How to Wire a Switched Half-Hot Living Room Receptacle
Why this matters
A living room with no ceiling light still needs a switch at the door that turns on a light, and the cheapest compliant way to give it one is a receptacle with its top half on the switch and its bottom half always live. Done right, a floor lamp comes on from the doorway and the TV on the same receptacle never loses power. Done carelessly, it produces one of three calls: the switch does nothing, the switch kills the router plugged into the "wrong" half, or one half is dead all the time because someone broke the wrong tab.
All three are wiring decisions made at the box, and all three show up on a two-minute test before the plate goes on. Code citations below are NEC 2023 (2020 where the section moved), as adopted, local amendments checked.
What the code allows and what it does not ask for
The allowance. NEC 210.70(A)(1) requires at least one wall-switch-controlled lighting outlet in every habitable room, kitchen and bathroom of a dwelling. Its Exception No. 1, in substance, lets one or more receptacles controlled by a wall switch stand in for the lighting outlet in rooms other than kitchens and bathrooms. A living room qualifies; a kitchen or bathroom does not, and there the switched light is mandatory. See related: Required Lighting Outlets and Switch Locations.
The spacing question. NEC 210.52, as adopted, says the receptacles that section requires are in addition to a receptacle controlled by a wall switch under that 210.70 exception. Whether the always-on half of a split receptacle still counts toward the wall spacing is read differently by different inspectors. The shop default: lay out the 6 and 12 ft spacing as if the switched receptacle were not there, or ask the inspector before rough-in and write the answer on the plan. See related: Dwelling Receptacle Spacing: The 6 and 12 Foot Rule.
The marking. The controlled-receptacle marking in NEC 406.3, as adopted, is written for receptacles under automatic control (energy management and building automation), not for one on an ordinary wall switch, so the code does not require marking this one. The shop marks it anyway, because the customer cannot see which half the switch controls and will plug the router into it. Use a permanent mark on the device face or plate at the switched half, and tell the customer in words which half it is.
Which half. This shop switches the TOP half, on every split receptacle in every house, so a customer who learns one has learned them all. Pick a convention and keep it; a house where the top half is switched in one room and the bottom in the next is the version that generates calls.
The wiring, box by box
SWITCH BOX RECEPTACLE BOX
feed 14/2 from panel 14/3 from switch box
BLK -+---> SW ---- RED ------> top brass (SWITCHED)
| ..hot side tab BROKEN..
+-------- BLK -------+--> bottom brass (always on)
+--> BLK out to next recept.
WHT ---------- WHT -------+--> silver (tab INTACT)
+--> WHT out to next recept.
BARE -+--> SW green BARE-+--> green screw
+--> 14/3 bare +--> BARE out
The feed lands in the switch box. The 3-wire cable carries the always-on black, the switched red and the neutral to the receptacle. The circuit continues to the rest of the room's receptacles from the receptacle box, taken off the always-on black through a pigtail.
Why the hot-side tab breaks and the neutral-side tab does not. The tab between the two brass screws joins the halves on the hot side. Break it and the top screw (red, switched) and bottom screw (black, always on) become two separate supplies. Both halves still return on the same neutral, because both are on the same circuit, so the silver-side tab stays whole and one neutral pigtail serves both halves. Break the neutral tab too and the half without a white conductor has no return: anything plugged into it is dead. That second mistake is the one that comes back as "half the receptacle never works."
Why the always-on black goes out on a pigtail, not on a screw. With the hot tab broken, the top brass screw is switched. A continuing black landed on the spare top screw would put every downstream receptacle in the room on the switch. Pigtail the incoming black, the outgoing black and the bottom brass screw together.
Why the neutral is in the switch box. It passes through on its way to the receptacle, spliced white to white. That keeps a neutral available at the switch for a future smart switch, and NEC 404.2(C) requires a grounded conductor at most switch locations serving lighting loads. See related: How to Get a Neutral to a Switch Box for a Smart Switch.
Box fill
Both boxes hold more than the two-wire version, and this is where the 3-wire job gets crowded. Using 2.00 cubic inches per 14 AWG conductor (NEC 314.16, as adopted):
- Switch box: feed 14/2 counts 2, the 14/3 counts 3, all equipment grounding conductors together count 1, the switch yoke counts 2. Total 8 x 2.00 = 16.0 cubic inches.
- Receptacle box: the 14/3 counts 3, the 14/2 out counts 2, grounds count 1, the receptacle yoke counts 2. Total 8 x 2.00 = 16.0 cubic inches.
A single-gang box marked 18 cubic inches passes both; a 12.5 cubic inch shallow device box does not, and it is a common old-work box. On a 20 A circuit with 12 AWG, the same 8 counts at 2.25 come to 18.0 cubic inches, exactly at an 18 cubic inch box. See related: Box Fill Worked Counts for Common Boxes.
Making it up
Isolate the circuit and prove both boxes dead. Breaker off and locked, then live-dead-live at each box on every conductor with a CAT III or better contact meter proven on a known live source before and after, per NFPA 70E Article 120 (120.5 in the 2021 edition, renumbered in 2024), work practices at 29 CFR 1910.333(b)(2), or 1926.417 on construction work. A switch box near a door often holds a second circuit's cable, so test everything in it.
Break the hot-side tab before the receptacle goes near the box. Grip the brass-side tab with needle-nose pliers and work it until it snaps off cleanly; a tab bent but not broken still conducts. Look at it on the bench, not in the box, so there is no question which side you broke. Wear eye protection; the tab can spring.
Land the receptacle. Red on the top brass screw, the always-on black pigtail on the bottom brass, the white pigtail on a silver screw, the bare pigtail on the green. Torque to the value on the device or its instructions (110.14(D)). The living room receptacle is tamper-resistant per NEC 406.12 and the circuit is AFCI-protected per 210.12; see related: Tamper-Resistant and Weather-Resistant Receptacle Rules, and AFCI and GFCI by Location in a Dwelling.
Land the switch. Feed black to one terminal, red to the other, bare to the switch's green screw. Neutrals spliced through. Fold everything back with the splices clear of the device terminals.
Mark the switched half. On the receptacle face or the plate, at the top half.
Worked example: the remodel where the switch did nothing
A 14 by 18 ft living room in a remodel had no ceiling outlet. The owner wanted the floor lamp by the window on the switch at the hall door. Circuit: 15 A AFCI breaker, 14 AWG, feed to the switch box at the door, 14/3 run 9 ft to the receptacle by the window, 14/2 on to four more receptacles around the room. Both boxes were 18 cubic inch new-work boxes, so the 16.0 cubic inch counts above passed with 2.0 to spare.
The apprentice made both boxes up, the breaker went on, and the lead ran the finish test.
First test, failed. Switch off: lamp in the top half still lit. Meter at the top half, hot to neutral: 121 V with the switch off, 121 V with it on. Bottom half: 121 V either way. The switch was doing nothing at all.
Reasoning. A switch that changes nothing means the switched conductor is tied to the always-on conductor somewhere downstream of the switch. On a split receptacle, the first suspect is the hot-side tab. A broken neutral tab would produce the opposite symptom, a dead half, and a switch landed between the feed and the always-on black would switch both halves and the rest of the room, so neither fit.
Confirmed. Breaker off, box re-verified dead live-dead-live, receptacle pulled. The brass-side tab had been bent with pliers but not snapped off, and it still bridged the two screws. Because red and black were on the same circuit, nothing tripped and nothing heated; the switch was simply paralleled out of the circuit. Had the red come from a different breaker, the bridged tab would have tied two circuits together, which is why this test is never skipped even when the symptom looks harmless.
Second test, passed. Tab removed, receptacle reinstalled, breaker on. Switch off: top half 0 V hot to neutral, lamp off; bottom half 121 V. Switch on: top 121 V, lamp on; bottom 121 V. Both halves then checked for polarity and ground with the meter, and the AFCI breaker's test button tripped the circuit and reset. The top half was marked and the owner was shown it: lamp in the top, TV and router in the bottom.
What changes the job
- The feed arrives at the receptacle, not the switch. The run reverses: 2-wire feed to the receptacle box, a switch loop to the switch. Then the switch box needs a neutral run to it anyway, so a 3-wire switch loop (black, red, white) is the usual answer; reidentify nothing.
- Both halves on the switch. Do not break the tab; land the switched red on a brass screw and continue the always-on circuit on a pigtail. The whole receptacle then serves as the lighting outlet and contributes nothing to the spacing count.
- A multiwire circuit feeding two halves from two breakers. That is a different job with its own neutral and disconnect rules, owned by How to Wire a Multiwire Branch Circuit to Split Receptacles.
Finish test
Plates on, remove your lock, stand to the side of the panel and close the breaker. Switch off: the marked half reads 0 V hot to neutral and the unmarked half reads line voltage; switch on: both read line voltage. Every downstream receptacle stays live with the switch off. Both halves pass the meter's three readings, the AFCI trips on its test button, and the plate carries the mark. The ticket records the box fill counts, the switched half, and both test results.
References
- NEC 2023 (2020 where the section moved), as adopted: 210.70(A)(1) Exception No. 1, 210.52, 404.2(C), 406.3, 406.12, 210.12, 314.16, 110.14(D)
- NFPA 70E, Article 120 (120.5 in the 2021 edition, renumbered in 2024), current edition as your safety program adopts it
- 29 CFR 1910.333(b)(2) and 29 CFR 1926.417
- See related: Required Lighting Outlets and Switch Locations
- See related: How to Check Receptacle Wiring with a Meter