisdiction: 110.14(D), 210.12(D), 300.14, 400.12, 406.12, Articles 722, 725 and 800
- NFPA 70E, Standard for Electrical Safety in the Workplace, current edition, Article 120; 29 CFR 1910.333
- Recessed box, in-wall power kit and TV mount manufacturers' instructions
- See related: How to Add a Receptacle off an Existing One; Old-Work Box and Fishing Standard; Box Fill Worked Counts for Common Boxes