To wire an outlet with a switch—specifically the highly useful "half-hot" or split receptacle where the top plug is controlled by a wall switch and the bottom plug is always on—you need a 15A duplex receptacle, a 15A single-pole switch, and 14/3 NM-B cable run from the switch box to the outlet box on a 15A breaker. The single most critical mechanical step in this entire process is snapping off the brass fin tab on the hot side of the receptacle to isolate the two halves.

This configuration is the standard for living rooms and bedrooms, allowing you to plug a floor lamp into the top half (switched) and a vacuum or phone charger into the bottom half (always hot). Below is the exact decision path, material list, and bench-tested procedure to get it right on the first try.

The Decision Path: Which Switched Outlet Layout Do You Need?

Before pulling any wire, you must decide how the switch interacts with the receptacle. The layout you choose dictates the cable type and the physical preparation of the receptacle.

Layout Type Cable Required Receptacle Prep Best Use Case
Whole Outlet Switched 14/2 NM-B None (leave tabs intact) Garage workbench, dedicated tool outlet
Half-Hot (Split) 14/3 NM-B Break hot-side brass fin tab Living room lamps, bedroom lighting
Smart Switch (Always Hot) 14/2 NM-B + Neutral None Smart plugs, WiFi-enabled lamps
Concrete Pick: For 90% of residential DIY builds, choose the Half-Hot (Split) Layout using 14/3 NM-B on a 15A breaker. It provides maximum flexibility, meets modern NEC requirements for a neutral at the switch box, and uses standard, inexpensive components.

Tools, Materials, and Device Ratings

Do not substitute gauges or device ratings. A 20A receptacle on a 15A breaker is legal, but a 15A receptacle on a 20A breaker is a fire hazard and a direct code violation. The parts list below assumes a standard 15A branch circuit.

Materials List

  • Cable: Southwire 14/3 NM-B (Romex) with ground. Rated for 15A, 600V, 90°C dry.
  • Receptacle: Leviton 15A Tamper-Resistant (TR) Duplex Receptacle (Model R52-05320-WST). Note: TR shutters are mandated by NEC 406.12 for all 15A and 20A 125V receptacles in dwelling units.
  • Switch: Leviton 15A Single-Pole Toggle Switch (Model R62-01451-WST).
  • Wire Nuts: Ideal Yellow Wing-Nuts (rated for 3x #14 AWG solid copper).
  • Pigtails: 6-inch lengths of 14 AWG THHN (Black, White, Green) for switch box grounding and neutral splices.

Tool List

  • Klein Tools 11063 Wire Strippers (10-18 AWG)
  • Non-Contact Voltage Tester (NCVT) for initial sweep
  • Fluke 117 or equivalent True-RMS Digital Multimeter (2-lead) for dead verification
  • Lineman pliers and needle-nose pliers (for breaking the fin tab)
  • Torque screwdriver (optional but recommended; target 12-14 in-lbs for 14 AWG terminal screws)

Mains Safety Protocol: De-Energize and Verify

WARNING: Lethal Voltage. This procedure involves 120V AC mains. Working on an energized panel or branch circuit can cause fatal electrocution or arc flash.
  1. Turn off the 15A branch circuit breaker at the main panel.
  2. Apply a piece of electrical tape over the breaker handle or use a physical breaker lockout device.
  3. Test your multimeter on a known live circuit (like a kitchen outlet) to prove the meter and leads are functional.
  4. Insert the 2-lead multimeter probes into the target outlet: Line to Neutral, Line to Ground, and Neutral to Ground. All readings must be exactly 0.0V.

NEC-style guidance: Your local Authority Having Jurisdiction (AHJ) has final authority. If you are unsure of your panel's condition, defer to a licensed electrician.

Step-by-Step Wiring: Power at the Switch

This procedure assumes the power source (the 14/2 cable from the breaker panel) enters the switch box first, and you are running a new 14/3 cable from the switch box to the outlet box. This is the cleanest method and complies with NEC 404.2(C), which requires a grounded circuit conductor (neutral) at nearly all switch locations.

Phase 1: Wiring the Switch Box

  1. Prepare the Pigtails: Strip 3/4 inch of insulation from your 14 AWG THHN pigtails.
  2. Grounding: Wire-nut the bare ground from the panel cable, the bare ground from the 14/3 NM-B cable, and the green ground pigtail together. Connect the other end of the green pigtail to the green grounding screw on the switch.
  3. Neutral Splice: Wire-nut the white neutral from the panel cable, the white neutral from the 14/3 NM-B cable, and the white THHN pigtail together. Do not connect the white wire to the switch. Cap the end of the white pigtail with a wire nut; this satisfies the NEC neutral-at-switch requirement for future smart switches.
  4. Line (Always Hot): Wire-nut the black wire from the panel cable and the black wire from the 14/3 NM-B cable together. This passes constant 120V power directly to the bottom half of the outlet.
  5. Load (Switched Hot): Connect the red wire from the 14/3 NM-B cable to the bottom brass terminal screw on the switch.
  6. Switch Line Input: Connect the black THHN pigtail (which you should wire-nut to the panel black and 14/3 black in step 4) to the top brass terminal screw on the switch. Note: Standard single-pole switches are not polarity-sensitive, so top/bottom brass placement doesn't affect function, but keeping Line on top is good practice.

Phase 2: Wiring the Outlet Box (The Split)

  1. Break the Fin Tab: Using your needle-nose pliers, grip the small brass fin tab located between the two brass (hot) screws on the side of the receptacle. Bend it back and forth until it snaps off. Do NOT break the silver fin tab on the neutral side.
  2. Ground: Connect the bare copper ground from the 14/3 cable to the green grounding screw on the receptacle.
  3. Neutral: Connect the white wire from the 14/3 cable to either silver terminal screw. (Because the silver tab is intact, both halves share this neutral).
  4. Always Hot (Bottom): Connect the black wire from the 14/3 cable to the bottom brass terminal screw.
  5. Switched Hot (Top): Connect the red wire from the 14/3 cable to the top brass terminal screw.
  6. Secure and Fold: Wrap the box with a single layer of electrical tape over the terminal screws (a veteran trick to prevent ground wires from shorting against exposed brass). Carefully fold the wires into the box, pushing the receptacle flush, and torque the mounting screws to the drywall ears.

The Most Common Botch: The Unbroken Fin Tab

The Symptom: You turn the wall switch on and off, but both the top and bottom receptacles stay powered constantly. Alternatively, if you wired the switch loop incorrectly, flipping the switch trips the 15A breaker immediately.

The anatomy of a standard duplex receptacle features two isolated circuits joined by metal fin tabs. The silver side (neutral) is almost always left intact because the neutral return path is shared. The brass side (hot) must be physically severed to create two independent hot feeds.

If you forget to break the brass tab, the always-hot black wire backfeeds the switched-hot red wire. The top receptacle receives constant power, entirely bypassing the wall switch. Furthermore, the red wire carries that 120V back to the switch box, energizing the switch's load terminal even when the switch is in the "off" position. Always visually inspect the receptacle with a flashlight before pushing it into the box to confirm the brass gap is clear.

Verify and Test: Expected Meter Readings

Do not just plug in a lamp and hope for the best. Use your digital multimeter to verify the circuit topology before applying a load. Turn the 15A breaker back on at the panel. Set your multimeter to AC Voltage (V~) and place the black lead on the bare ground wire (or the center ground screw) and the red lead on the brass terminal screws.

Test Point Switch Position Expected Multimeter Reading What it Proves
Bottom Brass Screw (Black Wire) OFF 120V (± 5V) Always-hot feed from panel is intact.
Top Brass Screw (Red Wire) OFF 0.0V Switch is successfully breaking the load.
Top Brass Screw (Red Wire) ON 120V (± 5V) Switched-hot feed is completing the circuit.
Silver Screw (White Wire) N/A 0.0V (to Ground) Neutral is bonded at panel, not floating or cross-wired to hot.
Pro-Tip for 20A Circuits: If your breaker is 20A, you must upgrade all materials in this guide to 12 AWG. Use 12/2 and 12/3 NM-B cable, and install a 20A receptacle (identified by the T-shaped neutral slot). The physical steps, terminal colors, and tab-breaking procedure remain exactly the same, but you must use a heavier wire stripper gauge and apply slightly more torque to the terminal screws.

By following this exact topology, you ensure a safe, code-compliant split receptacle that provides both switched ambiance lighting and constant utility power from a single standard gang box.