A standard switched outlet diagram—commonly known as a half-hot or split-wired receptacle—allows you to control the top half of a duplex outlet with a wall switch while keeping the bottom half continuously powered. To achieve this, you must use a 12/3 NM-B cable between the switch and the outlet, break the brass connecting tab on the hot side of the receptacle, and land the always-hot black wire on the bottom brass screw, the switched red wire on the top brass screw, and the white neutral on the silver screw. This setup assumes a standard US 120V nominal residential circuit, copper conductors, and compliance with modern NEC switch-loop requirements.
Tools, Materials, and Device Ratings
Before pulling any wire, ensure your materials match the circuit breaker rating. For a modern 20-amp branch circuit, you must use 12 AWG copper wire and 20-amp rated devices. Do not mix 15-amp receptacles on a 20-amp breaker unless the receptacle is specifically rated for 20A pass-through (which standard residential duplexes are not).
| Item | Specification / Model | Purpose |
|---|---|---|
| Receptacle | Leviton 5366-SW (20A Spec Grade) | Heavy-duty split-wired outlet with side-clamp terminals |
| Toggle Switch | Leviton 1221-2SW (15A/20A) | Single-pole switch for the switched leg |
| Feed Cable | 12/2 NM-B (Romex) | Main power feed from the panel to the switch box |
| Switch Leg Cable | 12/3 NM-B (Romex) | Carries always-hot, switched-hot, and neutral to the outlet |
| Wire Connectors | Wago 221-412 Lever Nuts | Secure, reusable splices for 12 AWG solid copper |
| Wire Strippers | Klein Tools 11055 | Precision stripping without nicking 12 AWG copper |
| Multimeter | Fluke 117 (CAT III 600V) | Verifying dead circuits and testing final voltage |
Mains Safety and Preparation
Working inside an electrical box exposes you to 120V AC, which can cause fatal shock or arc flash. You must de-energize the circuit at the main service panel before opening any junction box. Turn off the specific branch circuit breaker, apply a physical lockout/tagout device or heavy tape over the breaker to prevent accidental re-energizing, and verify the circuit is dead using a known-working CAT III multimeter or non-contact voltage tester. Always test your tester on a known live source first. Local code may require a licensed electrician for new circuit runs; this guide reflects NEC-style guidance, but your local AHJ has final authority.
Proper lockout/tagout procedures, as outlined by OSHA standards, are not just for industrial jobsites—they are critical for residential DIYers working on live panels. Once the breaker is off and verified dead, strip 3/4 inch of insulation from all 12 AWG conductors using your Klein strippers, and fold the bare copper ground wires neatly into the back of the boxes.
Step-by-Step Switched Outlet Wiring Procedure
This procedure assumes power enters at the switch box via 12/2 NM-B, and a 12/3 NM-B cable runs from the switch box to the outlet box. This topology satisfies NEC 404.2(C), which requires a neutral conductor to be present at the switch location for future smart-switch compatibility.
Phase 1: Wiring the Switch Box
- Land the Line Hot: Connect the black wire from the incoming 12/2 power feed to the bottom brass terminal screw on the single-pole switch. Tighten to the manufacturer's torque specification (usually 12-14 in-lbs).
- Land the Switched Hot: Connect the red wire from the outgoing 12/3 NM-B cable to the top brass terminal screw on the switch. This red wire will carry the switched voltage to the outlet.
- Splice the Always-Hot Feed: Connect the black wire from the 12/3 NM-B cable directly to the black wire from the incoming 12/2 power feed using a Wago 221 lever nut. This provides continuous power to the bottom half of the outlet.
- Splice the Neutrals: Connect the white wire from the 12/2 feed and the white wire from the 12/3 cable together in a Wago lever nut. The switch itself does not terminate a neutral in a standard single-pole setup, but the neutral must pass through to the outlet box.
- Splice the Grounds: Connect all bare copper ground wires together with a green wire nut or Wago, and run a 12 AWG bare copper pigtail to the green ground screw on the switch yoke.
Phase 2: Prepping and Wiring the Outlet Box
- Break the Brass Tab: Locate the small brass fin connecting the two hot (brass) screws on the side of the Leviton receptacle. Using needle-nose pliers, grip the tab and snap it off. Do not break the silver tab on the neutral side. This isolates the top and bottom halves of the receptacle.
- Land the Always-Hot: Connect the black wire from the incoming 12/3 NM-B cable to the bottom brass screw on the receptacle. This ensures the bottom half is always live.
- Land the Switched Hot: Connect the red wire from the 12/3 NM-B cable to the top brass screw on the receptacle. This half will now respond to the wall switch.
- Land the Neutral: Create a 6-inch 12 AWG white copper pigtail. Connect one end to the silver terminal screw on the receptacle, and connect the other end to the white neutral wire from the 12/3 NM-B cable using a Wago lever nut.
- Land the Ground: Connect the bare copper ground wire from the 12/3 NM-B cable to the green grounding screw on the receptacle yoke. Ensure no stray copper strands are bridging the gap between the green screw and the brass/silver terminals.
Verification and Testing
Do not push the devices into the box and screw on the faceplate until you have verified the circuit logic. Pushing a miswired device into a crowded box can cause a ground-to-hot short that will violently trip the breaker and potentially damage the yoke.
- Restore power at the main breaker panel.
- Set your Fluke 117 multimeter to AC Volts (V~).
- Place the black probe on the bare copper ground wire and the red probe on the bottom brass screw (always-hot). You should read between 114V and 126V (120V nominal).
- Move the red probe to the top brass screw (switched-hot) with the wall switch in the OFF position. You should read 0V (or a negligible phantom voltage under 2V).
- Toggle the wall switch to the ON position. The multimeter should now read 114V to 126V on the top brass screw.
- Finally, plug a lamp into the top receptacle and a phone charger into the bottom receptacle to verify physical load operation before securing the faceplate.
The Most Common Botch (And How to Fix It)
The most frequent failure in a switched outlet diagram is forgetting to break the brass tab, or worse, breaking the silver neutral tab by mistake.
Symptom of forgetting the brass tab: The outlet will either remain constantly hot on both halves (if the switch is bypassed or miswired), or the switch will control both halves simultaneously. If you wired the always-hot black to the bottom brass and the switched-hot red to the top brass but left the tab intact, you have effectively tied the always-hot feed directly to the switched-hot wire. When you flip the switch, you are creating a dead short between the line and the load, which will instantly trip the breaker with a loud pop and potentially weld the switch contacts.
Symptom of breaking the silver tab: If you break the neutral tab but only connect one white neutral wire to the silver side, the top half of the outlet will be completely dead, as it lacks a return path to the panel. If this outlet is also feeding downstream receptacles, breaking the silver tab will kill power to every outlet further down the daisy chain.
The Fix: Always use a continuity tester or multimeter in resistance mode (ohms) on the bare device before installing it. Place probes on the top and bottom brass screws; it should read 'OL' (open loop/infinite resistance). Place probes on the top and bottom silver screws; it should read near 0.1 ohms (continuous). Additionally, avoid using the push-in 'backstab' terminals on the back of the receptacle. Under continuous loads near 15A, thermal expansion and contraction can cause backstabbed wires to loosen and arc. Always use the side-clamp screw terminals.
Switched Outlet Diagram FAQ
How do I wire a switched outlet with only 2-wire cable?
Prior to the 2011 NEC update, electricians used a 12/2 or 14/2 NM-B cable as a 'switch loop' where the white wire was re-identified with black tape and used as the always-hot feed down to the switch, and the black wire returned as the switched hot. However, modern NEC 404.2(C) requires a neutral conductor to be present at the switch box to accommodate smart switches and timers that require standby power. Therefore, running only 2-wire cable between the switch and the outlet is no longer code-compliant for new installations or full rewires. You must use 12/3 NM-B to carry the always-hot, the switched-hot, and the neutral. If you are repairing an existing legacy 2-wire switch loop, you must re-identify the white wire with black phase tape at both ends, but upgrading to 12/3 is highly recommended.
Can I make both halves of the outlet switched?
Yes. If your goal is to have the wall switch control a lamp plugged into the top receptacle and a vacuum or seasonal light plugged into the bottom receptacle, you simply omit the tab-breaking step. Leave the brass connecting tab completely intact. Run a single 12/2 NM-B cable from the switch to the outlet. Connect the switched-hot black wire to either brass screw (the intact tab will bridge the power to the other half), connect the white neutral to the silver screw, and the bare copper to the green screw. This is common in living rooms where a single switch controls multiple floor lamps.
Why does my breaker trip immediately when I turn on the switch?
If the breaker trips the moment you toggle the switch to ON, you have created a dead short. The most common cause in a switched outlet diagram is misidentifying the wires in the switch box, specifically tying the switched-hot wire directly to a neutral wire, or landing the switched-hot on the neutral silver terminal at the receptacle. Another cause is a ground fault where a nicked wire insulation inside the box is allowing the switched hot to touch the bare copper ground or the metal junction box. Turn the breaker back off, open both boxes, and verify that no white neutral wires are touching any brass terminals, and that the red/black switched wires are strictly isolated to the brass switch terminals and the top brass receptacle terminal.
