If you are staring at an open junction box trying to figure out what to buy at the hardware store, here is the direct answer: the standard types of light switches names are Single-Pole, 3-Way, 4-Way, Double-Pole, Dimmer, and Smart. Your existing wire count dictates which one you need. For a standard two-location control circuit (like a hallway), you need a 3-Way switch. In this guide, we will decode the switch names, run a decision path to select your device, and provide a complete, color-coded installation procedure terminating on the industry-standard Leviton 5603-2W 15A 3-Way Switch.

Decoding the Types of Light Switches Names

Before you touch a wire stripper, you must correctly identify the switch type currently in the wall. Misidentifying a 3-Way as a Single-Pole is the number one reason DIYers end up with a light that only works from one end of a hallway. According to Leviton's switch classification standards, residential switches are categorized by their internal contact mechanisms and terminal counts.

Switch Name Terminals (Excl. Ground) Screw Colors Wires in Box Primary Use Case
Single-Pole 2 2 Brass 1 Line, 1 Load, 1 Ground One switch controls one light.
3-Way 3 1 Black (Common), 2 Brass (Travelers) 1 Line/Load, 2 Travelers, 1 Ground Two switches control one light.
4-Way 4 2 Brass, 2 Black/Dark 4 Travelers, 1 Ground Middle switch in a 3+ switch circuit.
Double-Pole 4 2 Brass, 2 Black/Dark 2 Lines, 2 Loads, 1 Ground Switching 240V appliances (well pumps, heaters).
Pro-Tip: Never rely on the physical toggle position (up/down) to identify a switch. A 3-Way switch toggles the circuit between two traveler paths; it does not have a hardwired "ON" or "OFF" printed on the toggle like a Single-Pole does.

The Decision Path: Which Switch Do You Actually Need?

Use this decision tree to select the exact device for your junction box. This path assumes a standard US residential 120V lighting circuit protected by a 15A or 20A breaker.

If your circuit has... Then you need... Concrete Pick (15A Circuit)
Only 1 switch controlling the light, and 2 insulated wires (plus ground) in the box. Single-Pole Switch Leviton 1451-2W
2 different wall switches controlling the same light, and 3 insulated wires (plus ground) in the box. 3-Way Switch Leviton 5603-2W
3 or more switches controlling the same light, and you are replacing the middle switch (4 insulated wires, no line/load). 4-Way Switch Leviton 5604-2W
A 240V load (like a baseboard heater) requiring both hot legs to be switched simultaneously. Double-Pole Switch Leviton 5602-2W

Default Recommendation: For the remainder of this installation guide, we are terminating on the Leviton 5603-2W 15A 3-Way Switch. This is the most common point of failure and confusion in residential wiring, and mastering it covers the foundational logic for all multi-location switching.

Tools, Materials, and Mains Safety Protocol

⚠️ DANGER: MAINS VOLTAGE HAZARD
Working on line-voltage (120V AC) circuits can cause fatal electrocution or arc-flash fires. You must de-energize the circuit at the main breaker panel, apply a lockout/tagout device if possible, and verify the circuit is dead using a tested Non-Contact Voltage (NCV) tester and a digital multimeter before touching any bare copper. NEC-style guidance requires switching the ungrounded (hot) conductor; your local Authority Having Jurisdiction (AHJ) has final authority on code compliance. If you are unsure, hire a licensed electrician.

Assumptions for this build: 120V nominal AC supply, 15A breaker, 14 AWG copper conductors (NM-B or THHN), standard plastic or metal single-gang junction boxes.

Tools & Materials List

  • Device: Leviton 5603-2W 15A 3-Way Switch (Qty 2 if replacing both ends)
  • Wire: 14 AWG solid copper (matching existing circuit; use 12 AWG if on a 20A breaker)
  • Tester 1: Klein Tools NCVT-1 Non-Contact Voltage Tester
  • Tester 2: Digital Multimeter (Fluke 115 or equivalent) for voltage and continuity verification
  • Hand Tools: Wire strippers (calibrated for 14 AWG), Lineman's pliers, Phillips #2 screwdriver, flathead slotted screwdriver
  • Consumables: Black electrical tape (for re-identifying traveler wires), wire nuts (yellow or red for 14 AWG)

Step-by-Step: Wiring the Leviton 5603-2W 3-Way Switch

A 3-Way circuit requires two switches. We will wire Box 1 (The Line Box) where power enters from the panel, and Box 2 (The Load Box) where the wire continues up to the light fixture. The critical rule of 3-Way wiring: Line and Load always land on the dark Common screw; Travelers always land on the Brass screws.

Box 1: The Line Box (Power Source)

  1. Identify the Line Wire: With the breaker OFF, separate the wires. Turn the breaker ON temporarily, use your NCV tester to find the hot wire, and mark it. Turn the breaker OFF and verify dead again. This is your Black Line wire.
  2. Terminate the Line: Strip 3/4" of insulation from the Black Line wire. Hook it clockwise around the Black (Common) screw on the Leviton 5603-2W. Tighten firmly (approx. 12 in-lbs) so the insulation sits flush against the screw head washer.
  3. Terminate Traveler 1: Strip the Red traveler wire from the 3-wire cable running to Box 2. Hook it clockwise around the top Brass screw. Tighten securely.
  4. Terminate Traveler 2: Strip the White traveler wire from the same 3-wire cable. Code requires re-identifying this white wire as a hot conductor. Wrap a band of black electrical tape around the insulation near the stripped end. Hook it clockwise around the bottom Brass screw. Tighten securely.
  5. Terminate Ground: Strip the Bare copper (or Green) ground wire. Hook it clockwise around the Green Ground screw at the bottom of the switch yoke. If using a metal junction box, pigtail the box ground to this wire as well.

Box 2: The Load Box (Fixture Side)

  1. Identify the Load Wire: This is the wire heading up to the ceiling fixture. It is typically the Black wire of a 2-wire cable going to the light. (Verify it is not hot with the NCV tester while the breaker is off).
  2. Terminate the Load: Strip the Black Load wire. Hook it clockwise around the Black (Common) screw on the second Leviton 5603-2W switch. Tighten firmly.
  3. Terminate Traveler 1: Strip the Red traveler wire coming from Box 1. Hook it to the top Brass screw. Tighten securely.
  4. Terminate Traveler 2: Strip the White traveler (with black tape) coming from Box 1. Hook it to the bottom Brass screw. Tighten securely.
  5. Terminate Ground: Hook the Bare copper ground wire to the Green Ground screw. Tighten securely.
Bench Note: Always use the screw terminals rather than the push-in "backstab" holes on the rear of the switch. Backstab connections rely on a small spring clip that loosens over time due to thermal expansion/contraction, leading to arcing and melted plastic housings—a frequent cause of residential electrical fires.

Verification, Testing, and the Most Common Botch

Do not push the switches back into the wall and apply faceplates until you have completed these verification steps. According to Mike Holt's NEC code interpretations, verifying proper grounding and circuit integrity is mandatory before energizing a newly terminated device.

Expected Meter Readings

  1. Ground Continuity Test (Breaker OFF): Set your multimeter to Continuity/Ohms (Ω). Place one probe on the switch's green ground screw and the other on a known good ground (like the bare copper in the box). Expected reading: < 1.0 Ω. If it reads OL (Open Loop), your ground path is broken.
  2. Voltage Verification (Breaker ON): Set your multimeter to AC Voltage. Carefully place the black probe on the Black (Common) screw of Box 1, and the red probe on the bare ground wire. Expected reading: 114V to 126V AC. If you read 0V, your breaker is off or the line wire is misidentified.
  3. Functional Toggle Test: With the breaker ON, toggle Switch 1. The light should change state. Walk to Switch 2 and toggle it. The light must change state regardless of the position of Switch 1.

The Most Common Botch and Its Symptom

The Botch: Landing the Black Line wire (or Black Load wire) on one of the Brass traveler screws instead of the Black Common screw. Because the brass screws look identical and are placed close together, DIYers frequently mix them up when shoving the wires into the back of the box.

The Symptom: The light will turn on and off perfectly from Switch A. However, when you walk to Switch B and toggle it, the light will either turn off and refuse to turn back on from either switch, or it will behave erratically. This happens because you have broken the logical SPDT (Single-Pole Double-Throw) routing; the current is being sent down a traveler path that has no return to the load.

The Fix: De-energize the panel. Pull the switch out. Move the single Line/Load wire to the isolated Black screw (the Common terminal), and ensure the two wires from the 3-wire traveler cable are on the Brass screws. The brass screws are electrically interchangeable with each other, but the black screw stands alone. Get that right, and your 3-way circuit will function flawlessly for decades.