How to Wire a 3-Prong Toggle Switch

Complete wiring guide for toggle switches

3-Prong Toggle Switch Wiring Diagram

Understanding the 3 Prongs

Prong 1: Common Terminal (COM)
Prong 2: Normally Open (NO)
Prong 3: Normally Closed (NC)

⚠️ Safety First

  • • Turn off power at the circuit breaker
  • • Use a voltage tester to confirm power is off
  • • Wear safety glasses and insulated gloves
  • • Follow local electrical codes

Step-by-Step Wiring Instructions

1

Identify the Terminals

Locate the three terminals on your toggle switch. They are usually marked as COM (Common), NO (Normally Open), and NC (Normally Closed).

2

Connect the Power Source

Connect the hot wire (usually black) from your power source to the Common (COM) terminal. This is the input terminal that receives power.

3

Connect the Load

Connect the wire going to your device/load to either the NO or NC terminal, depending on your desired switch behavior:
NO: Device turns ON when switch is flipped
NC: Device turns OFF when switch is flipped

4

Secure Connections

Tighten all terminal screws securely. Ensure no bare wire is exposed outside the terminals to prevent short circuits.

5

Test the Connection

After mounting the switch, restore power and test the switch operation. Verify that the device responds correctly to switch positions.

Common Applications

  • • Lighting control systems
  • • Motor control circuits
  • • Equipment power switching
  • • Emergency stop functions
  • • Industrial machinery controls

Troubleshooting Tips

  • • Check for loose connections
  • • Verify correct terminal identification
  • • Test continuity with multimeter
  • • Ensure proper voltage rating
  • • Check for damaged switch contacts

Need Professional Toggle Switches?

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