A half hot outlet (technically called a switched or split-wired receptacle) provides an always-on 120V source on one half of the duplex, while the other half is controlled by a wall switch. This configuration is standard in living rooms and bedrooms where a hardwired overhead light is absent, allowing a floor lamp to be switched from the door while a vacuum or router remains on an unswitched circuit. To execute this, you must run a 3-wire cable (14/3 or 12/3 NM-B) from the switch to the receptacle and physically break the connecting brass fin on the hot side of the outlet.

Below is the complete half hot outlet wiring diagram walkthrough, tracing the circuit from the breaker panel to the load, mapping every terminal, and detailing how to verify the work with a digital multimeter.

Terminal Mapping and Diagram Symbols

Before pulling wire, you must understand how the physical device maps to the schematic. In standard NEC-compliant wiring diagrams, a half-hot receptacle is depicted as a standard duplex symbol (a circle with two parallel vertical slots and a D-shaped ground) but with the top half shaded or marked with a 'switched' indicator line. The single-pole switch is shown as a standard SPST symbol (a line breaking a circle) in series with the top hot terminal.

The physical 15A or 20A tamper-resistant (TR) duplex receptacle has four main terminal screws and one ground screw. The critical step in a split-wired setup is isolating the top and bottom hot terminals by snapping off the brass break-off tab. The silver (neutral) tab must remain intact.

Physical Terminal Screw Color Wire Color (NM-B) Diagram Symbol Circuit Function in Half-Hot
Top Hot Brass Red (Switched Leg) Shaded top half of receptacle symbol Switched 120V load (e.g., lamp)
Bottom Hot Brass Black (Always Hot) Unshaded bottom half of receptacle symbol Continuous 120V unswitched load
Neutral (Both) Silver White (Neutral) Return line to panel bus bar Shared 120V return path (tab intact)
Ground Green Bare / Green Earth / Equipotential bond symbol Fault current path to ground bus
Switch Line In Brass / Black Black (Panel Feed) SPST switch input node Unswitched 120V feed from breaker
Bench Tip: When breaking the brass fin on the side of the receptacle, use lineman's pliers to grip the small tab and twist it back and forth until it snaps. Do not use a screwdriver to pry it off, as you can easily crack the internal bakelite or thermoplastic housing, which compromises the terminal tension and creates a fire hazard.

Node-by-Node Wiring Trace: Source to Load

This trace assumes a standard 15A branch circuit using 14/2 NM-B from the panel to the switch box, and 14/3 NM-B from the switch box to the receptacle box. If you are on a 20A circuit (kitchen, dining, or specific living area requirements per NEC 210.11), upgrade all wire to 12 AWG (12/2 and 12/3 NM-B) and use a 20A receptacle.

Node 1: Panel to Switch Box (The Feed)

  1. Breaker to Switch: A 14/2 NM-B cable leaves the panel. The black (hot) wire lands on the 15A single-pole breaker. The white (neutral) lands on the neutral bus bar. The bare ground lands on the ground bus bar.
  2. Switch Box Entry: The 14/2 enters the switch box. The bare ground is pigtailed to the switch's green ground screw and bonded to the metal box (if applicable) per NEC 250.148.
  3. Switch Termination: The black wire from the panel connects to one of the brass terminals on the single-pole switch. (Standard single-pole switches do not have line/load polarity requirements, but consistency is good practice).

Node 2: Switch Box to Receptacle Box (The 3-Wire Run)

  1. The 14/3 NM-B Cable: This cable contains Black, Red, White, and Bare wires. It acts as the bridge carrying both the always-hot and the switched-hot to the outlet.
  2. Switch Box Splices:
    • The Red wire of the 14/3 connects to the other brass terminal on the switch. This is your switched leg.
    • The White wire of the 14/3 is spliced (using a wire nut or Wago connector) to the White wire of the incoming 14/2 panel feed. This passes the neutral through to the receptacle.
    • The Bare wire of the 14/3 is spliced to the incoming bare ground and the switch ground pigtail.
    • The Black wire of the 14/3 is spliced to the Black wire of the incoming 14/2 panel feed. This passes the always-hot through to the receptacle.
Code Caveat: In this specific topology, the white wire in the 14/3 cable is used strictly as a neutral pass-through, not as a re-identified hot wire. Therefore, you do not need to wrap it in black electrical tape. However, if you were wiring a switch loop (power to the receptacle first, then up to the switch), the white wire in a 2-wire cable would be the always-hot feed down to the switch and must be re-identified with black tape at both ends per NEC 200.7(C)(1).

Node 3: Receptacle Terminations

  1. Break the Tab: Snap off the brass fin connecting the top and bottom brass screws. Leave the silver fin intact.
  2. Switched Hot: Connect the Red wire from the 14/3 to the Top Brass screw.
  3. Always Hot: Connect the Black wire from the 14/3 to the Bottom Brass screw.
  4. Neutral: Connect the White wire to either Silver screw (the intact fin bridges the connection to both halves of the outlet).
  5. Ground: Connect the Bare wire to the Green screw.

Polarity, Grounding, and the Neutral Path

Understanding the neutral and ground paths is where most DIY errors occur in split-wired circuits. Because both halves of the receptacle share the same neutral return, the silver terminals must remain bonded. If you accidentally break the silver tab, the bottom half of the outlet will have no return path, and devices plugged into it will not function, even though a non-contact voltage tester will show 'hot' on the brass side.

The grounding path (equipotential bonding) must be continuous from the panel ground bus, through the switch box, and terminating at the receptacle's green screw and metal yoke. According to the NFPA National Electrical Code (Article 406.4), all 15A and 20A receptacles installed in dwelling units must be tamper-resistant (TR) and listed. Ensure the bare ground wire is looped clockwise under the green screw so that tightening the screw pulls the loop closed rather than pushing it out.

If you are daisy-chaining additional standard (always-hot) receptacles downstream from this half-hot outlet, you must use pigtails for the black, white, and ground wires at the half-hot box. Do not use the receptacle's internal terminals to pass the feed-through current, as doing so interrupts the downstream circuit if the half-hot receptacle is removed for service.

Multimeter Verification and Testing

Never energize a newly wired split circuit without verifying the terminations. Grab a Category III or IV digital multimeter (like a Fluke 117 or Klein MM400) and perform these checks.

Step 1: De-Energized Continuity Checks (Breaker OFF)

Set your multimeter to Continuity (the diode/sound wave symbol). Verify the meter works by touching the probes together (should read < 1 ohm and beep).

  • Ground Path: Place one probe on the receptacle's green ground screw and the other on the panel's ground bus bar. Reading: < 1 ohm. If it reads OL (Open Loop), your ground is broken.
  • Neutral Path: Place one probe on the receptacle's silver screw and the other on the panel's neutral bus. Reading: < 1 ohm.
  • Short Check: Place probes between the black (always hot) and white (neutral) wires at the switch box before capping them. Reading: OL. If it reads near 0 ohms, you have a dead short and will trip the breaker immediately.

Step 2: Energized Voltage Checks (Breaker ON)

Turn the breaker ON. Set your multimeter to AC Voltage (V~). Keep the wall switch in the OFF position.

  • Bottom Receptacle (Always Hot): Insert probes into the bottom slots (Hot to Neutral). Expected reading: 114V to 126V. If you read 0V, the black wire is disconnected or the breaker is off.
  • Top Receptacle (Switched, Switch OFF): Insert probes into the top slots. Expected reading: 0V. If you read 120V here, your switch is wired incorrectly, bypassed, or you failed to break the brass tab and are backfeeding from the bottom half.
  • Top Receptacle (Switched, Switch ON): Flip the wall switch ON. Expected reading: 114V to 126V.
  • Ground Verification: Measure from the bottom Hot slot to the Ground hole. You should read line voltage (~120V). Measure from Neutral to Ground. You should read < 2V (ideally < 0.5V). A high neutral-to-ground voltage indicates a loose neutral connection somewhere in the trace.

For further reading on receptacle installation standards and split-wired circuit requirements, refer to the latest guidelines published in Electrical Contractor Magazine and your local Authority Having Jurisdiction (AHJ). Always remember that while NEC-style guidance provides the baseline for safe installation, your local inspector has the final authority on code compliance in your specific municipality.