How to Wire a Plug | Black to Brass, White to Silver

A plug with reversed polarity will power a device just fine — but the safety ground may be compromised, and the internal switch might break the neutral instead of the hot wire, leaving the chassis live. How to wire a plug correctly takes about ten minutes and follows a simple color code that stays the same across every standard US 3-prong plug.

The Standard Color Code for 3-Prong Plugs

Every NEMA 5-15 plug (the common 3-prong type rated for 15 amps and 125 volts) uses the same terminal arrangement. The table below shows which wire connects where.

The ground pin is deliberately longer than the two flat blades so the device is grounded before power reaches it. On a correctly wired receptacle, ground is at the bottom, hot on the right, and neutral on the left. If the plug has one blade wider than the other, that wide blade is neutral — a feature called polarization that ensures correct orientation.

Wiring a Standard 3-Prong Plug in 5 Steps

These steps apply to any rewirable NEMA 5-15 or CSA 22.2 Nº42 plug. Work with the device unplugged and the breaker off.

1. Prepare the cord. Strip about 2 inches of the outer jacket with a wire stripper or utility knife, being careful not to nick the insulation on the inner conductors. Strip roughly 1/2 inch (12 mm) of insulation from the end of each conductor — black, white, and green or bare.
2. Open the plug. Remove the screw or screws that hold the two halves of the plug body together. Inside you will find three terminals, each marked by screw color or a stamp.
3. Connect the wires. Loosen each terminal screw just enough to slide the wire under the head. Wrap the wire clockwise around the screw — this is critical, because tightening the screw then pulls the wire tighter rather than pushing it off. Black to brass (hot), white to silver (neutral), green or bare to green (ground).
4. Clamp the cable. Position the cord so the outer jacket sits under the strain-relief clamp, not the individual insulated wires. Tighten the clamp securely. This is the most commonly skipped step and the one that causes most pull-out failures.
5. Close and test. Reassemble the housing and tighten all screws. Before plugging in, verify your wiring with a multimeter or a receptacle tester — check for continuity between the correct terminals and confirm there is no short between hot and neutral or between hot and ground.

For anyone working with multiple connections or replacing damaged plugs, our roundup of tested wire connector plugs and terminals covers reliable options for different wire gauges and applications.

What Are the Most Common Wiring Mistakes?

The most frequent error is reversing hot and neutral — putting white on brass and black on silver. The device will still run, but the internal switch will break the neutral instead of the hot wire, leaving the device’s internal wiring energized even when switched off. Clamping the individual wires instead of the outer jacket is the second most common mistake; a single strong pull on the cord can yank the conductors loose from the terminals. Leaving bare copper exposed beyond the terminal screw creates a short risk if the exposed wire touches the metal housing or another terminal. Wrapping the wire counterclockwise around the screw means tightening pushes the wire off instead of pulling it in. And using an undersized plug — a plug rated below the appliance’s current draw — is a genuine fire hazard.