Duplex receptacle wiring diagram
Light: on
Unplug the load and the lamp goes out — but the receptacle terminals stay live. That is why you meter an outlet before you trust it. The copper highlight is the live path, not a wire colour.
A duplex receptacle is two outlets in one body, fed by a hot on the brass side and a neutral on the silver side, with a tab joining each pair so both halves are powered together. A plugged-in load draws current across the two; unplug it and the terminals stay live.
How this circuit works
The hot lands on a brass screw and, through the intact brass tab, powers both brass terminals. The neutral does the same on the silver side. Any load plugged into either half now sits across a hot and a neutral, so current flows through it and it works. The receptacle does not care whether the load is there — its terminals are energized either way.
That last point is the safety habit worth forming early: an outlet with nothing in it is not a dead outlet. Toggle the load off in the diagram and the copper stays right on the terminals. Break the brass tab and the two halves come apart — which is the next diagram along.
Questions people ask
Why does a receptacle have two brass and two silver screws?
Because a duplex is two outlets in one body. The brass screws are the hot side, the silver screws the neutral side, and a factory tab links each pair so both outlets are fed from one set of conductors. Feed one screw and the tab carries power to its twin.
What are the tabs for?
They join the two halves so a single hot and a single neutral power both outlets. Leave them intact for an ordinary always-on duplex. Snap the brass tab and you can feed each half separately — that is a split receptacle.
Is the outlet live even with nothing plugged in?
Yes. The terminals are energized whenever the circuit is on, whether or not anything is plugged in — unplug the load in the diagram and the receptacle stays copper. A plug simply completes a path through whatever you connect. Always meter before you trust an outlet dead.
Related
- Split receptacle wiring — the same outlet with the brass tab broken.
- GFCI wiring diagram — protecting a string of these downstream.
- All wiring diagrams
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